fibrin and Arthritis--Rheumatoid

Post-translational modifications of proteins occur very frequently. One of these modifications, citrullination, is the result of arginine deimination operated by an enzyme, peptidylarginine deiminase (PAD), whose activity is under strict genetic control. Serum antibodies reactive with citrullinated proteins/peptides are a very sensitive and specific marker for rheumatoid arthritis. Genes encoding for PAD enzymes have been investigated in RA: the PADI4 gene confers susceptibility to RA in Japanese patients, but not in Caucasians.

Topics: Animals; Arthritis, Rheumatoid; Autoimmune Diseases; Citrulline; Fibrin; Humans; Hydrolases; Protein-Arginine Deiminases

Intracavitary fibrin clots may initiate pannus formation and the immunopathology of RA. Two critical steps, probably host dependent, may determine the development of RA: an altered regulation of extravascular haemostasis or an aberrant reactivity of synovial fibroblasts to the adhered fibrin clots. Current treatments for RA target events downstream of fibrin deposition, perhaps agents acting at an earlier stage should be tried.

Topics: Arthritis, Rheumatoid; Blood Coagulation Disorders; Fibrin; Fibrinolysis; Humans; Synovitis

Topics: Animals; Arthritis, Rheumatoid; Fibrin; Fibrinolysin; Fibrinolysis; Humans; Joints; Plasminogen Activators

Topics: Arthritis, Rheumatoid; Autoantibodies; Fibrin; Filaggrin Proteins; Humans; Imines; Intermediate Filament Proteins; Prognosis

The patterns of degradation and the influence of factor XIII polymerization on fibrin stability were examined in vitro following incubation with leukocyte elastase. In vivo experiments, various factor XIII-polymerized fibrin clots were implanted subcutaneously in mice to evaluate the stability of clots in the extravascular space. Both in vitro and in vivo lysis proceeded faster with nonpolymerized fibrin and was not influenced by the presence of cross-linked alpha 2-plasmin inhibitor. In vivo lysis of implanted clots was prevented by elastatinal, powerful elastase inhibitor, suggesting that granulocyte elastase is chiefly responsible for clot lysis in the extravascular space. To further extend investigations on the mechanisms of fibrinolysis in tissues, we evaluated fibrin and its degradation products in the synovial space. Expression of factor XIII in synovial cells and activities of coagulation factors, fibrinolytic enzymes, and inhibitors were investigated in the synovial fluid of rheumatoid arthritis patients. Immunohistochemical analysis showed deposits of insoluble fibrin on synovial membranes and pannus to an extent related to the progression of the disease. Factor XIII was expressed by fibroblasts and macrophages in the early stages of the disease, whereas in advanced stages factor XIII staining was associated with fibrin. The reduction of certain coagulation factors and high level of thrombin-antithrombin complexes in synovial fluid show a steady activation of the coagulation cascade. The evaluation of fibrinogen degradation products and the pattern of degradation of synovial fibrin(ogen) suggest the participation of leukocyte elastase in fibrin(ogen) lysis in synovial tissue of rheumatoid arthritis.

Topics: Arthritis, Rheumatoid; Fibrin; Fibrinolysis; Humans; Models, Cardiovascular; Synovial Fluid

Topics: Arthritis, Rheumatoid; Connective Tissue; Fibrin; Humans; Necrosis; Rheumatoid Factor; Rheumatoid Nodule; Synovitis; Wounds and Injuries

Topics: Arthritis, Rheumatoid; Binding Sites; Cell Transformation, Neoplastic; Collagen; Disseminated Intravascular Coagulation; Fibrin; Fibronectins; Humans; Molecular Weight; Opsonin Proteins; Sepsis; Surgical Procedures, Operative; Wounds and Injuries

Topics: Animals; Antigens; Arthritis, Rheumatoid; Autoimmune Diseases; Cartilage; Cattle; Cell Membrane Permeability; Densitometry; Esterases; Fibrin; Fibrinolysis; Histocytochemistry; Humans; Hyaluronoglucosaminidase; Hydrocortisone; Inflammation; Kinins; Leukocytes; Lysosomes; Mice; Microscopy, Electron; Neuraminidase; Oxidation-Reduction; Peptide Hydrolases; Phagocytosis; Phosphoric Monoester Hydrolases; Pinocytosis; Proteins; Rabbits; Rats; Rheumatic Diseases; Synovial Membrane; Synovitis

Topics: Animals; Arthritis, Rheumatoid; Autoradiography; Bence Jones Protein; Blood Chemical Analysis; Blood Coagulation; Chemical Precipitation; Chromatography, Gel; Fibrin; Fibrinogen; Half-Life; Humans; Immunoglobulin G; Iodine Isotopes; Methods; Polymers; Rabbits; Solubility

Topics: Antibodies, Antinuclear; Arthritis, Rheumatoid; Autoantibodies; Autoimmune Diseases; Collagen Diseases; Fibrin; Humans; Kidney; Leukocyte Count; Lupus Erythematosus, Systemic; Myocardium; Rheumatic Fever; Rheumatoid Factor; Skin; Synovial Membrane

Selected coagulation and fibrinolytic factors were evaluated in plasma and synovial fluid (SF) of 10 rheumatoid arthritis (RA) patients. Increased levels of fibrinogen were observed in plasma (p < 0.01), but only a trace amount of structurally intact fibrinogen was detected in the SF of RA patients, while immunostaining showed deposits of insoluble fibrin in their synovial membranes. Reduced levels of protein C, antithrombin III and coagulation factors II, V, VII, VIII, IX, XII and XIII (p < 0.01), and high levels of thrombin-antithrombin III (TAT) complexes (p < 0.01), were found in SF as compared to their corresponding plasma levels. The increased levels of fibrinogen, TAT complexes, B beta 15-42 peptide and plasminogen activator inhibitor-1 (PAI-1) in plasma (p < 0.01) are consistent with an enhanced fibrin turnover and endothelial perturbation due to a systemic inflammatory state. Plasminogen and alpha 2-plasmin inhibitor activity in SF were significantly reduced as compared to the plasma levels (p < 0.01), whereas an increase in PAI-1 activity was found in SF as compared to plasma (p < 0.01). The detection of D-dimer and B beta 15-42 peptide (p < 0.01) in SF suggests an involvement of plasmin in the degradation of fibrin generated in synovial tissue. The high levels of elastase-alpha 1-proteinase inhibitor complexes and of thrombin-increasable fibrinopeptide A, as well as the pattern of fibrinogen degradation as identified in SF by double-dimension immunoelectrophoresis, suggest that elastase released from exudated granulocytes may play an important role in fibrino(geno)lysis and tissue damage in RA joints.

Topics: Adult; Antithrombin III; Arthritis, Rheumatoid; Blood Coagulation Factors; Female; Fibrin; Fibrinolysin; Fibrinolysis; Humans; Immunoelectrophoresis; Immunohistochemistry; Male; Pancreatic Elastase; Plasminogen; Plasminogen Activator Inhibitor 1; Protein C; Synovial Fluid; Synovial Membrane

Topics: Adult; Aged; Arteriosclerosis; Arthritis, Rheumatoid; Blood Coagulation; Clinical Trials as Topic; Ethylestrenol; Female; Fibrin; Fibrinogen; Fibrinolysis; Humans; Male; Middle Aged; Phenformin; Placebos; Time Factors; Vascular Diseases

Hemophilic arthropathy (HA) is characterized by joint damage following recurrent joint bleeds frequently observed in patients affected by the clotting disorder hemophilia. Joint bleeds or hemarthroses trigger inflammation in the synovial tissue, which promotes damage to the articular cartilage. The plasminogen activation system is integral to fibrinolysis, and the urokinase plasminogen activator, or uPA in particular, is strongly upregulated following hemarthroses. uPA is a serine protease that catalyzes the production of plasmin, a broad-spectrum protease that can degrade fibrin as well as proteins of the joint extracellular matrix and cartilage. Both uPA and plasmin are able to proteolytically generate active forms of matrix metalloproteinases (MMPs). The MMPs are a family of >20 proteases that are secreted as inactive proenzymes and are activated extracellularly. MMPs are involved in the degradation of all types of collagen and proteoglycans that constitute the extracellular matrix, which provides structural support to articular cartilage. The MMPs have an established role in joint destruction following rheumatoid arthritis (RA). They degrade cartilage and bone, indirectly promoting angiogenesis. MMPs are also implicated in the pathology of osteoarthritis (OA), characterized by degradation of the cartilage matrix that precipitates joint damage and deformity. HA shares a number of overlapping pathological characteristics with RA and OA. Here we discuss how the plasminogen activation system and MMPs might exacerbate joint damage in HA, lending insight into novel possible therapeutic targets to reduce the comorbidity of hemophilia.

Topics: Arthritis, Rheumatoid; Collagen; Enzyme Precursors; Fibrin; Fibrinolysin; Hemarthrosis; Hemophilia A; Humans; Matrix Metalloproteinases; Osteoarthritis; Peptide Hydrolases; Plasminogen; Proteoglycans; Urokinase-Type Plasminogen Activator

Cartilage damage in inflammatory arthritis is attributed to inflammatory cytokines and pannus infiltration. Activation of the coagulation system is a well known feature of arthritis, especially in rheumatoid arthritis (RA). Here we describe mechanisms by which fibrin directly mediates cartilage degeneration.. Fibrin deposits were stained on cartilage and synovial tissue of RA and osteoarthritis (OA) patients and in murine adjuvant-induced arthritis (AIA) in wild-type or fibrinogen deficient mice. Fibrinogen expression and procoagulant activity in chondrocytes were evaluated using qRT-PCR analysis and turbidimetry. Chondro-synovial adhesion was studied in co-cultures of human RA cartilage and synoviocytes, and in the AIA model. Calcific deposits were stained in human RA and OA cartilage and in vitro in fibrinogen-stimulated chondrocytes.. Fibrin deposits on cartilage correlated with the severity of cartilage damage in human RA explants and in AIA in wild-type mice, whilst fibrinogen deficient mice were protected. Fibrin upregulated Adamts5 and Mmp13 in chondrocytes. Chondro-synovial adhesion only occurred in fibrin-rich cartilage areas and correlated with cartilage damage. In vitro, autologous human synoviocytes, cultured on RA cartilage explants, adhered exclusively to fibrin-rich areas. Fibrin co-localized with calcification in human RA cartilage and triggered chondrocyte mineralization by inducing pro-calcification genes (Anx5, Pit1, Pc1) and the IL-6 cytokine. Similar fibrin-mediated mechanisms were observed in OA models, but to a lesser extent and without pseudo-membranes formation.. In arthritis, fibrin plaques directly impair cartilage integrity via a triad of catabolism, adhesion, and calcification.. None.

Topics: Animals; Arthritis, Rheumatoid; Cartilage; Chondrocytes; Fibrin; Fibrinogen; Humans; Mice; Osteoarthritis; Synovial Membrane

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Neutrophils

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Neutrophils

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Neutrophils

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Neutrophils

Rheumatoid arthritis (RA) is associated with HLA-DRB1 genes encoding the shared epitope (SE), a 5-amino acid motive. RA is usually preceded by the emergence of anti-citrullinated protein/peptide antibodies (ACPAs). Citrulline is a neutral amino acid resulting from post-translational modification of arginine involved in peptidic bounds (arginyl residue) by PeptidylArginine Deiminases (PADs). ACPAs recognize epitopes from citrullinated human fibrin(ogen) (hFib) and can be specifically detected by the AhFibA assay. Five citrullinated peptides derived from hFib together represent almost all of the epitopes recognized by patients with ACPA-positive RA, namely: α36-50cit, α171-185cit, α501-515cit, α621-635cit, and β60-74cit. The use of antibody fine specificities as markers of clinical phenotypes has become a major challenge. Our objective was to study whether RA clinical characteristics and HLA-DRB1 genetic background were associated with a specific reactivity against the epitopes borne by the five peptides.. 184 ACPA-positive RA patients fulfilling the 2010 ACR/EULAR criteria were studied. Patient characteristics including HLA-DRB1 genotype, were collected from their medical files. Anti-CCP2 antibodies, AhFibA, and antibodies against the five citrullinated hFib (hFib-cit) peptides were analyzed by ELISA.. Anti-α505-515cit antibodies were associated with HLA-DRB1*04:01 (OR = 5.52 [2.00 - 13.64]; p = 0.0003). High level anti-α505-515cit antibodies were associated with rheumatoid nodules (OR = 2.71 [1.00 - 7.16], p= 0.044).. Immune complexes containing anti-α501-515cit antibodies and rheumatoid factors might be involved in the development of rheumatoid nodules on the HLA-DRB1*04:01 background. Apheresis of these epitope-specific antibodies might be a new therapeutic opportunity for patients with rheumatoid nodules.

Topics: Anti-Citrullinated Protein Antibodies; Arthritis, Rheumatoid; Epitopes; Female; Fibrin; HLA-DRB1 Chains; Humans; Male; Middle Aged; Peptides; Rheumatoid Factor

This study sought to identify different subpopulations of extracellular vesicles (EVs) in plasma from female patients with established rheumatoid arthritis (RA) in relation to the activation of coagulation and fibrin formation in these patients. Forty women were included in the study, 20 patients and 20 age-matched healthy controls. The mean disease duration in patients was 13.0 (5.0-25.0) years, with medium to high disease activity despite ongoing treatment with low-dose prednisolone and methotrexate. There were no differences between the investigated groups regarding the presence of traditional cardiovascular risk factors. The concentration of phosphatidylserine-positive (PS

Topics: Adult; Aged; Arthritis, Rheumatoid; Biomarkers; Blood Coagulation; Blood Coagulation Tests; Disease Management; Disease Susceptibility; Extracellular Vesicles; Female; Fibrin; Gene Expression; Humans; Male; Middle Aged; Thrombosis

Morning stiffness is a hallmark symptom of rheumatoid arthritis (RA), but its etiology is poorly understood. This study was undertaken to determine whether any histologic features of synovium are associated with this symptom.. Data on patient-reported morning stiffness duration and severity, and Disease Activity Score in 28 joints (DAS28) were collected from 176 patients with RA undergoing arthroplasty. Synovium was scored for 10 histopathologic features: synovial lining hyperplasia, lymphocytes, plasma cells, Russell bodies, binucleate plasma cells, fibrin, synovial giant cells, detritus, neutrophils, and mucin. Fibrinolysis of clots seeded with various cell types was measured in turbidimetric lysis assays.. Stiffness severity and morning stiffness duration were both significantly associated with DAS28 (P = 0.0001 and P = 0.001, respectively). None of the synovial features examined were associated with patient-reported stiffness severity. The presence of neutrophils and fibrin in RA synovial tissue were significantly associated (P < 0.0001) with patient-reported morning stiffness of ≥1 hour, such that 73% of patients with both synovial fibrin and neutrophils reported morning stiffness of ≥1 hour. Further, neutrophils and fibrin deposits colocalized along the synovial lining. In in vitro analyses, fibrin clots seeded with necrotic neutrophils were more resistant to fibrinolysis than those seeded with living neutrophils or no cells (P = 0.008). DNase I treatment of necrotic neutrophils abrogated the delay in fibrinolysis.. In RA, prolonged morning stiffness may be related to impaired fibrinolysis of neutrophil-enmeshed fibrin deposits along the synovial membrane. Our findings also suggest that morning stiffness severity and duration may reflect distinct pathophysiologic phenomena.

