thromboplastin and Lupus-Erythematosus--Systemic

Systemic lupus erythematosus (SLE) is a potentially fatal multiorgan inflammatory disease that primarily affects females. Due to the heterogeneity of clinical manifestations and lack of laboratory tests that are both specific and sensitive for the disease, diagnosis of SLE can often be difficult. Although the precise etiology remains to be fully elucidated, it is probable that various environmental, genetic, and hormonal factors contribute to the development of the disease. Patients with SLE have an increased risk for premature thrombosis and/or atherosclerosis, with up to half experiencing a thrombotic event. Furthermore, antiphospholipid antibodies probably play a key role in the development of thrombosis by affecting various hemostatic protein interactions with phospholipids and cell surfaces as well as platelet function. Despite recent advances in knowledge related to the factors that contribute to the pathophysiology of SLE, numerous challenges related to earlier diagnosis as well as the prediction and prevention of thrombotic events remain to be fully addressed.

Topics: Antibodies, Antinuclear; Antibodies, Antiphospholipid; Atherosclerosis; Blood Platelets; Female; Humans; Lupus Erythematosus, Systemic; Protein C; Risk Factors; Thromboplastin; Thrombosis

Sera from patients with systemic lupus erythematosus have been reported to contain IgM and/or IgG binding to endothelial cells (EC), i.e. anti-EC antibodies (AECA). Similar autoantibodies have been claimed to occur in a number of conditions associated with vasculitis. The original cyto-enzyme-linked immunosorbent assay (ELISA) remains the most widely used method for the detection of AECAs, although numerous pitfalls have been identified since then. These difficulties may explain why a consensus on the prevalence of AECAs has not been reached thus far. It is therefore desirable to confirm a positive result in the cyto-ELISA using other methods, such as flow cytometry, immunoprecipitation or Western blot. Yet, these methods appear to be difficult to use on a routine basis. With regard to the AECA effects, their binding induces activation of ECs, as substantiated by up-regulation of adhesion molecules, and synthesis of cytokines and chemokines, followed by their secretion. Some of these autoantibodies encourage the local production of tissue factor, and thereby favour coagulation. Other AECAs trigger apoptosis of ECs, although the Fas receptor does not seem to be involved in this process. In fact, since the target antigens are not well defined, the current challenge is to identify EC target molecules, and thus to gain further insights into the pathogenesis of diseases with vasculitis.

Topics: Autoantibodies; Autoantigens; beta 2-Glycoprotein I; Blotting, Western; Cytotoxicity, Immunologic; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Glycoproteins; Heparitin Sulfate; Humans; Lupus Erythematosus, Systemic; Membrane Proteins; Models, Immunological; Thromboplastin

Topics: Amino Acid Sequence; Antibodies, Catalytic; Autoantibodies; Binding Sites; Humans; Immunoglobulin Light Chains; In Vitro Techniques; Lupus Erythematosus, Systemic; Molecular Sequence Data; Prothrombin; Thromboplastin

Antiphospholipid-protein antibodies (APA) are a family of immunoglobulins which have been defined by varying laboratory test systems. Lupus anticoagulants (LA) and anticardiolipin antibodies (ACA) are the two most prominent members of this family of antibodies. LA are detected utilizing various phospholipid (PL) dependent tests of coagulation (e.g., activated partial thromboplastin time [APTT], Kaolin Clotting Time [KCT], dilute Russell Viper Venom Time [dRVVT]). Originally, LA were thought to be a laboratory nuisance since the vast majority of individuals with LA did not bleed. Paradoxically, patients with LA were found to have an increased incidence of thromboembolic events and also recurrent spontaneous abortions (RSA). Thus, the laboratory detection of LA has become part of the work up of patients with thromboembolic disorders and RSA. ACA are detected using solid phase assay systems (radioimmunoassay or ELISA). The presence of ACA has the same clinical implications as that of LA. Although originally it was suggested ACA and LA were the same antibody, it is now well accepted that they, in many instances, are different antibodies. Therefore, it is critical for laboratories to evaluate patient samples for both LA and ACA. In approximately 60% of circumstances, both antibodies will be found. In the remaining cases, there will be discordance between the two test systems. The question of whether APA are causative, coincidental, or a consequence of the clinical complications of RSA and thrombosis remains controversial. Recent evidence based on prospective clinical studies and analysis of markers of in vivo coagulation suggests APA are causative.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Abortion, Habitual; Adult; Animals; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; Autoimmune Diseases; beta 2-Glycoprotein I; Cattle; Eicosanoids; Endothelium, Vascular; Female; Glycoproteins; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Pregnancy; Thromboplastin; Thrombosis

Topics: Anticoagulants; Blood Coagulation Tests; Enzyme-Linked Immunosorbent Assay; Heparin; Humans; Immunoglobulin G; Immunoglobulins; Lupus Erythematosus, Systemic; Phospholipids; Thromboplastin; Thrombosis

Topics: Autoantibodies; Autoimmune Diseases; Blood Coagulation Factors; Blood Coagulation Tests; Collagen Diseases; Drug Hypersensitivity; False Positive Reactions; Female; Hemorrhage; Humans; Immunoglobulin M; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Neoplasms; Pregnancy; Pregnancy Complications, Hematologic; Thromboplastin; Thrombosis

Topics: Adult; Antibodies; Anticoagulants; Antifibrinolytic Agents; Blood Coagulation Disorders; Blood Coagulation Tests; Blood Platelets; Blood Transfusion; Factor VIII; Female; Hemophilia A; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Prothrombin Time; Thrombin; Thromboplastin