Topics: Arthritis, Rheumatoid; Female; Fibrin; Humans; Male; Middle Aged; Neutrophils; Severity of Illness Index; Synovial Membrane

Rheumatoid arthritis (RA) is an autoimmune disease associated with thrombotic complications. To elucidate pathogenic mechanisms, hemostatic disorders in RA were correlated with other laboratory and clinical manifestations. Hemostasis was assessed using relatively new complementary tests, the spatial growth of a plasma clot (Thrombodynamics assay), and contraction of whole blood clots. Platelet functionality was assessed with flow cytometry that quantified the expression of P-selectin and the fibrinogen-binding capacity of platelets before and after activation with a thrombin receptor-activating peptide. Parameters of fibrin clot growth and the kinetics of contraction of blood clots were significantly altered in patients with RA compared to the control group. In Thrombodynamics measurements, an increase in the clot growth rate, size, and optical density of plasma clots altogether indicated chronic hypercoagulability. The rate and extent of blood clot contraction in patients with RA was significantly reduced and associated with platelet dysfunction revealed by an impaired response to activation. Changes in the parameters of clot growth and contraction correlated with the laboratory signs of systemic inflammation, including hyperfibrinogenemia. These results confirm the pathogenic role of hemostatic disorders in RA and support the validity of fibrin clot growth and the blood clot contraction assay as indicators of a (pro)thrombotic state.

Topics: Adult; Aged; Arthritis, Rheumatoid; Blood Coagulation; Female; Fibrin; Fibrinogen; Humans; Male; Middle Aged; P-Selectin; Thrombosis; Young Adult

The risk of cardiovascular events in patients with Rheumatoid Arthritis (RA) is disproportionately heightened as a result of systemic inflammation. The relative effect of autoimmune-associated citrullination on the structure and thrombotic potential of fibrin(ogen) remains unknown. We therefore compared indices of vascular function, inflammation, coagulation and fibrin clot composition in RA patients with healthy controls and evaluated parameter association with disease presence.. Blood samples were collected from 30 RA patients and 30 age- and gender-matched healthy volunteers. Levels of serum amyloid A (SAA), c-reactive protein (CRP), soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular cell adhesion molecule 1 (sVCAM-1) was measured using a sandwich immunoassay. Whole blood coagulation was assessed using Thromboelastography (TEG. Concentrations of SAA, CRP and ICAM-1 were significantly elevated in RA patients compared to controls. TEG parameters relating to coagulation initiation, rate of fibrin cross-linking, and time to reach maximum thrombus generation were attenuated in RA patients. Microscopic analysis revealed denser networks of thicker fibrin fibers in RA patients compared to controls and multiple citrullinated regions within fibrin clot structures in RA patients were present.. Our findings provide novel evidence for the citrullination of fibrin within vasculature is more prominent in RA plasma compared to control plasma and plasma is more accessible than synovial fluid. Citrullinated fibrinogen could play a role as a determinant of thrombotic risk in RA patients.

Topics: Adult; Aged; Arthritis, Rheumatoid; Blood Coagulation; C-Reactive Protein; Citrullination; Female; Fibrin; Humans; Inflammation; Intercellular Adhesion Molecule-1; Male; Middle Aged; Serum Amyloid A Protein; Thrombosis; Up-Regulation; Young Adult

The objective of the study was to compare the diagnostic yield of home-made ELISA tests based on synthetic chimeric fibrin/filaggrin citrullinated peptides (CFFCPs) with CCP3 and CCP3.1 commercial tests to detect anti-citrullinated protein/peptide antibodies (ACPAs) in rheumatoid arthritis (RA) patients. The prognostic value is also studied in a cohort of patients with early RA. Moreover, we transfer immunological assays from microtiter plates to microarray formats to allow the simultaneous analysis of several peptide sequences and reduce the volume of serum from patients.. The diagnostic study includes: 100 RA patients who fulfilled the 1987 ACR criteria; 100 healthy blood donors; 35 patients with SLE according ACR criteria; 35 patients with PsA fulfilling the Wright and Moll criteria and 30 patients with HCV infection. The prognostic value study includes 50 patients with early RA with follow-up data available. All samples are from outpatients attending the Rheumatology Department of the Hospital Clinic of Barcelona.. Similar sensitivity, specificity and predictive values for the diagnosis of RA of CCFCPs compared to CCP3/CCP3.1 were obtained. Although a high concordance is observed between anti-CFFCPs and anti-CCP3/CCP3.1 in the early patients that rendered Larsen radiographic progression, CFFCPs could be a better marker of radiographic outcome. Strong correlations between the microarray and ELISA results were found for individual CFFCPs peptides.. The development of multiplexing techniques combining a different spectrum of markers in a single analysis, including CFFCP peptides, could allow a more detailed analysis of the autoantibodies reactivity found in the sera of patients suffering of this heterogeneous disease.

Topics: Anti-Citrullinated Protein Antibodies; Arthritis, Rheumatoid; Biomarkers; Citrulline; Enzyme-Linked Immunosorbent Assay; Fibrin; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Peptides, Cyclic; Prognosis; Protein Array Analysis; Protein Domains

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Thromboembolism; Thrombosis

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Thromboembolism; Thrombosis

Quantification of Abs toward a single epitope is critical to understanding immunobiological processes. In autoimmunity, the prognostic value of the serological profiles of patients draws much attention, but the detection of Abs toward a single epitope is not well controlled. Particularly, the rheumatoid arthritis (RA)-specific anti-citrullinated protein/peptide Abs (ACPA) are specific to a two-atom change on arginyl residues and are considered a heterogeneous family of Abs. As a model, we studied ACPA to decipher how peptide features used as immunosorbent impact Ab detection. We synthesized 30 peptides encompassing immunodominant epitopes of citrullinated fibrin differing by their length and biotin location and tested them using ELISA with 120 sera from RA and non-RA rheumatic disease controls, generating over 3000 experimental measurements. We showed that minor molecular changes in peptide chemical structure had dramatic consequences. Even when peptides exhibited the same epitope, measured Ab titers were extremely variable, and patients' seropositivity was discordant in up to 50% of cases. The distance between epitope and biotin was the most critical parameter for efficient Ab detection irrespective of biotin position or peptide length. Finally, we identified a 15-mer peptide bearing a single citrullinated epitope detecting almost all ACPA-positive sera, thus revealing a high degree of homogeneity in RA autoimmune response. This integrative analysis deciphers the dramatic impact of the molecular design of peptide-based technologies for epitope-specific Ab quantification. It provides a model for assay development and highlights that the studies using such technologies can give a wrong perception of biological processes and therefore that medical use of data must be cautious.

Topics: Anti-Citrullinated Protein Antibodies; Arthritis, Rheumatoid; Citrullination; Diagnostic Errors; Enzyme-Linked Immunosorbent Assay; Epitopes; Fibrin; Humans; Immunity, Humoral; Immunosorbents; Peptides; Serology

A variety of bioimaging tools assists in the diagnosis and evaluation of rheumatoid arthritis (RA) and other osteoarthritis. However, detection of RA in the early stages by targeting its macrophages with suitable contrast agents will help in arresting the progression of the disease.. In the present study, we investigated the effectiveness of using magnetic fibrin nanoparticles (MFNPs) conjugated with folic acid (FA-MFNPs) as a specific contrast agent to target the activated macrophages, which overexpress the folate receptors (FR) in the knee joints of rats with antigen-induced arthritis (AIA).. FA-MFNPs were spherical with an average size of 18.3±1.6nm. In vitro studies have shown effective internalization of FA-MFNPs into the Raw264.7 macrophage cells. In vivo studies were carried out by injecting FA-MFNPs intravenously into the arthritic rats. The results showed enhanced MR imaging in the synovium of arthritic joints. Prussian blue histological staining confirmed uptake of FA-MFNPs by macrophages in the synovial tissue.. The animal experiment results indicate that FA-MFNPs can be used as a specific MRI contrast agent in identifying phagocytic active macrophages in the synovial joints.. Blood is the precursor source for synthesising the fibrin-based iron oxide (magnetic) nanoparticles (MFNPs) with diameters between 12 and 15nm. It has excellent superparamagnetic behaviour, biocompatibility, osteogenic potency, hemocompatibility, and biodegradable properties. MFNPs-based nanocomposites might be a promising contrast agent for bioimaging.

Topics: Animals; Arthritis, Rheumatoid; Contrast Media; Endocytosis; Fibrin; Folic Acid; Goats; Hydrodynamics; Liver; Macrophages; Magnetic Resonance Imaging; Magnetite Nanoparticles; Male; Mice; Powders; Rats, Wistar; RAW 264.7 Cells; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Staining and Labeling; Static Electricity; X-Ray Diffraction

Although several infectious agents and particularly Epstein-Barr virus (EBV) have been suspected to be involved in aetiology of rheumatoid arthritis (RA), their role still remains elusive. Almost 80% of RA sera contain antibodies to citrullinated proteins/peptides. Among them, the autoantibodies to citrullinated human fibrinogen (AhFibA) are composed of two non-cross-reactive subsets directed to immunodominant epitopes borne by the α36-50Cit and β60-74Cit fibrin peptides. RA sera also contain antibodies towards the citrullinated EBNA35-58Cit peptide derived from the EBNA-1 protein of EBV. Here, using a large cohort of RA patients and controls, we showed that for a diagnostic specificity of 98.5%, 47% of the AhFibA-positive patients were anti-EBNA35-58Cit-positive and that almost all (98.5%) the anti-EBNA35-58Cit-positive were AhFibA-positive, whereas 86% were anti-β60-74Cit-positive and only 43% anti-α36-50Cit-positive. AhFibA, anti-EBNA35-58Cit- and anti-β60-74Cit-antibody titres were significantly correlated. Competition assays showed that anti-EBNA35-58Cit antibodies are highly cross-reactive with the β60-74Cit peptide. The demonstration that a citrullinated peptide derived from the EBNA-1 protein of EBV presents a molecular mimicry with human citrullinated fibrin constitutes an additional argument for a possible role of EBV in RA aetiopathogeny.

Topics: Antibodies; Arthritis, Rheumatoid; Case-Control Studies; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Epstein-Barr Virus Nuclear Antigens; Fibrin; Humans; Immunodominant Epitopes; Peptides

Originating from the synovium, multiple free-floating intra-articular particles, called rice bodies, typically resemble cartilage and have a fibrin structure. While the etiology of rice body formation is unclear, they often occur in rheumatoid arthritis and other seronegative arthropathies; they also occur in tuberculosis, though the incidence is much lower. They are often encountered by rheumatologists or clinical orthopedists. A 33-year-old female who suffered from occasional swelling and pain of her left knee for 3 months was admitted with a mechanically locked knee. Free-floating rice bodies were identified on magnetic resonance imaging (MRI), and arthroscopic intervention was performed for diagnostic and therapeutic purposes. After the removal of all bodies and effusion with mechanical irrigation, an arthroscopic subtotal synovectomy was performed.

Topics: Adult; Arthritis, Rheumatoid; Arthroscopy; Debridement; Female; Fibrin; Humans; Knee Joint; Magnetic Resonance Imaging; Synovectomy

To evaluate the proportions of rheumatoid arthritis (RA) sera containing anticitrullinated proteins autoantibodies (ACPA) reactive to α36-50Cit₃₈,₄₂ and/or β60-74Cit₆₀,₇₂,₇₄, two peptides identified as bearing the immunodominant epitopes of their major target, citrullinated fibrin. To analyse the relationships of anti-α36-50Cit₃₈,₄₂ and anti-β60-74Cit₆₀,₇₂,₇₄ autoantibodies with autoantibodies reactive to the complete citrullinated human fibrinogen molecule (AhFibA) and with anti-CCP2 antibodies.. 617 sera from 181 patients with established RA and 436 with non-RA rheumatic diseases were tested by ELISA for AhFibA, anti-CCP2, anti-α36-50Cit₃₈,₄₂, anti-β60-74Cit₆₀,₇₂,₇₄ autoantibodies, and by nephelometry for rheumatoid factor (RF). Diagnostic indexes, correlations and concordances between tests were analysed. Crossreactivity of anti-α36-50Cit₃₈,₄₂ and anti-β60-74Cit₆₀,₇₂,₇₄ autoantibodies was assessed in competition experiments.. At a diagnostic specificity of 95%, the diagnostic sensitivity of AhFibA (83%) was significantly higher than that of all other tests. The diagnostic sensitivity of anti-β60-74Cit₆₀,₇₂,₇₄ (71%) was significantly higher than that of anti-α36-50Cit₃₈,₄₂ autoantibodies (51%) but similar to that of anti-CCP2 (74%). Titres of RF, anti-α36-50Cit₃₈,₄₂ and anti-β60-74Cit₆₀,₇₂,₇₄ autoantibodies were weakly correlated with each other, whereas titres of anti-β60-74Cit₆₀,₇₂,₇₄ were strongly correlated with those of AhFibA (r=0.633) and anti-CCP2 (r=0.634). Anti-α36-50Cit₃₈,₄₂ and anti-β60-74Cit₆₀,₇₂,₇₄ mainly corresponded to two non-crossreactive subfamilies of ACPA. More than 90% of AhFibA-positive or anti-CCP2-positive sera recognised the α36-50Cit₃₈,₄₂ and/or the β60-74Cit₆₀,₇₂,₇₄ peptide.. Autoantibodies reactive to α36-50Cit₃₈,₄₂ and β60-74Cit₆₀,₇₂,₇₄ form two distinct, non-overlapping subfamilies of ACPA that, together, cover practically all the ACPA reactivity to citrullinated fibrinogen and to CCP2 antigens. In established RA, anti-β60-74Cit₆₀,₇₂,₇₄ autoantibodies show diagnostic indexes similar to those of anti-CCP2.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Arthritis, Rheumatoid; Autoantibodies; Case-Control Studies; Citrulline; Epitopes; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Humans; Male; Middle Aged; Peptide Fragments; Peptides, Cyclic; Rheumatic Diseases; Rheumatoid Factor; Young Adult

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes joint inflammation and extra-articular manifestations. To prevent progressive and irreversible structural damage, early diagnosis of RA is of paramount importance. Antibodies directed against citrullinated proteins and peptides (ACPAs) are the most specific serological markers available for diagnosing RA. ACPAs may be detected several years before symptoms appear, and their presence at disease onset is a good predictor of the development of erosive joint lesions. Synthetic peptides can replace cognate proteins in solid-phase assays for specific autoantibody recognition in RA patients. The use of synthetic peptides instead of proteins represents an advantage in terms of the reproducibility of such immunoassays. They give absolute control over the exact epitopes presented. Furthermore, it is difficult to prepare sufficient amounts of high-quality antigenic proteins with a well-defined degree of citrullination. Synthetic citrullinated peptides, in contrast, are easily obtained in a pure form with a well-defined chemical structure and the epitopes can be precisely oriented in the plate by covalent binding of the peptides. We have recently obtained and highlighted the application of chimeric peptides bearing different citrullinated protein domains for the design of RA diagnosis systems. Our results indicate that more than one serological test is required to classify RA patients based on the presence or absence of ACPAs. Each of the target molecules reported (fibrin, vimentin and filaggrin) helps to identify a particular subset of RA patients.

Topics: Amino Acid Sequence; Arthritis, Rheumatoid; Autoantibodies; Case-Control Studies; Citrulline; Early Diagnosis; Epitopes; Fibrin; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Joints; Molecular Sequence Data; Peptides; Prognosis; Protein Processing, Post-Translational; Protein Structure, Tertiary; Solid-Phase Synthesis Techniques; Vimentin

Fibrin deposits are characteristic of the synovial tissues in rheumatoid arthritis (RA). Once citrullinated, fibrin becomes an autoantigen and is thought to contribute in this way to perpetuate the disease. Our study aimed to analyse the responses of RA synovial fibroblasts (RASF) to native and citrullinated fibrin.. The transcriptome induced by fibrin in RASF was approached with whole-genome-based gene expression arrays. The upregulation of selected pro-inflammatory genes by fibrin was confirmed in additional primary cell cultures using quantitative PCR and ELISA. Citrullination reactions were carried out with recombinant human peptidylarginine deiminases (PAD) 2 and 4.. In the whole-genome array native fibrin was found to modulate the gene expression profile of RASF, particularly upregulating mRNA levels of several pro-inflammatory cytokines. The induction of interleukin (IL)-6 and IL-8 by fibrin was confirmed in additional samples at both the mRNA and the protein level. Blocking and knockdown experiments showed the participation of toll-like receptor (TLR)4 in the induction of both cytokines. As compared with the native macromolecule, PAD2-citrullinated fibrin induced significantly higher expression of the pro-inflammatory cytokines in these cells.. Our results suggest that fibrin mediates inflammatory responses in RASF via a TLR4 pathway. In this way, fibrin and particularly its citrullinated form may contribute to sustain the cytokine burst in RA.

Topics: Arthritis, Rheumatoid; Cell Survival; Cells, Cultured; Citrulline; Cytokines; Fibrin; Fibroblasts; Gene Expression; Gene Expression Profiling; Gene Expression Regulation; Gene Knockdown Techniques; Humans; Hydrolases; Oligonucleotide Array Sequence Analysis; Protein-Arginine Deiminase Type 2; Protein-Arginine Deiminase Type 4; Protein-Arginine Deiminases; Recombinant Proteins; RNA, Messenger; RNA, Small Interfering; Synovial Membrane; Toll-Like Receptors; Up-Regulation

Rheumatoid arthritis is a chronic inflammatory condition that affects mainly synovial joints and has an impact on approximately 1% of the Western population. The coagulation process is altered in this condition, and this is frequently complicated by thrombocytosis. Changes in fibrin morphology have been linked with inflammation, and this, in turn, plays an important role in thrombosis. Changes in the fibrin fiber formation cause the alterations observed in thrombus morphology. In the current study, the ultrastructure of platelets and fibrin networks was investigated to determine whether any morphological changes are present in these structures in patients suffering from rheumatoid arthritis. Six patients diagnosed with rheumatoid arthritis took part in this study, and their clot morphology was compared to that of control subjects. Citrated blood with and without the addition of thrombin was used. Results indicated that the fibrin networks in the arthritis patients formed thick, matted layers. This matted appearance is due to a changed ultrastructure of the minor, thin fibers. Also, in these patients, spontaneous networks were created without the addition of thrombin, which indicates an abnormal hemostatic protein functioning, and the latter is expressed as visible changes in ultrastructure.

Topics: Adult; Arthritis, Rheumatoid; Blood Coagulation; Blood Platelets; Case-Control Studies; Female; Fibrin; Humans; Male; Microscopy, Electron, Scanning; South Africa; Thrombin

Here we used solid-phase methods to prepare oligonucleotides carrying fibrin/ filaggrin citrullinated peptides. Post-synthetic conjugation protocols were successfully applied for the synthesis of oligonucleotides carrying small peptides. A stepwise protocol using acid treatment for the final deprotection allowed the preparation of polypyrimidine oligonucleotides carrying longer and arginine-rich peptides. An ELISA-based test using the oligonucleotide-citrullinated peptide conjugates was developed for the detection of anti-citrullinated protein/peptide antibodies in human serum from rheumatoid arthritis patients.

Topics: Antibodies; Arginine; Arthritis, Rheumatoid; Citrulline; Epitopes; Fibrin; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Oligonucleotides; Peptides; Solid-Phase Synthesis Techniques

Preliminary studies have shown the potential application for the diagnosis of Rheumatoid Arthritis (RA) patients with a severe disease course of an epitopic domain of β-fibrin. The aim of the present work was the analysis of the presence of antibodies against several β-fibrin synthetic peptides in relation to the immunogenetic background and disease course in a clinically well-defined RA patient cohort. Our results indicated that positive patients against anti-β-fibrin synthetic peptides have a higher percentage of HLA-DRB1 shared epitope (SE) than negative patients. We also observed that the presence of SE alleles was significantly associated with a higher level of anti-[Cit(376)]βfib(365-383) antibodies. When analyzing the effect of different SE alleles, we found a significant positive association between carriers of QRRAA allele and [Cit(376)]βfib(365-383) (Odds ratio 3.77; CI95%: 1.41-10.08). These results suggest that the anti-β-fibrin status is associated with the immunogenetic background of RA patients.

Topics: Alleles; Amino Acid Sequence; Antibodies; Arthritis, Rheumatoid; Cohort Studies; Epitopes; Fibrin; Follow-Up Studies; HLA-DR Antigens; HLA-DRB1 Chains; Humans; Molecular Sequence Data; Peptide Fragments

During blood clotting, thrombin and fibrinogen interact, whereby thrombin cleaves the fibrinogen molecule into two peptides, the fibrinopeptides, ultimately forming fibrin monomers. These fibrinogen monomers assemble to form a fibrin network that may be studied using ultrastructural techniques. This study investigates the use of a grid, placed onto a micrograph, to quantify changes in morphology. The fibrin fiber micrographs of a healthy donor were compared to a database of donors and were shown to be a true representative of a typical healthy individual. Eighteen micrographs of this single donor were taken at 40,000× machine magnification, and a grid was placed over the micrographs. The grid dimensions were calculated by using the scale bar inserted onto the micrograph. Each grid block was equal to 0.5 by 0.5 µm for a total grid area of 28 µm(2). A percentage changed fibrin fiber morphology was then calculated for each 28 µm(2) of fibrin clot produced in the laboratory. It is concluded that this effortless and simple grid technique to quantify changes in ultrastructure of fibrin clot morphology may provide a method to statistically quantify changes in fibrin fiber ultrastructure when studying conditions affecting hemostasis.

Topics: Adult; Arthritis, Rheumatoid; Blood Coagulation; Databases, Factual; Fibrin; Fibrinogen; Humans; Microscopy, Electron, Scanning; Protein Conformation; Reference Values; Tobacco Use Disorder

This work reports on the fabrication and performance of a simple amperometric immunosensor device to be potentially used for the detection of serum anti-citrullinated peptide antibodies (ACPAs), which are specific for rheumatoid arthritis (RA) autoimmune disease. Sera of RA patients contain antibodies to different citrullinated peptides and proteins such as fibrin or filaggrin. Herein, a chimeric fibrin-filaggrin synthetic peptide (CFFCP1) was used as a recognition element anchored to the surface of a multiwalled carbon nanotube-polystyrene (MWCNT-PS) based electrochemical transducer. The transducer fabrication process is described in detail together with its successful electrochemical performance in terms of repeatability and reproducibility of the corresponding amperometric response. The resulting immunosensor approach was initially tested in sera of rabbits previously inoculated with the synthetic peptide and eventually applied to the detection of ACPAs in human sera. A comparative study was carried out using control serum from a blood donor, which demonstrated the selectivity of the immunosensor response and its sensitivity for the detection of anti-CFFCP1 antibodies present in RA patients.

Topics: Animals; Antibodies, Anti-Idiotypic; Arthritis, Rheumatoid; Biosensing Techniques; Citrulline; Fibrin; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Nanotubes, Carbon; Peptides; Rabbits; Transducers

Down-regulation of fibrinolysis and increased fibrin deposition in joints are hallmarks of rheumatoid arthritis (RA), and are believed to be involved in disease progression. The mouse model of collagen-induced arthritis (CIA) closely resembles RA and has been used to explore mechanism and treatments of RA, but neither the fibrinolytic system nor pro-fibrinolytic therapies were investigated in CIA.. Plasmin activity, levels of plasminogen activator inhibitor (PAI-1), D-dimer, and IL-6 were measured in plasma of CIA mice. Fibrin deposition and PAI-1 levels were also measured in inflamed joints. Mice were treated with plasminogen activators uPA (urokinase-type plasminogen activator) or tPA (tissue-type plasminogen activator). Effects of treatment on disease severity and fibrinolytic system were assessed.. CIA caused decrease in plasmin activity, accompanied by increase in PAI-1 levels, in both blood and inflamed joints. This resulted in massive fibrin deposition in synovium. PAI-1 levels correlated negatively with plasmin activity and positively with IL-6. Treatments with uPA and tPA improved plasmin activity and removed fibrin deposits in inflamed joints. However, disease severity remained unchanged.. Fibrinolytic changes in CIA parallel changes in RA, making CIA a suitable model to study fibrinolysis in RA. Normalization of plasmin activity in CIA after treatment with plasminogen activators had no effect on disease severity.

Topics: Animals; Arthritis, Rheumatoid; Collagen; Disease Models, Animal; Disease Progression; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysin; Fibrinolysis; Immunohistochemistry; Interleukin-6; Male; Mice; Mice, Inbred DBA; Plasminogen Activator Inhibitor 1; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator

Pulmonary embolism development may be prevented if asymptomatic venous thromboembolism (VTE) can be predicted and treated preoperatively or soon after total knee arthroplasty (TKA). The purpose of this study was to evaluate whether asymptomatic VTE can be predicted by blood coagulation markers preoperatively or early after TKA. This prospective single-centre study enrolled 68 patients (6 men, 62 women; mean age: 71 years) who underwent TKA between September 2004 and August 2009. Sixteen-row multidetector computed tomography was performed 4 days before and after surgery for diagnosis of asymptomatic VTE. Blood samples were taken to measure the plasma levels of soluble fibrin monomer complex (SFMC), D-dimer and cross-linked fibrin degradation products by leukocyte elastase (e-XDP) at 4 days preoperatively, and at 1 hour, 1 day and 4 days postoperatively. The preoperative SFMC, D-dimer and e-XDP levels did not differ significantly between the thrombus (n=36) and no-thrombus (n=32) groups. D-dimer and e-XDP levels showed the most significant increases at days 4 and 1, respectively, after surgery in the thrombus group. With cut-off points of 7.5 μg/ml for D-dimer and 8.2 U/ml for e-XDP, the sensitivities were 75% and 75%, and the specificities were 63% and 59%, respectively. By multiple logistic regression analysis, D-dimer at day 4 and e-XDP at day 1 postoperatively were independent markers for early diagnosis of VTE (odds ratio=1.61 and 1.19, P=0.01 and 0.04, respectively). The postoperative occurrence of new asymptomatic VTE may be predicted by D-dimer at day 4 and e-XDP at day 1 after TKA.

Topics: Aged; Arthritis, Rheumatoid; Arthroplasty, Replacement, Knee; Biomarkers; Blood Coagulation; Early Diagnosis; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Humans; Leukocyte Elastase; Male; Multidetector Computed Tomography; Osteoarthritis, Knee; Prospective Studies; Venous Thromboembolism

The major targets of the disease-specific autoantibodies to citrullinated proteins (ACPA) in synovium of rheumatoid arthritis (RA) patients are borne by the citrullinated α- and β-chains of fibrin. We demonstrated that ACPA target a limited set of citrullinated fibrin peptides and particularly four multicitrullinated peptides which present the major epitopes. In this study, we established the clear immunodominance of the peptides α36-50Cit(38,42) and β60-74Cit(60,72,74) which were recognised by 51/81 (63%) and 61/81 (75%) of ACPA-positive patients, respectively, more than 90% recognising one, the other or both peptides. We also identified the citrullyl residues αCit(42), βCit(72) and βCit(74) as essential for antigenicity, and at a lesser degree αCit(38). Then, we assayed on overlapping 7-mer peptides encompassing the sequences of the two peptides, 3 series of sera recognising either α36-50Cit(38,42) or β60-74Cit(60,72,74) or both peptides. In each series, the reactivity profiles of the sera, largely superimposable, allowed identification of the two 4/5-mer overlapping epitopes (α: VECit(42)HQ and α': Cit(38)VVE), and the single 5-mer epitope (β: GYCit(72)ACit(74)), all located to a flexible globular domain of fibrin on a topological 3D model. In conclusion, we demonstrated that only 3 immunodominant epitopes are targeted by ACPA on citrullinated fibrin stressing their actual oligoclonality. However, the reactivity to the 3 epitopes distinguishes three subgroups of patients. The closely restricted antigen specificity suggests that the autoimmune reaction to citrullinated fibrin is antigen-driven. The accessibility of the epitopes reinforces the hypothesis of a pathogenic role for ACPA via immune complexe formation in the synovial tissue.

Topics: Antibody Specificity; Antigen-Antibody Complex; Arthritis, Rheumatoid; Autoantibodies; Autoantigens; Citrulline; Enzyme-Linked Immunosorbent Assay; Epitope Mapping; Fibrin; Humans; Immunodominant Epitopes; Models, Chemical; Peptide Fragments; Protein Conformation; Synovial Membrane

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes inflammation and, in many cases, destruction of the joints. To prevent progressive and irreversible structural damage, early diagnosis of RA is of paramount importance. The present study addresses the search of new RA citrullinated antigens that could supplement or complement diagnostic/prognostic existing tests. With this aim, the epitope anticitrullinated vimentin antibody response was mapped using synthetic peptides. To improve the sensitivity/specificity balance, a vimentin peptide that was selected, and its cyclic analogue, were combined with fibrin- and filaggrin-related peptides to render chimeric peptides. Our findings highlight the putative application of these chimeric peptides for the design of RA diagnosis systems and imply that more than one serological test is required to classify RA patients based on the presence or absence of ACPAs. Each of the target molecules reported here (fibrin, vimentin, filaggrin) has a specific utility in the identification of a particular subset of RA patients.

Topics: Aged; Amino Acid Sequence; Arthritis, Rheumatoid; Autoantibodies; Citrulline; Enzyme-Linked Immunosorbent Assay; Epitopes; Female; Fibrin; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Male; Middle Aged; Molecular Sequence Data; Peptide Library; Peptides; Peptides, Cyclic; Sensitivity and Specificity; Solid-Phase Synthesis Techniques; Vimentin

Immunogenic characteristics of filaggrin protein molecule as an antigen for antibodies to filaggrin, markers of early rheumatoid arthritis, were studied. Two new peptide motives, possible epitopes for antibodies to filaggrin, were shown in the filaggrin molecule by predictive analysis using programmed algorithms. Only IMG-3 and its cyclic form IMG-4 exhibited antigenic reactivity with sera from rheumatoid arthritis patients, differing significantly from the reactivity with donor sera. The immunogenic characteristics of IMG-3 differed from the characteristics of a previously described epitope.

Topics: Amino Acid Motifs; Amino Acid Sequence; Arthritis, Rheumatoid; Case-Control Studies; Epitope Mapping; Epitopes; Fibrin; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Molecular Sequence Data; Peptide Fragments; Protein Binding; Sequence Analysis, Protein; Sequence Homology, Amino Acid

Antibody-antigen complexes formed by IgG autoantibodies against citrullinated proteins and citrullinated forms of the alpha- and beta-chains of fibrin in rheumatoid synovial tissue play a key role in the pathophysiology of rheumatoid arthritis.. Recombinant fibrinogen was citrullinated by rabbit skeletal muscle peptidylarginine deiminase so that we could analyze the function of citrullinated fibrinogen. Namely, thrombin-catalyzed fibrin polymerization and fibrinopeptide release, protection against plasmin digestion, and factor XIIIa-catalyzed cross-linking of fibrin or fibrinogen were performed.. Strong citrullination of the Aalpha- and Bbeta-chains and weak citrullination of the gamma-chain were detected by an anti-modified citrulline detection kit. Citrullinated fibrinogen did not release FPA or FPB by thrombin catalyzation and no thrombin-stimulated conversion of fibrinogen into fibrin occurred. The citrullination of fibrinogen did not affect the 3 functions of the C-terminal gamma-chain, "a-hole," low affinity Ca binding, and gamma-gamma cross-linking.. Our functional analyses demonstrated that no thrombin-stimulated conversion of fibrinogen into fibrin occurred, because citrullinated fibrinogen did not release FPA or FPB after thrombin catalyzation. Our results and those of other reports suggest that citrullinated fibrin and fibrinogen are present in the synovium and might both be associated with the pathophysiology of RA.

Topics: Animals; Arthritis, Rheumatoid; Catalysis; Citrulline; Fibrin; Fibrinogen; Fibrinopeptide A; Fibrinopeptide B; Microscopy, Electron, Scanning; Rabbits; Thrombin

Evidence suggests that citrullinated fibrin(ogen) may be a potential in vivo target of anticitrullinated protein/peptide antibodies (ACPA) in rheumatoid arthritis (RA). We compared the diagnostic yield of three enzyme-linked immunosorbent assay (ELISA) tests by using chimeric fibrin/filaggrin citrullinated synthetic peptides (CFFCP1, CFFCP2, CFFCP3) with a commercial CCP2-based test in RA and analyzed their prognostic values in early RA.. Samples from 307 blood donors and patients with RA (322), psoriatic arthritis (133), systemic lupus erythematosus (119), and hepatitis C infection (84) were assayed by using CFFCP- and CCP2-based tests. Autoantibodies also were analyzed at baseline and during a 2-year follow-up in 98 early RA patients to determine their prognostic value.. With cutoffs giving 98% specificity for RA versus blood donors, the sensitivity was 72.1% for CFFCP1, 78.0% for CFFCP2, 71.4% for CFFCP3, and 73.9% for CCP2, with positive predictive values greater than 97% in all cases. CFFCP sensitivity in RA increased to 80.4% without losing specificity when positivity was considered as any positive anti-CFFCP status. Specificity of the three CFFCP tests versus other rheumatic populations was high (> 90%) and similar to those for the CCP2. In early RA, CFFCP1 best identified patients with a poor radiographic outcome. Radiographic progression was faster in the small subgroup of CCP2-negative and CFFCP1-positive patients than in those negative for both autoantibodies. CFFCP antibodies decreased after 1 year, but without any correlation with changes in disease activity.. CFFCP-based assays are highly sensitive and specific for RA. Early RA patients with anti-CFFCP1 antibodies, including CCP2-negative patients, show greater radiographic progression.

Topics: Arthritis, Rheumatoid; Autoantibodies; Autoantigens; Citrulline; Enzyme-Linked Immunosorbent Assay; Female; Fibrin; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Male; Middle Aged; Prognosis; Recombinant Fusion Proteins; Sensitivity and Specificity

Macrophage-derived tumor necrosis factor alpha (TNFalpha) is a dominant mediator of synovitis in rheumatoid arthritis (RA). This study was undertaken to assess whether and how immune complexes (ICs) formed by the interaction of disease-specific autoantibodies to citrullinated proteins (ACPAs) with their main synovial target antigen, citrullinated fibrin, contribute to TNFalpha production by macrophages.. An in vitro human model was developed in which monocyte-derived macrophages were stimulated with ACPA-containing ICs that were generated by capturing ACPAs from RA sera on immobilized citrullinated fibrinogen. Cellular activation was evaluated by TNFalpha assay in culture supernatants. Selective blockade of IC interactions with the 3 classes of Fcgamma receptors (FcgammaR) was used to assess the contribution of each receptor to macrophage activation. In addition, 2 citrullinated fibrin-derived peptides bearing major ACPA epitopes were tested for their capacity to inhibit formation of macrophage-activating ACPA-containing ICs.. ACPA-containing ICs induced a dose-dependent TNFalpha secretion by macrophages from 14 of 20 healthy donors. The macrophage response was systematically higher than that of the paired monocyte precursors. TNFalpha secretion was not reduced by blockade of FcgammaRI or FcgammaRIII, but was strongly repressed when interaction of ICs with FcgammaRII was prevented. The 2 citrullinated peptides significantly inhibited ACPA reactivity to citrullinated fibrinogen and, when tested together, almost completely abolished formation of macrophage-activating ICs, thereby diminishing the secreted TNFalpha levels.. Our model demonstrates the inflammatory potential of ACPA-containing ICs via engagement of FcgammaRIIa at the surface of macrophages, strongly supporting their pathophysiologic involvement. Continuing dissection of these molecular pathways could open the way to new therapeutic approaches in patients with RA.

Topics: Antigen-Antibody Complex; Antigens, CD; Arthritis, Rheumatoid; Autoantibodies; Fibrin; Fibrinogen; gamma-Globulins; Humans; Lectins, C-Type; Macrophages; Mannose Receptor; Mannose-Binding Lectins; Monocytes; Receptors, Cell Surface; Receptors, IgG; Tumor Necrosis Factor-alpha

Since aggressive therapy given early in the rheumatoid arthritis (RA) disease course has the greatest therapeutic potential, early diagnostic tests with both high specificity and sensitivity are desirable. Rheumatoid sera were found to contain antibodies against citrullinated peptides, which are considered to be highly specific markers of RA. In the present work several analogues of the alpha- and beta-chains of fibrin peptides containing different degrees of citrullination have been synthesized and analyzed by ELISA using 111 sera from RA patients. In addition, we have also investigated the synergistic effects of different presentation formats of the synthetic constructs. We have designed chimeric and cyclic peptides that bear different peptide sequences within the same molecule. Our results indicate that the synthesis of peptides bearing fibrinogen and filaggrin domains could be a robust method for the design of useful diagnostic strategies in RA.

Topics: Amino Acid Sequence; Arthritis, Rheumatoid; Autoantibodies; Citrulline; Enzyme-Linked Immunosorbent Assay; Epitopes; Fibrin; Fibrinogen; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Molecular Sequence Data; Peptides; Peptides, Cyclic

Fibrin deposition within joints is a prominent feature of arthritis, but the precise contribution of fibrin(ogen) to inflammatory events that cause debilitating joint damage remains unknown. To determine the importance of fibrin(ogen) in arthritis, gene-targeted mice either deficient in fibrinogen (Fib-) or expressing mutant forms of fibrinogen, lacking the leukocyte receptor integrin alphaMbeta2 binding motif (Fibgamma390-396A) or the alphaIIbbeta3 platelet integrin-binding motif (FibgammaDelta5), were challenged with collagen-induced arthritis (CIA). Fib- mice exhibited fewer affected joints and reduced disease severity relative to controls. Similarly, diminished arthritis was observed in Fibgamma390-396A mice, which retain full clotting function. In contrast, arthritis in FibgammaDelta5 mice was indistinguishable from that of controls. Fibrin(ogen) was not essential for leukocyte trafficking to joints, but appeared to be involved in leukocyte activation events. Fib- and Fibgamma390-396A mice with CIA displayed reduced local expression of TNF-alpha, IL-1beta, and IL-6, which suggests that alphaMbeta2-mediated leukocyte engagement of fibrin is mechanistically upstream of the production of proinflammatory mediators. Supporting this hypothesis, arthritic disease driven by exuberant TNF-alpha expression was not impeded by fibrinogen deficiency. Thus, fibrin(ogen) is an important, but context-dependent, determinant of arthritis, and one mechanism linking fibrin(ogen) to joint disease is coupled to alphaMbeta2-mediated inflammatory processes.

Topics: Amino Acid Motifs; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cartilage, Articular; Cattle; Collagen Type II; Cytokines; Fibrin; Fibrinogen; Gene Targeting; Humans; Inflammation; Joints; Leukocytes; Macrophage-1 Antigen; Male; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Knockout; Mutation

C4b-binding protein (C4BP) is a plasma oligomeric glycoprotein that participates in the regulation of complement and haemostasis. Complement-regulatory activity depends on the C4BPalpha-polypeptide, whereas the C4BPbeta-polypeptide inactivates protein S, interfering with the anti-coagulatory protein C-dependent pathway.. To investigate the expression of C4BPbeta in the rheumatoid joint.. Expression of C4BP was studied in synovial explants from patients with rheumatoid arthritis, osteoarthritis and healthy controls, using immunohistochemistry and in situ hybridisation. C4BP isoforms and free C4BPbeta were studied in synovial effusions from patients with rheumatoid arthritis, osteoarthritis and microcrystalline arthritis (MCA) by immunoblotting; total and free protein S levels were studied by enzyme immunoassay.. C4BPbeta was overexpressed in the synovial membranes of patients with rheumatoid arthritis, in close association with the severity of synovitis and the extension of interstitial fibrin deposits. As many as 85% fluids from patients with rheumatoid arthritis contained free C4BPbeta, whereas this unusual polypeptide was present in 50% fluids from patients with MCA and 40% fluids from patients with osteoarthritis. Free protein S at the effusions was pathologically reduced in patients with rheumatoid arthritis and MCA, and remained normal in patients with osteoarthritis.. C4BPbeta is expressed by the inflamed synovial tissue, where it can participate in processes of tissue remodelling associated with invasive growth.

Topics: Adult; Arthritis; Arthritis, Rheumatoid; Complement C4b-Binding Protein; Fibrin; Histocompatibility Antigens; Humans; Immunoenzyme Techniques; Osteoarthritis, Knee; Protein Isoforms; Protein S; Synovial Fluid; Synovial Membrane; Synovitis

Formation of the epitopes recognized by the rheumatoid arthritis (RA)-specific autoantibodies to citrullinated proteins (ACPA) on filaggrin and on the alpha- and beta-chains of fibrin, their synovial target, requires conversion of their arginyl residues into citrullyl residues, but is also affected by their amino-acyl environment. Using competition with five citrullinated filaggrin-derived peptides bearing major ACPA epitopes, we confirmed the close cross-reactivity between filaggrin and citrullinated fibrin. To identify the sequential epitopes recognized on fibrin by ACPA, 71 citrullinated 15-mer peptides derived from all the sites of the alpha- and beta-chains of fibrin harboring arginyl residues were tested by ELISA using ACPA-positive RA sera exhibiting different reactivity profiles to the five filaggrin peptides. We identified 18 fibrin-derived peptides bearing ACPA epitopes. Regarding the ability of fibrinogen arginyl residues to be citrullinated in vitro, 11 of the peptides likely correspond to in vivo targeted epitopes. Two out of them bear major epitopes and are located in the central globular domain of the protein. In the synovial tissue, fibrin citrullination and ACPA binding could impair fibrin degradation by plasmin. The immunological conflict between ACPA and fibrin could therefore sustain synovial inflammation not only via pro-inflammatory effector mechanisms but also via impairment of fibrinolysis.

Topics: Amino Acid Sequence; Antibody Specificity; Arthritis, Rheumatoid; Autoantibodies; Citrulline; Enzyme-Linked Immunosorbent Assay; Epitopes; Fibrin; Fibrinogen; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Models, Molecular; Molecular Sequence Data; Protein Structure, Quaternary

With the aim of developing a new enzyme-linked immunosorbent assay test to detect autoantibodies in the sera of rheumatoid arthritis patients with a high sensitivity and specificity using synthetic citrullinated peptides of fibrin (which is abundant in rheumatoid synovium) as antigenic substract, peptides belonging to alpha- and beta-fibrin chains were selected by computer-aided prediction of antigenicity and epitope mapping and synthesized in solid phase. We analysed by enzyme-linked immunosorbent assay 133 sera from patients with well-characterized rheumatic diseases, including 67 patients with rheumatoid arthritis. The results of the immunoassays reported highlight the usefulness of fibrin-related peptides in rheumatoid arthritis diagnosis and, especially, the ability and specificity of the [Cit(621,627,630)]alpha-fibrin(617-631) (alpha fib617) peptide sequence to recognize the autoantibodies that are present in rheumatoid arthritis patients.

Topics: Amino Acid Sequence; Arthritis, Rheumatoid; Chromatography, High Pressure Liquid; Citrulline; Enzyme-Linked Immunosorbent Assay; Epitope Mapping; Fibrin; Filaggrin Proteins; Humans; Immunodominant Epitopes; Intermediate Filament Proteins; Molecular Sequence Data; Peptide Fragments; Peptides, Cyclic; Sensitivity and Specificity; Sequence Analysis, Protein

Peptidylarginine deiminases (PADIs) convert peptidylarginine into citrulline via post-translational modification. Anti-citrullinated peptide antibodies are highly specific for rheumatoid arthritis (RA). Our genome-wide case-control study of single-nucleotide polymorphisms found that the PADI4 gene polymorphism is closely associated with RA. Here, we localized the expression of PADI4 and the citrullinated protein product in synovial RA tissue.. We used immunohistochemistry, double immunofluorescent labelling and western blotting.. We found that PADI4 is extensively expressed in T cells, B cells, macrophages, neutrophils, fibroblast-like cells and endothelial cells in the lining and sublining areas of the RA synovium. We also found extracellular and intracellular expression of PADI4 in fibrin deposits with loose tissue structures where apoptosis was widespread. Unlike PADI4, citrullinated protein generally appeared in fibrin deposits that were abundant in the RA synovium. The citrullinated fibrin aggregate was immunoreactive against immunoglobulin (Ig) A and IgM, but not IgG and IgE. Although a little PADI4 was expressed in osteoarthritic and normal synovial tissues, significant citrullination was undetectable.. The results showed that PADI4 is mainly distributed in cells of various haematopoietic lineages and expressed at high levels in the inflamed RA synovium. The co-localization of PADI4, citrullinated protein and apoptotic cells in fibrin deposits suggests that PADI4 is responsible for fibrin citrullination and is involved in apoptosis. The immunoreactivity of citrullinated fibrin with IgA and IgM in the RA synovium supports the notion that citrullinated fibrin is a potential antigen of RA autoimmunity.

Topics: Apoptosis; Arthritis, Rheumatoid; Blotting, Western; Citrulline; Fibrin; Humans; Hydrolases; Immunophenotyping; Leukocytes; Osteoarthritis; Protein-Arginine Deiminase Type 4; Protein-Arginine Deiminases; Synovial Membrane

In the rheumatoid synovium, deiminated ('citrullinated') forms of fibrin are the major targets of IgG autoantibodies to citrullinated proteins (ACPA), the most specific serological markers of rheumatoid arthritis (RA). To further the characterization of ACPA, we determined their subclass distribution. From a previously validated highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) onto in vitro deiminated human fibrinogen - antihuman fibrin(ogen) autoantibodies (AhFibA)-ELISA - we derived and calibrated four ELISAs, using monoclonal antibodies to each of the four IgG subclasses, to determine the proportions of AhFibA subclasses in the sera. A series of 186 serum samples from RA patients was analysed. All AhFibA-positive sera contained IgG1-AhFibA, which reached the highest titres and accounted for more than 80% of AhFibA in three-quarters of the sera. One or two other subclasses were associated with IgG1 in 39% of the sera, IgG4-AhFibA being observed much more frequently and at higher titres than IgG3- or IgG2-AhFibA. IgG1 alone or IgG(1 + 4)-AhFibA were the AhFibA subclass profiles found in more than 80% of patients. AhFibA are mainly IgG1 and, to a lesser extent, IgG4. Such IgG subclass profiles may influence the effector phases of the immunological conflict between ACPA and deiminated fibrin that takes place specifically in the rheumatoid synovium and therefore may play a critical role in the self-maintenance of rheumatoid inflammation.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Analysis of Variance; Arthritis, Rheumatoid; Autoantibodies; Biomarkers; Citrulline; Enzyme-Linked Immunosorbent Assay; Female; Fibrin; Fibrinogen; Humans; Immunoglobulin G; Male; Middle Aged

Autoantibodies to deiminated (citrullinated) proteins are the most specific serological markers of rheumatoid arthritis (RA). Deimination is critical in generating the peptidic epitopes they recognize. In the synovial tissue (ST), deiminated forms of the alpha- and beta-chains of fibrin are their major autoantigenic targets (anti-human fibrin(ogen) autoantibodies (AhFibA)). We investigated whether the presence of deiminated fibrin in the ST was specific for RA, because this could explain why AhFibA are RA specific. In 13 patients with RA and 19 patients with various other rheumatological disorders, knee ST biopsies were collected in macroscopically inflamed areas identified under arthroscopy. Synovitis was histopathologically confirmed in all of the biopsies. By immunoblotting, using antisera to fibrin, Abs to citrullyl residues, and AhFibA purified from RA sera, deiminated fibrin was evidenced in ST extracts from all of the patients. Moreover, variations in the degree of fibrin deimination were observed that were not related to the disease. Immunohistochemical analysis, using Abs to citrullyl residues and an antiserum to fibrin on adjacent serial sections of ST, confirmed the results because deiminated proteins colocalized with fibrin in RA as well as in control patients. Therefore, fibrin deimination in the ST is a general phenomenon associated to any synovitis, which does not necessarily induce a B autoimmune response with production of AhFibA.

Topics: Adult; Aged; Antibody Specificity; Arthritis, Rheumatoid; Autoantibodies; Autoantigens; Case-Control Studies; Citrulline; Epitopes; Female; Fibrin; Humans; Male; Middle Aged; Models, Immunological; Synovial Membrane; Synovitis

Fibrin deposits adhered to the synovial surface are typical of rheumatoid joints. Since fibrin appears to have a role in arthritis perpetuation our aim was to investigate how these deposits are formed and the consequences of their adhesion to the tissue.. The appearance of fibrin aggregates either free in the synovial fluid or attached to the membrane was studied in rabbits with antigen-induced arthritis by histological techniques at different time points from challenge. In the fixed synovial membranes areas of fibrin-bound synovium were evaluated by qualitative variables to obtain a sequential profile of morphological changes.. Fibrin aggregates appeared from the initial stages of the disease in the synovial effusion. Later on, they were localized on the synovial surface and progressive changes were noted at the fibrin-tissue interface, ending with the invasion of the aggregates by synovial cells and their incorporation into the tissue.. Fibrin aggregates generated inside the joint cavity may constitute a source of activation and acquisition of invasiveness of the synovial fibroblasts, a process to explore within the perpetuating mechanisms of rheumatoid arthritis.

Topics: Animals; Arthritis, Rheumatoid; Fibrin; Fibrinogen; Fibroblasts; Fibronectins; Hindlimb; Immunohistochemistry; Models, Animal; Ovalbumin; Rabbits; Synovial Fluid; Synovial Membrane; Synovitis; Time Factors; Tissue Adhesions

Clinical and experimental evidence suggests that extravascular fibrin deposition in arthritic joints is prominent and deleterious. The aim of this study was to investigate the contributions of tissue factor (TF) and its inhibitor, TF pathway inhibitor (TFPI), in arthritis.. Synovial tissue specimens obtained from 10 patients with rheumatoid arthritis (RA) and 12 patients with osteoarthritis (OA) were scored histologically for inflammation and fibrin content. TF and TFPI levels were assayed at antigenic and functional levels. TF messenger RNA (mRNA) levels were determined using RNase protection assays. The effect of TF inhibition in murine antigen-induced arthritis (AIA) was assessed by administering systemically active site-blocked activated factor VIIa (FVIIai).. Functional TF activity was significantly increased in synovial membranes from RA patients compared with those from OA patients. In contrast, no difference in TF mRNA and TF antigenic levels was observed between these 2 groups. This discrepancy can be accounted for by TFPI, because we observed a negative correlation between TF activity and TFPI activity. There was a significant difference between the RA and OA groups in terms of synovial inflammation, with more inflammation observed in the RA group. Most importantly, TF activity was associated with fibrin (P = 0.024) and with histologic inflammation (P = 0.03) scores. In AIA, inhibition of TF-induced coagulation by FVIIai led, on day 9 of arthritis, to decreased synovial thickness and decreased articular cartilage damage, although only the latter difference between controls and treated mice reached significance (P < 0.04). Finally, in FVIIai-treated mice, there was a strong negative association between the prothrombin time and intraarticular fibrin deposition.. Our results show that TF expression in arthritic synovial tissue favors extravascular coagulation and may play a role in inflammation in RA. In this context, TF inhibitors may be of therapeutic value.

Topics: Aged; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Dansyl Compounds; Disease Models, Animal; Factor VIIa; Female; Fibrin; Fibrinolytic Agents; Hindlimb; Humans; Immunohistochemistry; Lipoproteins; Male; Mice; Mice, Inbred C57BL; Middle Aged; Osteoarthritis; Radionuclide Imaging; RNA, Messenger; Synovitis; Thromboplastin

Activation of coagulation and fibrinolysis play a role in the pathophysiology of experimental arthritis.. To determine the extent of activation of the coagulation and fibrinolytic pathways in different joint diseases in humans and to ascertain the factors that may influence fibrin deposition within the joint.. Plasma from normal subjects (controls, n= 21) and plasma and synovial fluid samples from patients with rheumatoid arthritis (RA; n = 64), osteoarthritis (OA; n = 29), spondyloarthropathy (SpA; n = 22) and crystal arthritis (CA; n = 25) were analyzed for the levels of TF (tissue factor) and tissue factor pathway inhibitor (TFPI) activities, thrombin-antithrombin III (TAT) complexes, and F1 + 2 (thrombin fragment), fibrin d-dimer and thrombin-activated fibrinolysis inhibitor (TAFI) antigenic levels. The measurements were analyzed by pairwise correlation with each other as well as with standard parameters of inflammation [C-reactive protein (CRP), joint leukocyte count]. Inter-group comparisons were performed to look for disease-specific differences.. Compared with healthy controls, patients with joint diseases had higher levels of TAT, F1 + 2 and d-dimers in their plasma. In the synovial fluid, TF activity, TAT, d-dimers, and TAFI were significantly higher in inflammatory arthritides than in OA. The levels were highest in RA patients. In the plasma, TF activity was correlated with TAT and d-dimer levels with CRP, TFPI, and TAT. In the synovial fluid, TF activity correlated with plasma CRP levels, synovial fluid leukocyte count, and synovial TAT and TAFI levels. In addition, synovial d-dimers correlated with CRP, and synovial TAFI levels were correlated with synovial F1 + 2 and TAT.. Activation of the coagulation and fibrinolytic cascades in the joint and in the circulation is evident in both inflammatory and degenerative joint diseases. Within the joint, inflammatory mechanisms leading to TF-mediated activation of the coagulation pathway and subsequent fibrin deposition is the most likely explanation for the observed findings. In the plasma, the link between inflammation (CRP increase) and TF activation is weak, and a non-TF-mediated mechanism of coagulation activation could explain these findings. RA is characterized by significantly higher levels of TAT in the synovial fluid and plasma than other arthritides. Although fibrinolytic activity is linked to inflammation, the increased amounts of TAFI in the joint, particularly in RA, may explain why fibrin formation is so prominent in this condition compared with other joint diseases.

Topics: Adult; Aged; Arthritis; Arthritis, Rheumatoid; Biomarkers; Blood Coagulation; Carboxypeptidase B2; Case-Control Studies; Female; Fibrin; Fibrinolysis; Humans; Inflammation; Linear Models; Male; Middle Aged; Osteoarthritis; Spondylitis, Ankylosing; Synovial Fluid

To examine the role of plasminogen activator inhibitor type-1 (PAI-1), the major fibrinolytic inhibitor, in vivo during murine antigen-induced arthritis (AIA).. AIA was induced in PAI-1-deficient mice and control wild-type mice. Arthritis severity was evaluated by technetium 99m (99mTc) uptake in the knee joints and by histological scoring. Intra-articular fibrin deposition was examined by immunohistochemistry and synovial fibrinolysis quantitated by tissue D-dimer measurements and zymograms.. Joint inflammation, quantitated by 99mTc uptake, was significantly reduced in PAI-1(-/-) mice on day 7 after arthritis onset (P<0.01). Likewise, synovial inflammation, evaluated by histological scoring, was significantly decreased in PAI-1-deficient mice on day 10 after arthritis onset (P<0.001). Articular cartilage damage was significantly decreased in PAI-1(-/-) mice, as shown by histological grading of safranin-O staining on day 10 after arthritis onset (P<0.005). Significantly decreased synovial accumulation of fibrin was observed by day 10 in arthritic joints of PAI-1(-/-) mice (P<0.005). Accordingly, the synovial tissue content of D-dimers, the specific fibrin degradation products generated by plasmin, were increased in PAI-1(-/-) mice (P<0.02). Finally, as expected, PA activity was increased in synovial tissues from PAI-1(-/-) mice, as shown by zymographic analysis.. These results indicate that deficiency of PAI-1 results in increased synovial fibrinolysis, leading to reduced fibrin accumulation in arthritic joints and reduced severity of AIA.

Topics: Animals; Antigens; Arthritis, Rheumatoid; Disease Models, Animal; Fibrin; Fibrinolysis; Knee Joint; Mice; Mice, Inbred C57BL; Mice, Knockout; Plasminogen Activator Inhibitor 1; Synovial Membrane; Technetium

IgG antifilaggrin autoantibodies (AFA) are the most specific serological markers of rheumatoid arthritis. In epithelial tissues, they recognize citrulline-bearing epitopes present on various molecular forms of (pro)filaggrin. Histological analysis of rheumatoid synovial membranes with an Ab to citrulline showed labeling of interstitial amorphous deposits and mononuclear cells of various types. Immunochemical analysis of exhaustive sequential extracts of the same tissues showed that they contain several deiminated (citrulline containing) proteins. Among them, two proteins, p64--78 and p55--61, present in urea-DTT and guanidine extracts, were shown by immunoblotting to be specifically targeted by AFA. By amino-terminal sequencing the proteins were identified as deiminated forms of the alpha- and beta-chains of fibrin, respectively. Their identity was confirmed using several Abs specific for the A alpha- and/or to the B beta-chain of fibrin(ogen). Moreover, AFA-positive rheumatoid arthritis (RA) sera and purified AFA were highly reactive to the A alpha- and B beta-chains of human fibrinogen only after deimination of the molecules by a peptidylarginine deiminase. Autoantibodies affinity purified from a pool of RA sera onto deiminated fibrinogen were reactive toward all of the epithelial and synovial targets of AFA. This confirmed that the autoantibodies to the deiminated A alpha-and B beta-chains of fibrinogen, the autoantibodies to the synovial proteins p64--78 and p55--61, and, lastly, AFA, constitute largely overlapping autoantibody populations. These results show that deiminated forms of fibrin deposited in the rheumatoid synovial membranes are the major target of AFA. They suggest that autoimmunization against deiminated fibrin is a critical step in RA pathogenesis.

Topics: Animals; Antigen-Antibody Reactions; Arthritis, Rheumatoid; Autoantibodies; Autoantigens; Epitopes; Fibrin; Fibrinogen; Filaggrin Proteins; Humans; Imines; Immunohistochemistry; Intermediate Filament Proteins; Peptide Fragments; Rats; Synovial Membrane

We evaluated histologically samples of synovial tissue from the knees of 50 patients with rheumatoid arthritis (RA). The samples were taken during revision for aseptic loosening. The findings were compared with those in 64 knees with osteoarthritis (OA) and aseptic loosening and in 18 knees with RA without loosening. The last group had been revised because of failure of the inlay or the coupling system of a constrained prosthesis. All the patients had had a total ventral synovectomy before implantation of the primary prosthesis. In all three groups a foreign-body reaction and lymphocellular infiltration were seen in more than 80% of the tissue samples. Deposits of fibrin were observed in about one-third to one-half of the knees in all groups. Typical signs of the reactivation of RA such as rheumatoid necrosis and/or proliferation of synovial stromal cells were found in 26% of knees with RA and loosening, but not in those with OA and loosening and in those with RA without loosening. Our findings show that reactivation of rheumatoid synovitis occurs after total knee replacement and may be a cofactor in aseptic loosening in patients with RA.

Topics: Aged; Arthritis, Rheumatoid; Female; Fibrin; Foreign-Body Reaction; Humans; Knee Prosthesis; Lymphocytes; Male; Middle Aged; Osteoarthritis; Prosthesis Failure; Recurrence; Reoperation; Synovitis

Extravascular coagulation and diminished fibrinolysis are processes that contribute to the pathology of both inflammatory arthritis and atherosclerosis. We hypothesized that, given its homology with plasminogen, apolipoprotein (apo) (a), the distinctive glycoprotein of the atherogenic lipoprotein (Lp) (a), may be equally implicated in inflammatory arthritis. We detected the presence of apo(a) as part of Lp(a) in human arthritic synovial fluid. The abundance of apo(a) in synovial fluid rose in proportion to plasma apo(a) levels and was higher in inflammatory arthritides than in osteoarthritis. In addition, apo(a) immunoreactive material, but not apo(a) transcripts, was detected in inflammatory arthritic synovial tissues. These data indicated that synovial fluid apo(a) originates from circulating Lp(a) and that diffusion of Lp(a) through synovial tissue is facilitated in inflammatory types of arthritis. In synovial tissues, apo(a) co-localized with fibrin. These observations could be reproduced in a model of antigen-induced arthritis, using transgenic mice expressing human Lp(a). Although in this mouse model the presence of apo(a) did not change the severity of arthritis, the co-localization of apo(a) with fibrin in synovial tissue suggests that, in humans, apo(a) may modulate locally the fibrinolytic activity and may thus contribute to the persistence of intra-articular fibrin in inflammatory arthritis.

Topics: Animals; Antigens; Apolipoproteins A; Arthritis; Arthritis, Rheumatoid; Fibrin; Humans; Joints; Lipoprotein(a); Mice; Mice, Transgenic; Osteoarthritis; Particle Size; Synovial Fluid; Synovial Membrane

The aim of this study was to investigate the expression and localization of cyclooxygenase-1 and -2 (COX-1 and COX-2) in synovial tissues from patients with rheumatoid arthritis (RA). Synovial tissues from 9 patients with RA and 5 patients with osteoarthritis (OA) were examined for COX-1 and COX-2 expressions by immunohistochemical staining using 2 polydonal COX-1 and COX-2 antibodies. In RA synovia, synovial lining cells showed intense immunostaining for COX-1, whereas slight to moderate staining was observed in inflammatory cells, stromal fibroblast-like cells and vascular endothelial cells. There was no significant difference in COX-1 expression between RA and OA synovia. The localization of COX-2 expression dearly differed from that of COX-1 expression, being most intense in inflammatory cells. However, there was no difference in COX-1 and COX-2 expressions between RA and OA synovial tissues. Our observations support that inflammatory mechanisms modulated by COX-1 and COX-2 in chronic RA synovium might be similar to those in chronic OA synovium.

Topics: Adult; Aged; Arthritis, Rheumatoid; Cell Division; Cyclooxygenase 1; Cyclooxygenase 2; Female; Fibrin; Humans; Isoenzymes; Male; Membrane Proteins; Middle Aged; Neutrophil Infiltration; Osteoarthritis; Prostaglandin-Endoperoxide Synthases; Stromal Cells; Synovial Membrane

To determine the effect of the thrombin inhibitor, hirudin, on the pathogenesis of murine antigen induced arthritis (AIA).. AIA was induced by intra-articular injection of methylated bovine serum albumin in the knee joints of previously immunised mice. Hirudin (injected subcutaneously 3 x 200 microg/mouse/day) was given over 13 days, starting three days before arthritis onset, and its anticoagulant effect monitored by clotting times. Arthritis severity was evaluated by technetium-99m ((99m)Tc) uptake in the knee joints and by histological scoring. In addition, intra-articular fibrin deposition was examined by immunohistochemistry, and synovial cytokine mRNA expression measured by RNase protection.. Joint inflammation, measured by (99m)Tc uptake, was significantly reduced in hirudin treated mice at days 7 and 10 after arthritis onset. Histologically, synovial thickness was markedly decreased in hirudin treated mice compared with untreated ones. By contrast, no difference in articular cartilage proteoglycan content was found between both groups. Intra-articular fibrin deposition and synovial interleukin 1beta mRNA levels, were slightly reduced ( approximately 20%) in arthritic joints from hirudin treated mice compared with untreated ones at day 10 of AIA.. Hirudin reduces joint inflammation associated with AIA by fibrin-dependent and independent mechanisms.

Topics: Animals; Antithrombins; Arthritis, Rheumatoid; Cytokines; Drug Evaluation, Preclinical; Fibrin; Hirudin Therapy; Interleukin-1; Mice; Mice, Inbred C57BL; Proteoglycans; Severity of Illness Index; Synovitis; Technetium; Treatment Outcome

It has long been recognized that in most inflamed arthritic joints the coagulation system is activated, leading to the local generation of fibrin, and it has long been hypothesized that the local fibrin deposition promotes inflammation and tissue destruction. However, only recently has the direct effect of fibrin on the inflammatory process been seriously investigated, and specific roles assigned to fibrin or its products as mediators of the inflammatory process. Although fibrin and/or fibrinogen (fibrin(ogen)) is abundantly present in inflamed tissues and joints rich in fibroblastic cells, no significant data on fibrin(ogen)-induced gene expression by fibroblasts have been published. We now demonstrate that coculture of human synovial fibroblasts with fibrin(ogen) results in the up-regulation of ICAM-1 as well as increased production of the chemokines IL-8 and growth-related oncogene-alpha. Increased ICAM-1 expression was fibrin(ogen) dose-dependent and was demonstrated by ELISA, flow cytometry, and functional adhesion assays. Levels of ICAM-1 induced by fibrin(ogen) were comparable to those that could be induced by cytokine stimulation. Fibrin(ogen) stimulation of ICAM-1 could be suppressed by pyrrolidinedithiocarbamate, an inhibitor of NF-kappaB activation. Chemokine production was induced by fibrin(ogen) in cell culture supernatants >100-fold as compared with controls. Thus, through its activation of synovial fibroblasts, fibrin(ogen) deposition may promote the recruitment (via chemokines) and retention (via adhesion molecules) of lymphocytes within the arthritic joint.

Topics: Antioxidants; Arthritis, Rheumatoid; Cell Adhesion; Cells, Cultured; Chemokines; Drug Synergism; Female; Fibrin; Fibrinogen; Fibroblasts; Humans; Intercellular Adhesion Molecule-1; Male; Pyrrolidines; Synovial Membrane; T-Lymphocytes; Thiocarbamates; Thrombin

Increased concentrations of lipid peroxidation products have been described in the serum and synovial fluid from patients with rheumatoid arthritis. A large proportion of the unsaturated lipids in human extracellular fluids is a component of low density lipoprotein (LDL). The oxidative modification of LDL, and its subsequent uptake by macrophages, has been implicated in the pathogenesis of atherosclerosis, but not of rheumatoid arthritis. This study aimed to assess whether oxidatively modified LDL was present in the rheumatoid synovium.. A polyclonal antiserum raised in rabbits against oxidised LDL (o-LDL) was used to perform an immunohistochemical study of a series of synovial biopsy specimens from patients with rheumatoid arthritis.. Collections of positively stained macrophages, arranged in a linear fashion and with the morphological characteristics of foam cells--that is, 'fatty streaks', were identified around blood vessels within the intimal connective tissue. In addition, scattered, positively stained foam cells were present in association with deposits of fibrin. These staining patterns were absent from control synovial membranes (traumatic knee injuries).. The findings in all rheumatoid patients studied suggest that atherosclerosis and rheumatoid arthritis have analogous pathogenetic features.

Topics: Arthritis, Rheumatoid; Fibrin; Foam Cells; Humans; Immunoenzyme Techniques; Lipoproteins, LDL; Oxidation-Reduction; Synovial Membrane

To determine the clinical significance of the microscopic study of the synovial fluid (SF) sediment, 306 sediments were examined from 216 patients with the most frequently occurring acute and chronic arthropathies. The SF was obtained using a fine gauge needle. Microscopic rice bodies were seen in 53 (17.3%) of the samples studied. Forty-five (84.9%) of the samples in which rice bodies were observed were from patients with rheumatoid arthritis (RA) (p < 0.001); 34.9% of the 129 RA samples were found to contain rice bodies. The specificity of finding rice bodies in RA was 95.5%. Most rice bodies were composed of partly or totally hyalinized fibrinous material; in their interior, mononuclear cells were predominantly observed--most of them macrophagic in appearance. With less frequency the rice bodies exhibited central areas of fibrosis. Our results suggest that microscopic rice bodies are fibrinous particles derived from the entrapping of cells in the dense fibrin network present in inflammatory SF.

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Inclusion Bodies; Microscopy, Electron; Retrospective Studies; Synovial Fluid

Immunohistochemical techniques were applied to rheumatoid synovium in order to detect components of coagulation and fibrinolysis pathways within these tissues. These techniques revealed an intact coagulation pathway and plasminogen activator inhibitor-2 associated with macrophage-like cells that were present throughout these tissues, especially in subsurface areas. Cell-associated thrombin generation appeared to account for conversion of abundant fibrinogen to fibrin. Occasional macrophage-like cells also stained for urokinase but tissue-type plasminogen activator and plasminogen activator inhibitor-1 were restricted to vascular endothelium. Intense synovial fibrin deposition (with the limited evidence for associated fibrinolysis) may contribute to local inflammation and explain certain clinical features of rheumatoid arthritis. These findings suggest novel treatment hypotheses for this disease.

Topics: Arthritis, Rheumatoid; Blood Coagulation Disorders; Factor V; Factor VII; Factor X; Factor XIII; Fibrin; Fibrinogen; Humans; Immunohistochemistry; Macrophages; Plasminogen Inactivators; Synovial Membrane; Thromboplastin

Fibrin deposition is a prominent finding in the synovium of patients with rheumatoid arthritis (RA). Macrophages are found in increased numbers in RA synovium, and these cells are known to produce a variety of procoagulant and anticoagulant molecules. Using immunohistologic techniques, the content and distribution of several important components of the coagulation system in the synovium of patients with RA, osteoarthritis (OA), or traumatic joint abnormalities requiring surgery were investigated. Samples from 3 patients from each category were examined in detail. RA synovium (compared with that of patients with OA or joint trauma) had increased numbers of macrophages and increased expression/content of fibrinogen, tissue factor, factor XIII, tissue transglutaminase, cross-linked fibrin (fibrin D dimer), urokinase-type plasminogen activator, and alpha 2-plasmin inhibitor. Macrophage content in RA synovium was increased in both the lining cell areas and the interstitial cell areas. Fibrinogen was distributed throughout the tissue in all samples and was greater in RA synovium. In trauma and OA synovia, tissue factor was seen only in association with vessels (endothelial cells), but in RA synovium, it was markedly increased throughout the tissues. While fibrin D dimer was seen in small amounts in synovial lining cell areas of trauma and OA synovia, it was present in increased amounts in the lining cell and interstitial cell areas of RA synovium. Factor XIII and tissue transglutaminase were present in scant amounts in trauma and OA synovia, but there were increased amounts of both (especially tissue transglutaminase) in RA synovium in the vessel, lining cell, and interstitial cell areas. Urokinase and alpha 2-plasmin inhibitor were also markedly increased in RA synovium. These results suggest that in inflamed synovium, there is ongoing extravascular tissue fibrin formation and dissolution that correlates with the degree of inflammation and macrophage content. Extravascular coagulation/fibrinolysis in RA represents a potential target for therapeutic intervention in this disease.

Topics: alpha-2-Antiplasmin; Arthritis, Rheumatoid; Factor XIII; Fibrin; Fibrinogen; Fibrinolytic Agents; Humans; Immunohistochemistry; Macrophages; Osteoarthritis; Plasminogen Activators; Synovial Membrane; Thromboplastin; Transglutaminases; Urokinase-Type Plasminogen Activator

Nodules obtained from five patients with classical seropositive rheumatoid arthritis were studied by an immunofluorescence technique using polyclonal antibodies to IgG, IgA, IgM, C3c, and fibrin, and monoclonal antibodies to the terminal (C5b-9) complement complex (reaction with a neoantigen in C9 revealed during activation), DR antigens, T cells, macrophages, and interdigitating cells. In all instances the central necrotic areas stained strongly for fibrin and more weakly for IgG, IgA, IgM, C3, and terminal complement complex. The surrounding palisading cells reacted with antibodies to DR and macrophages. In the peripheral granulomatous tissue most of the lymphocytes reacted with the antibodies to T cells, whereas various amounts of the larger mononuclear cells were stained by antibodies to DR antigens, macrophages, and interdigitating cells. In all instances the walls of some of the smaller vessels in the granulomatous tissue stained for fibrin, C3, and terminal complement complex. Plasma cells were not seen except for scattered IgM cells in one nodule. These results support the view that the palisading cells are derived from macrophages, and indicate that there is vasculitis with activation of C3 and the terminal complement pathway in the granulomatous tissue.

Topics: Arthritis, Rheumatoid; Autoantigens; Complement C3c; Fibrin; Fluorescent Antibody Technique; HLA-DR Antigens; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Immunoglobulins; Macrophages; Rheumatoid Nodule; T-Lymphocytes

Erythrocyte CR1, a C3b/C4b-binding complement-regulatory protein, is sensitive to proteolysis in vitro. To test the hypothesis that in vivo erythrocyte CR1 reduction results from intravascular proteinase activities, we used enzyme-linked immunosorbent assays to measure gamma-crosslinked fibrin degradation products (D-dimers) as indicators of coagulation/fibrinolytic activity, and complexes of neutrophil elastase with alpha 1 proteinase inhibitor (E/A) as indicators of neutrophil enzyme release in malignant and inflammatory disorders. Erythrocyte CR1, measured by monoclonal anti-CR1 antibody binding, was inversely related to disease activity and blood proteinase markers. Levels of erythrocyte CR1 were significantly lower for patients with active versus remittent squamous and small cell lung cancers, Hodgkin's and diffuse large cell lymphomas, and acute myelogenous leukemias. In patients with active thoracic cancers, elevated D-dimer levels correlated with reduction of CR1. In patients with rheumatoid arthritis, CR1 reduction was correlated with elevated levels of elastase complexes. Our findings substantiate the relationship of acquired CR1 reduction to the activity of certain diseases and provide circumstantial support for the hypothesis that erythrocyte CR1 is lost to proteolysis in vivo. Although heritable differences in CR1 expression reduce the interpretability of single measurements of erythrocyte CR1 levels, disease-associated CR1 reduction may be a useful indicator of disorders with chronically increased blood proteinase activity.

Topics: Adult; Aged; Arthritis, Rheumatoid; Biomarkers; Carcinoma, Small Cell; Erythrocyte Membrane; Fibrin; Humans; Lung Neoplasms; Middle Aged; Peptide Hydrolases; Receptors, Complement

Synovial biopsies were obtained from 28 patients with various kinds of chronic arthritis, at synovectomy and 6 and 12 months later. The tissues were examined by immunofluorescence technique, recording the quantities of cells and extracellular deposits staining with polyclonal antisera to IgG, IgA, IgM, C3c, fibrinogen, and chi and lambda light chains, and monoclonal antibodies to CD3, CD5, CD11b, HLA DR, and TCC (Terminal Complement Complex). These parameters were compared with scores obtained by arthroscopy and clinical evaluation (Colorado Knee Score) performed at the same time. Taken as a group, the immunological parameters showed reduction in activity 6 months after synovectomy (p less than 0.01), and a tendency to revert to base-line values after 12 months. A similar reduction in activity after 6 months was also found by arthroscopic and clinical evaluation. Thus, this longitudinal study demonstrated a relationship between changes in immunologic activity, arthroscopic findings and clinical activity after synovectomy in patients with chronic arthritis. This is consistent with an immunological pathogenesis for the inflammation in these joints.

Topics: Adolescent; Adult; Antigens, CD; Arthritis, Juvenile; Arthritis, Psoriatic; Arthritis, Rheumatoid; Arthroscopy; Child; Female; Fibrin; Fibrinogen; Fluorescent Antibody Technique; HLA-DR Antigens; Humans; Immunoglobulins; Male; Middle Aged; Prospective Studies; Synovectomy; Synovial Membrane; Synovitis

The enzymatic, nonenzymatic and XIIa-dependent fibrinolysis was inhibited. In RA without systemic manifestations the main cause of appearance of soluble complexes of monomeric fibrins (SCMF) in the blood is a local activation of coagulation in the inflamed joint tissues. It is suggested that an increase of SCMF concentration in the blood in patients with RA is a reliable and dynamic index of the activity of the inflammatory process.

Topics: Adult; Aged; Arthritis, Rheumatoid; Combined Modality Therapy; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Humans; Male; Middle Aged

The clinical feature of rheumatoid arthritis (RA) is characterized by systemic-immunological, local-inflammatory phenomena. But it is the joint destruction which gives RA its dramatic course. Through the years we evaluated joint tissues of app. 14,500 patients with defined RA and besides the conventional inflammatory processes we could prove a mechanism which is responsible for the joint destruction and which is typical for RA. Following an exudative episode, compact, homogeneous cell masses can occur in the synovial membrane which consist of macronuclear, immature, synoviogenous cells. These masses can encroach on the adjacent structures of articular cartilage and subchondral bone which consequently enzymatically will be degraded and destroyed. Since these rapidly growing cell masses are avascular in their aggressive stage, they soon will collapse. The surviving cells "modulate" to fibroblast which start collagen synthesis and thus form the well-known pannus. In the area of the compact, homogeneous cell masses of synovial origin, there are no lymphocytes and plasma cells nor PMN or macrophages. Macrophages only occur after the breakdown of the cell masses and the beginning of pannus formation, this also is the case with lymphocytes and plasma cells. Thus, the immature synoviogenous cell masses are in contrast to the initial synovitis not of inflammatory character. Their cytological and aggressive behavior rather shows oncological analogies. This also corresponds to our proof of the expression of myc and ras to a high degree in the aggressive cell masses in RA.

Topics: Arthritis, Rheumatoid; Cell Division; Fibrin; Humans; Joints; Neoplasms; Synovial Fluid; Synovial Membrane

Topics: Adult; Arthritis, Rheumatoid; Collagen Diseases; Factor XIII; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Raynaud Disease

In mice immunized with bovine fibrin, the same antigen was applied to the pleural cavity. A granulomatous pleuritis appeared affecting both the visceral and the parietal pleura, especially located around the antigen particle. Rheumatoid arthritis (RA) cells were constantly found in the pleural cavity when pleural lesions were present. This immunological, granulomatous pleuritis is the first experimental model for the study of RA cell-positive types of pleurisy in humans.

Topics: Animals; Arthritis, Rheumatoid; Disease Models, Animal; Fibrin; Granulocytes; Inclusion Bodies; Lung; Male; Mice; Mice, Inbred BALB C; Pleura; Pleural Effusion; Pleurisy

The meniscal surfaces from patients with and without inflammatory joint diseases were investigated for the presence of superficially located polymorphonuclear granulocytes (PMNs). In histochemically stained tissue sections as well as in electron microscopic investigations on previously paraffin-embedded menisci, PMNs were observed in cases with inflammatory rheumatoid joint diseases. The inflammatory cells were located in fibrin adhering to the meniscal surface and in the fibrous meniscal tissue just beneath the fibrin. From these observations it is concluded that PMNs in the inflammatory synovial fluid may gain access to the fibrous structures of the joint, thus participating in tissue destruction, as has been assumed from in vitro investigations by other authors.

Topics: Arthritis, Rheumatoid; Fibrin; Humans; Joint Diseases; Menisci, Tibial; Microscopy, Electron; Neutrophils; Staining and Labeling; Synovial Membrane

In 50 patients suffering for 1-15 years from rheumatoid arthritis, needle-biopsy of the synovial membrane was carried out. The finding correlated with the general clinical activity of the disease. Each type of histological change was evaluated with regard to its diagnostic value in assessing clinical activity. Among the histological changes, oedema, synovial cell proliferation, lymphocyte-plasma cell proliferation and necrotic vasculitis showed a negative correlation with clinical activity, while a positive correlation was observed between clinical activity and the presence of fibrin (fresh and old), fibrinoid, fibrinoid basophilia, fibroblast proliferation, synovial cell desquamation, concentric perivascular sclerosis, fibrosis and hyalinosis. Vascular changes of the synovial membrane such as oedema, fresh fibrin exudate, necrotic vasculitis showed a negative correlation with clinical activity while hyalinization and concentric sclerosis and clinical activity were found to be in positive correlation. It is concluded that in the course of rheumatoid arthritis the histological changes do not necessarily run parallel with the clinical activity of the disease.

Topics: Arthritis, Rheumatoid; Biopsy, Needle; Edema; Endothelium; Female; Fibrin; Humans; Hyalin; Lymphocytes; Male; Muscle, Smooth, Vascular; Plasma Cells; Synovial Membrane; Vasculitis

The presence of immunoglobulin and complement deposits in cutaneous blood vessels and at the dermal junction was determined in 34 patients with rheumatoid arthritis (RA). Deposits of IgM and C3 were twice as common in the leg than the arm. The deposits were present in 7/14 patients with extraarticular disease and 1/20 patients with articular disease alone. Deposits of IgM were detected at the dermoepidermal junction in 4 patients with RA. All had circulating antinuclear antibodies.

Topics: Adult; Aged; Antibodies, Antinuclear; Arm; Arthritis, Rheumatoid; Blood Vessels; Complement C3; Female; Fibrin; Fluorescent Antibody Technique; Histocytochemistry; Humans; Immunoglobulin M; Leg; Lupus Erythematosus, Systemic; Male; Middle Aged; Osteoarthritis; Rheumatoid Factor; Skin

Topics: Antigen-Antibody Complex; Arthritis, Rheumatoid; Fibrin; Humans; Synovectomy; Synovial Membrane

Normal synovial membranes and synovial membranes from patients with classic rheumatoid arthritis were investigated for the presence of fibrin and fibronectin by an indirect immunoperoxidase technique. In normal synovial membranes, fibronectin was found around the monolayer of the synovial lining cells. Staining was most intense on the surface and beneath the lining cells, but not detectable in the cytoplasm. Fibronectin was also found in the cytoplasm of the endothelial cells. No staining for fibrin was found in the normal synovial membrane. In synovial membranes from patients with rheumatoid arthritis, large amounts of fibronectin were found around the multilayer of synovial lining cells, in the cytoplasm of the endothelial cells, and in argyrophilic fiber-rich connective tissue. In superficial areas denuded of synovial lining cells, high amounts of fibronectin were found incorporated in fibrin. In some areas with noninjured synovial lining cells, fibrin was also found, but in this case no fibronectin was incorporated. No fibronectin was found in connective tissue in areas with infiltration of inflammatory cells. After treatment of normal and rheumatoid synovial membranes with hyaluronidase, fibronectin was still present around the lining cells but the staining was found to be more distinct. This study relates the presence of fibrin and fibronectin in the rheumatoid synovial membrane to the high amount of these proteins, recently described, in rheumatoid synovial fluid. It also suggests that fibronectin present in the synovial membrane is produced and secreted by the endothelial cells.

Topics: Arthritis, Rheumatoid; Female; Fibrin; Fibronectins; Humans; Immunoelectrophoresis, Two-Dimensional; Immunoenzyme Techniques; Male; Synovial Fluid; Synovial Membrane

The renal biopsies of 30 patients with rheumatoid arthritis and clinical evidence of renal disease were reviewed; only patients in whom the intravenous pyelogram was normal were subjected to biopsy, thus excluding those with papillary necrosis and chronic pyelonephritis. Tissue was studied by light, electron and immunofluorescence microscopy. There were 13 cases of mesangial change, 9 of membranous glomerulonephritis, 4 of tubulointerstitial change, 2 cases of focal segmental glomerulosclerosis, 1 case of amyloid and 1 of diffuse proliferative glomerulonephritis with crescents. All 9 patients with membranous glomerulonephritis but only 6 of 13 with mesangial change had received gold or penicillamine. We found no evidence of "glomerulitis" or of a rheumatoid vasculitis.

Topics: Adult; Aged; Arthritis, Rheumatoid; Biopsy; Complement C3; Female; Fibrin; Glomerulonephritis; Gold; Humans; Immunoglobulins; Kidney; Male; Microscopy, Electron; Middle Aged; Penicillamine

In the early stage of rheumatoid synovitis, changes in synoviocytes of the cover layer in the joints with clinical manifestations of arthritis differ from stereotype reactions of these cells in the advanced stage of the disease. Fibrin, IgG and C3-fraction of complement are found on the surface and in the depth of the cover layer. Light and electron microscopy revealed the features of type B synoviocytes prevalent in the cover layer in the early stage of the disease: polymorphism and rounding of the nuclei of synoviocytes, mitoses, fragmentation and degeneration of the nucleolus, loosening of the chromatin network and appearance of interchromatin granules, nuclear bodies, formation of multinucleated synoviocytes and symplasts, destruction of organelles, activation of lysosomal apparatus of the cells. These changes may be interpreted as simultaneous manifestations of cell activation and cytopathologic effect. They are likely to be due to the effect of the etiological factor and immunocomplex mechanism. The detection of dystrophically altered chrondrocytes in the cover layer confirms the opinion of simultaneous participation of the synovial and cartilage components of the joint in the rheumatoid process.

Topics: Adult; Arthritis, Rheumatoid; Biopsy, Needle; Complement C3; Female; Fibrin; Humans; Immunochemistry; Immunoglobulin G; Male; Microscopy, Electron; Middle Aged; Synovial Membrane; Synovitis; Time Factors

Neuropathologic examination of an autopsy series of 54 patients of various types of CVD revealed a very high frequency of pathologic changes both in brain parenchyma (in 81%) and vessels (in 78%). A broad but continuous spectrum of primary vascular alterations was observed, ranging from fibrinoid deposits in intact or necrotizing vessel walls to fibrohyalinosis and endothelial proliferations. In acute SLE showing LE cells within brain tissues, immune complex deposits were observed for the first time in brain vessels, in addition to similar deposits in the plexus chorioideus and in hematoxylin bodies. Secondary complications are frequently affecting the brain in CVD; they are mainly sequels of systemic atherosclerosis, hypertension, thromboemboli from SLE endocarditis, cardiac, hepatic or renal dysfunctions, or infections and should be clinically differentiated from primary brain involvement in CVD to ensure the appropriate therapeutic measures.

Topics: Arthritis, Rheumatoid; Brain; Cerebral Arteries; Collagen Diseases; Complement C3; Fibrin; Humans; Immunoglobulin G; Lupus Erythematosus, Systemic; Myositis; Polyarteritis Nodosa; Purpura, Thrombotic Thrombocytopenic; Vascular Diseases; Vasculitis

Twenty patients with rheumatoid arthritis (RA) had a biopsy taken from clinically normal skin. These were examined for histological and immunological abnormalities and were compared to those of 8 patients with osteoarthritis (OA). No 'lupus band; linear deposition of immunoglobulin or complement at the dermo-epidermal interface was seen in any patient in either group. Perivascular deposits were seen in 5 out of 20 (25%) patients with RA. These were IgM in all 5 cases with additional C3 in 2 cases (10%) and additional fibrin in one case (5%). No immunoprotein deposits were seen in specimens from any OA patient. 4 of the 5 patients with perivascular immunoprotein deposits had circulating ANAs present and dilutions of 1/256 or higher but normal DNA binding. A sparse perivascular, predominantly lymphocytic infiltrate was seen in 13 out of 20 (65%) patients with RA and 3 of 8 (35%) patients with OA.

Topics: Arthritis, Rheumatoid; Fibrin; Fluorescent Antibody Technique; Humans; Immunoglobulin M; Osteoarthritis; Skin

A study of the use of immunofluorescence of synovial membranes in one hundred cases of various arthropathies reveals the value of the cytoplasmic localization of immune deposits and their type (Ig) in orienting the diagnosis, the influence of therapy, the lack of correlation with optical anatomopathology of synovial tissue (performed on another tissue fragment). Certain recurrent images such as fluorescence of blood vessel walls or the presence of fibrin are of little interest; other such as the cytoplasmic fluorescence of infiltrating cells and particularly, IgG-IgM mixed cellular fluorescence or coupled fluorescence-cellular with Ig and interstitial granular with Ig and C3 orientate the diagnosis to RA. Immunofluorescence appears to be of interest for inflammatory monoarthritis and probable RA. It is less interesting when the etiological context is limited. In addition, a negative immunofluorescent study does not rule out any diagnosis.

Topics: Arthritis, Rheumatoid; Complement C3; Fibrin; Fluorescent Antibody Technique; Humans; Immunoglobulin A; Immunoglobulin E; Immunoglobulin G; Immunoglobulin M; Joint Diseases; Synovial Membrane

Rheumatoid joint swelling is in part due to lymphoedema accompanying extravascular (E-V) deposition of fibrin. Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin (ASA), phenylbutazone (PBZ) and indomethacin (INDO) which share the ability to inhibit prostaglandin synthetase fail to prevent fibrinous lymphoedema occurring in rabbit skin homografts in association with the presence of sensitised lymphocytes. The data highlight the need to define whether or not prostaglandins promote lymphocytic fibrinous lymphoedema.

Topics: Animals; Anti-Inflammatory Agents; Arthritis, Rheumatoid; Cyclooxygenase Inhibitors; Fibrin; Indomethacin; Lymphedema; Lymphocytes; Prostaglandins; Rabbits; Skin Transplantation; Transplantation, Homologous

Psoriatic arthritis (PA) is included in the seronegative arthritis group, though it is now generally considered to represent a clinical entity. In PA, in contrast to psoriasis vulgaris and to other types of rheumatoid arthritis, only a few immunological studies have been reported. In the present report synovial joint membranes from patients with PA and control groups have been studied for the presence of (a) vascular changes, (b) fibrin, (c) immunoglobulins and complement factor C3.

Topics: Arthritis; Arthritis, Rheumatoid; Complement C3; Fibrin; Fluorescent Antibody Technique; Humans; Immunoglobulins; Psoriasis; Synovial Membrane; Vasculitis

Topics: Arthritis, Rheumatoid; Capillaries; Connective Tissue; Fibrin; Humans; Synovial Membrane

Desmosomes or desmosome-like structures do not occur between normal synovial cells but such structures do develop between the synovial cells in cases of traumatic arthritis, rheumatoid arthritis and villonodular synovitis. Morphological evidence is presented suggesting that such structures develop as a result of the interaction of fibrin trapped between synovial cells and the plasmamembrane of these cells.

Topics: Arthritis, Rheumatoid; Desmosomes; Fibrin; Humans; Synovial Membrane; Synovitis

Plasminogen-free fibrin plate (fP) which was made from treated commerical bovine fibrinogen with Lysine-Sepharose was developed in our laboratory. This new fibrin plate showed the following specificities. a) This new fibrin plate did not show any lysis with high amount of streptokinase and Urokinase (10,000 u/ml and 500 u/ml). b) The concentrations of its substrate was the same as standard plate (SP) and its substrate was not denatured compared with heated plate (HP). c) The activity of plasmin can be measured quantitatively on fP and linear correlation between plasmin units and lysis area was showen. d) This procedure of new fibrin plate was easy and simple and could be applicable to the materials of other species, i.e., human, rabbit and porcine. With the use of two kinds of bovine fibrin plate (SP and fP), activation of fibrinolysis of human plasma, euglobulin and plasminogen induced by SK and UK was investigated and each correlation ship between sample and activator was studied statistically. From these results, "Index of fibrinolysis" meaning of fibrinolytic components such as plasmin, plasminogen, activator, proactivator, anti-activator and anti-plasmin were indicated. Indeed, these index of fibrinolysis were calculated from the lysis area of plasma+SK, Eug.+SK and Eug.+UK by each formula and index obtained from some physiological and pathological condition showed us many new information about fibrinolysis.

Topics: Animals; Arthritis, Rheumatoid; Collagen Diseases; Fibrin; Fibrinogen; Fibrinolysin; Fibrinolysis; Hot Temperature; Humans; Methods; Physical Exertion; Plasminogen; Plasminogen Activators; Serum Globulins; Solubility; Streptokinase; Urokinase-Type Plasminogen Activator

Six rheumatoid articular cartilage specimens, which appeared grossly normal and were shown to be free of pannus when examined under the light microscope, were examined electron microscopically. For comparison, normal-appearing cartilage specimens from 2 patients with meniscus injury and 2 with degenerative joint disease (DJD) were also examined. In all cases the normal-appearing joint surface of rheumatoid cartilage was abnormal. Amorphous-appearing material was present to a depth varying between 6 and 25 micron. Some of this material had the appearance of fibrin deposited at the cartilage surface, but much appeared to represent breakdown products of the cartilage matrix, i.e. degraded collagen and proteoglycan. DJD cartilage did not show similar changes. The findings suggest that the surface of rheumatoid articular cartilage, even when grossly normal in appearance, is degraded by enzymes either present in the synovial fluid or released by polymorphonuclear cells in close contact with the cartilage surface.

Topics: Adult; Arthritis, Rheumatoid; Cartilage, Articular; Collagen; Female; Fibrin; Humans; Male; Middle Aged; Synovial Fluid

Rheumatoid arthritis (RA) was differentiated from systemic lupus erythematosus (SLE) by direct immunofluorescent techniques on skin specimens, using monospecific antisera for IgG, IgM, C3, C1q, properdin, and fibrin. Of 30 patients with RA studied, 20 had dermal vessel deposits of immunoglobulins and complement components in unaffected skin without the characteristic dermal-epidermal junctional fluorescence of SLE. Of 24 SLE patients studied, 24 had granular deposits of immunoglobulins and complement components in unaffected skin at the dermal-epidermal junction.

Topics: Arthritis, Rheumatoid; Complement C1; Complement C3; Complement System Proteins; Fibrin; Humans; Immunoglobulin G; Immunoglobulin M; Immunoglobulins; Lupus Erythematosus, Systemic; Middle Aged; Properdin; Skin

Topics: Acid Phosphatase; Arthritis, Rheumatoid; Cell Count; Fibrin; Humans; Proteoglycans; Synovial Fluid; Synovial Membrane; Synovitis

Topics: Adult; Arthritis, Rheumatoid; Blood Coagulation; Fibrin; Humans; Middle Aged; Penicillamine

Fibrin/fibrinogen degradation products observed in rheumatoid synovial fluid exhibit resistance to plasmin proteolysis. In the present study, the influence of the common bile acids on the plasmin digestion of these degradation products in 16 rheumatoid synovial fluids were quantitated immunologically by radial immunodiffusion, and qualitatively estimated by crossed immunoelectrophoresis. Addition of chenodeoxycholic acid, deoxycholic acid, and their taurine and glycine conjugates in concentrations of 3.33 mumole/ml of a mixture of rheumatoid synovial fluid and plasmin resulted in complete plasmin degradation. Cholic acid and its taurine and glycine conjugates were effective only in concentrations of 4.44 mumole/ml. A detergent, such as Triton X-100, had little or no effect on the plasmin digestion. Other proteins capable of influencing fibrinolytic activity, such as plasminogen and the inhibitors alpha1-antitrypsin and alpha2-macroglobulin, were not affected by the two detergents. The bile acids are thought to influence the fibrin/fibrinogen degradation products by unfolding the protein at a molecular level, by virtue of their properties as steroid detergents, leaving the fibrin/fibrinogen degradation products susceptible to plasmin digestion.

Topics: alpha 1-Antitrypsin; Alpha-Globulins; Arthritis, Rheumatoid; Bile Acids and Salts; Fibrin; Fibrinogen; Fibrinolysin; Humans; Macroglobulins; Plasminogen; Stimulation, Chemical; Synovial Fluid

Because rheumatoid inflammation is associated with the presence of large numbers of leukocytes in joint effusions, the question of whether enzymatic splitting of collagen and fibrin can lead to generation of chemotactic factors was investigated. Fibrinogen was purified from the plasma of four different species, and the homogeneity of the preparations was established by physicochemical and immunologic techniques. Fibrin was prepared and then lysed with plasmin to obtain fibrin degradation products (FDP). Similarly, purified collagenase was used to lyse collagen in vitro, and the chemotactic activity of the reaction mixtures was analyzed. The experiments presented indicate that fibrinogen, fibrin, and plasmin do not possess any intrinsic chemotactic activity. However, when fibrin was split by plasmin, FDP of human, bovine, sheep, and equine origin all proved to be strong leukotactic agents for polymorphonuclear leukocytes (PMN). Purified collagenase per se was found to be a cell type-specific chemotactic agent for PMN. Not only were collagen degradation products not chemotactic, but they also inhibited the leukotactic activity of the purified collagenase. Furthermore, this inhibition of the chemotactic activity of collagenase was independent of its enzymatic activity. The results presented suggest that there is a direct correlation between the process of fibrinolysis and the chemotactic attraction of leukocytes and between the presence of collagenase and leukotaxis. This system may serve as a model to explain the mechanisms by which cells accumulate in inflamed joints.

Topics: Animals; Arthritis, Rheumatoid; Cattle; Cells, Cultured; Chemotaxis; Collagen; Fibrin; Fibrinogen; Fibrinolysin; Fibrinolysis; Horses; Humans; Macrophages; Male; Microbial Collagenase; Neutrophils; Rats; Sheep; Thrombin

Topics: Amyloid; Arthritis, Rheumatoid; Basement Membrane; Biopsy; Blood Proteins; Complement System Proteins; Diagnosis, Differential; Fibrin; Glomerulonephritis; Glycoproteins; Granulomatosis with Polyangiitis; Histocytochemistry; Humans; Hypersensitivity; Immunoglobulins; Kidney Glomerulus; Methenamine; Methods; Proteins; Purpura; Silver; Staining and Labeling

Topics: Aged; Arthritis, Rheumatoid; Blood Cell Count; Blood Platelets; Carbon Radioisotopes; Collagen Diseases; Factor XIII; Female; Fibrin; Fibrinolysis; Heart Failure; Humans; Hypertension, Malignant; Infections; Leukemia; Liver Diseases; Neoplasms; Pulmonary Embolism; Sepsis; Streptokinase

Topics: Animals; Arthritis, Rheumatoid; Colloids; Disease Models, Animal; Female; Fibrin; Forelimb; Freund's Adjuvant; Hindlimb; Joints; Lymphocytes; Macrophages; Male; Radiation Effects; Radioisotopes; Rats; Synovial Membrane; Yttrium Isotopes

Topics: alpha 1-Antitrypsin; Animals; Antigens; Arthritis, Rheumatoid; Fibrin; Fibrinogen; Fibrinolysin; Humans; Immune Sera; Immunodiffusion; Immunoelectrophoresis; Injections, Intra-Articular; Macroglobulins; Molecular Weight; Peptide Biosynthesis; Peptide Hydrolases; Rabbits; Rh-Hr Blood-Group System; Synovial Fluid

Topics: Activation Analysis; Arthritis, Rheumatoid; Aurothioglucose; Fibrin; Gold; Gold Sodium Thiomalate; Humans; Methods; Plasma; Spectrophotometry, Atomic; Time Factors; Viscosity; Water

Topics: Adolescent; Adult; Arthritis; Arthritis, Rheumatoid; Biopsy; Child; Diagnosis, Differential; Female; Fibrin; Follow-Up Studies; Histocytochemistry; Humans; Knee; Knee Joint; Male; Middle Aged; Prognosis; Retrospective Studies; Rheumatoid Factor; Synovial Membrane; Synovitis

Topics: Arthritis, Rheumatoid; Autopsy; Collagen Diseases; Dermatomyositis; Diagnosis, Differential; Fibrin; Granuloma; Histocytochemistry; Humans; Lung; Lupus Erythematosus, Systemic; Polyarteritis Nodosa; Pulmonary Alveoli; Pulmonary Fibrosis; Rheumatic Fever; Scleroderma, Systemic

Topics: Adult; Aged; Albumins; Arthritis; Arthritis, Rheumatoid; Complement System Proteins; Female; Fibrin; Fibrinogen; Fibrinolysin; Fluorescent Antibody Technique; Humans; Immune Sera; Immunoglobulins; Male; Middle Aged; Osteoarthritis; Synovial Membrane

Topics: Arthritis, Rheumatoid; Blood Sedimentation; Exudates and Transudates; Fibrin; Gangrene; Humans; Osteoarthritis; Polyarteritis Nodosa; Synovial Fluid; Vascular Diseases; Wounds and Injuries

Topics: Arthritis, Rheumatoid; Blood Donors; Fibrin; Fibrinogen; Humans

Topics: Adolescent; Adult; Aged; Arthritis, Rheumatoid; Biopsy; Collagen; Cytoplasm; Endoplasmic Reticulum; Female; Fibrin; Humans; Knee; Lysosomes; Male; Menisci, Tibial; Middle Aged; Synovectomy; Synovial Membrane; Time Factors

Topics: Arthritis, Rheumatoid; Cell Differentiation; Connective Tissue; Fibrin; Fibroblasts; Humans; Necrosis; Synovial Membrane

Topics: Adrenal Cortex Hormones; Arthritis, Rheumatoid; Cartilage; Collagen Diseases; Connective Tissue; Dermatomyositis; Fibrin; Giant Cell Arteritis; Humans; Lupus Erythematosus, Systemic; Rheumatic Fever; Scleroderma, Systemic

Topics: Animals; Ankylosis; Arthritis, Rheumatoid; Fibrin; Fibrinolysin; Fibrinolysis; Humans; Plasminogen; Thrombelastography

Topics: Arthritis, Rheumatoid; Collagen; Connective Tissue; Endoplasmic Reticulum; Fibrin; Golgi Apparatus; Humans; Microscopy, Electron; Synovial Fluid; Synovial Membrane

Topics: Adolescent; Adult; Aged; Arthritis, Rheumatoid; Blood Proteins; Evaluation Studies as Topic; Female; Fibrin; Fibrinogen; Humans; Male; Methods; Middle Aged

Topics: Arthritis, Rheumatoid; Chronic Disease; Fibrin; Humans; Inflammation; Microscopy, Electron; Necrosis; Synovial Membrane; Synovitis

Topics: Animals; Arthritis, Rheumatoid; Blood Coagulation Tests; Cats; Cattle; Chromatography, Gel; Electrophoresis; Fibrin; Fibrinogen; Fibrinolysin; Fibrinolysis; Humans; Liver Cirrhosis; Methods; Prothrombin Time; Rabbits; Staphylococcus; Streptokinase; Thrombin; Thrombosis; Time Factors

Topics: Adult; Agglutination Tests; Arthritis, Rheumatoid; Blood Coagulation; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Contraceptives, Oral; Erythrocytes; False Negative Reactions; False Positive Reactions; Female; Fibrin; Fibrinogen; Fibrinolysin; Fibrinolysis; Hemagglutination Inhibition Tests; Hodgkin Disease; Humans; Immunoassay; Immunodiffusion; Kidney Diseases; Liver Cirrhosis; Lymphoma, Non-Hodgkin; Male; Methods; Middle Aged; Myocardial Infarction; Neoplasms; Plasminogen; Staphylococcus

Topics: Antibody Formation; Arthritis, Rheumatoid; Fibrin; Hexoses; Humans; Neuraminic Acids; Rheumatoid Factor

Topics: Adolescent; Adult; Age Factors; Aged; Animals; Anticoagulants; Arthritis, Rheumatoid; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Cardiovascular Diseases; Cattle; Child; Child, Preschool; Dogs; Electrophoresis; Female; Fibrin; Fibrinolysin; Fibrinolysis; Fibrinolytic Agents; Hemorrhage; Hemorrhagic Disorders; Humans; Infant; Male; Menstruation; Methods; Middle Aged; Neoplasms; Plasminogen; Pregnancy; Rabbits; Sex Factors; Thromboembolism; Thrombosis; Uremia

Topics: Arthritis, Rheumatoid; Female; Fibrin; Histocytochemistry; Humans; Male; Necrosis; Placenta; Rheumatoid Nodule; Stomach Ulcer; Synovial Membrane

Topics: Arteries; Arthritis, Rheumatoid; Chronic Disease; Fibrin; Fibroblasts; Humans; Inflammation; Myocardium; Necrosis; Pericardium; Serous Membrane; Spleen; Tendons

Topics: Adult; Animals; Antifibrinolytic Agents; Arthritis, Rheumatoid; Blood Sedimentation; Coronary Disease; Erythrocytes; Fibrin; Fibrinogen; Humans; Middle Aged; Multiple Sclerosis; Neurotic Disorders; Protamines; Rabbits; Rats; Staphylococcal Infections

Topics: Adjuvants, Immunologic; Animals; Antibodies; Antigens; Arthritis, Rheumatoid; Autoimmune Diseases; Chronic Disease; Fibrin; Gout; Humans; Hypersensitivity, Delayed; Inflammation; Joints; Macrophages; Mycobacterium tuberculosis; Plasma Cells; Polysaccharides; Rabbits; Synovitis; Uric Acid

Topics: Analysis of Variance; Arthritis, Rheumatoid; Blood Coagulation; Blood Proteins; Female; Fibrin; Fibrinogen; Fibrinolysis; Heparin Antagonists; Humans; Male; Mathematics; Middle Aged; Mononuclear Phagocyte System; Thrombosis

Topics: Animals; Arthritis, Rheumatoid; Fibrin; Freund's Adjuvant; Haplorhini; Injections, Intradermal; Injections, Intramuscular; Injections, Subcutaneous

Topics: Adult; Aged; Arthritis, Rheumatoid; Fibrin; Humans; Middle Aged; Rheumatoid Factor; Synovial Fluid

Topics: Animals; Antigens; Arthritis; Arthritis, Experimental; Arthritis, Rheumatoid; Autoimmune Diseases; Fibrin; Hypersensitivity, Delayed; Injections, Intra-Articular; Pathology; Rabbits; Research

Topics: Arthritis, Rheumatoid; Fibrin; Fibrinogen; Fluorescent Antibody Technique; Humans; In Vitro Techniques; Leukocytes; Microscopy, Electron; Neutrophils; Phagocytosis; Rheumatoid Factor; Synovial Fluid

Topics: Arthritis, Rheumatoid; Chemistry Techniques, Analytical; Fibrin; Humans; Joint Diseases; Microscopy, Electron; Mucoproteins; Synovial Fluid

Topics: Allergy and Immunology; Antibodies; Arthritis; Arthritis, Rheumatoid; Collagen; Fibrin; gamma-Globulins; Humans; Rheumatoid Factor

Topics: Allergy and Immunology; Animals; Antigen-Antibody Reactions; Arthritis; Arthritis, Rheumatoid; Fibrin; Haplorhini; Humans; Pathology; Rheumatic Diseases; Rheumatoid Factor; Rheumatoid Nodule

Topics: Arthritis; Arthritis, Rheumatoid; Blood Sedimentation; Fibrin; Humans; Rheumatic Heart Disease; Tonsillitis

Topics: Aniline Compounds; Arthritis; Arthritis, Rheumatoid; Blood Sedimentation; Diagnosis; Diphenylamine; Fibrin; Leukocytosis; Leukopenia; Rheumatic Diseases; Tonsillitis

Topics: Arthritis; Arthritis, Rheumatoid; Fibrin; Humans; Rheumatic Diseases

Topics: Arthritis; Arthritis, Rheumatoid; Fibrin; Humans

Topics: Adrenocorticotropic Hormone; Arthritis; Arthritis, Rheumatoid; Fibrin; Fibrinogen; Protamines