To determine if proinflammatory and prothrombotic biomarkers are differentially upregulated in persistently antiphospholipid antibody (aPL)-positive patients, and to examine the effects of fluvastatin on these biomarkers.. Four groups of patients (age 18-65) were recruited: (a) primary antiphospholipid syndrome; (b) systemic lupus erythematosus (SLE) with antiphospholipid syndrome (APS) (SLE/APS); (c) persistent aPL positivity without SLE or APS (Primary aPL); and (d) persistent aPL positivity with SLE but no APS (SLE/aPL). The frequency-matched control group, used for baseline data comparison, was identified from a databank of healthy persons. Patients received fluvastatin 40 mg daily for 3 months. At 3 months, patients stopped the study medication and they were followed for another 3 months. Blood samples for 12 proinflammatory and prothrombotic biomarkers were collected monthly for 6 months.. Based on the comparison of the baseline samples of 41 aPL-positive patients with 30 healthy controls, 9/12 (75%) biomarkers (interleukin (IL)-6, IL1β, vascular endothelial growth factor (VEGF), tumour necrosis factor (TNF)-α, interferon (IFN)-α, inducible protein-10 (IP10), soluble CD40 ligand (sCD40L), soluble tissue factor (sTF) and intracellular cellular adhesion molecule (ICAM)-1) were significantly elevated. Twenty-four patients completed the study; fluvastatin significantly and reversibly reduced the levels of 6/12 (50%) biomarkers (IL1β, VEGF, TNFα, IP10, sCD40L and sTF).. Our prospective mechanistic study demonstrates that proinflammatory and prothrombotic biomarkers, which are differentially upregulated in persistently aPL-positive patients, can be reversibly reduced by fluvastatin. Thus, statin-induced modulation of the aPL effects on target cells can be a valuable future approach in the management of aPL-positive patients.

Topics: Adult; Antiphospholipid Syndrome; Biomarkers; Cell Adhesion Molecules; Cytokines; Fatty Acids, Monounsaturated; Female; Fluvastatin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Indoles; Inflammation Mediators; Intercellular Adhesion Molecule-1; Lupus Erythematosus, Systemic; Male; Middle Aged; Pilot Projects; Prospective Studies; Thromboplastin; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1; Vascular Endothelial Growth Factor A

In a first study, we performed a cross-sectional analysis of urinary excretion of isoprostanes, IPF(2alpha-III) and (VI), and monocyte tissue factor (TF) antigen and activity between 11 antiphospholipid (APL) antibody-positive patients and 13 APL negative subjects. In a second study, 11 APL positive patients were randomly supplemented either with (n = 6) or without (n = 5) antioxidants (vitamin E at 900 IU day(-1), vitamin C at 2000 mg day(-1)) for 6 weeks. In a third study, TF and superoxide anion were measured in human monocytes incubated with anti-beta(2) glycoprotein 1 (beta(2)GP(1)) or control IgG, either with or without vitamin E. APL-positive patients had higher values of isoprostanes (P < 0.05) and monocyte TF antigen (P = 0.001) and activity (P = 0.0001) than APL-negative subjects. Only in APL positive patients did monocyte TF antigen correlate significantly with IPF(2alpha-III) (rho 0.79; P < 0.003) and IPF(2alpha-VI) (rho = 0.87; P < 0.0001). In patients who received antioxidant supplementation, we found a significant decrease of isoprostanes (P < 0.05) and monocyte TF antigen (P < 0.01) and activity (P < 0.007). In vitro experiments demonstrated that anti-beta(2)GP(1) antibodies dose-dependently enhanced the monocyte production of the superoxide anion and TF, which were significantly inhibited by vitamin E. This study demonstrates that in APL-positive patients, oxidative stress contributes to activate the clotting system via over-expression of monocyte TF. We suggest that anti-beta(2)GP(1) antibodies could play a pivotal role by enhancing the monocyte production of oxygen free radicals.

Topics: Adult; Antibodies, Antiphospholipid; Antioxidants; Antiphospholipid Syndrome; Cross-Sectional Studies; Dose-Response Relationship, Drug; Female; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Monocytes; Oxidative Stress; Superoxides; Thromboplastin

In a controlled, prospective study of 44 consecutive women with idiopathic habitual abortion, only 5% had symptoms of rheumatic disease. Patients did not differ from control subjects in the frequency of positive results on tests for antinuclear antibody or anti-double-stranded DNA. Levels of C3 and C4 were higher in the habitual aborters. No patients had anti-Ro. The antiphospholipid antibody results were analyzed using 2 methods: the frequency of antiphospholipid antibodies was 9% by lupus anticoagulant using the Russell viper venom time (95% confidence interval 22-2.5) and 11% by anticardiolipin antibody assay (95% confidence interval 25-3.7), which was not significantly different from that in control subjects. However, the mean levels in the aborters (although within the normal range) were significantly higher than those in control subjects for anti-double-stranded DNA (P = 0.004), lupus anticoagulant (by Russell viper venom time; P = 0.05), and anticardiolipin antibody (P = 0.0007), when examined by multiple linear regression analysis corrected for age and concurrent pregnancy. Of the 3 patients with antiphospholipid antibodies and subsequent successful pregnancies, only 1 was treated with prednisone and aspirin. We conclude that, in the majority of women, subclinical lupus, anti-Ro, the lupus anticoagulant, and anticardiolipin antibodies are not associated with idiopathic habitual abortion.

Topics: Abortion, Habitual; Adult; Antibodies, Antinuclear; Autoantibodies; Blood Coagulation Factors; Cardiolipins; Clinical Trials as Topic; Female; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Pregnancy; Prospective Studies; Thromboplastin

Antibodies specific for cardiolipin (CL)-β

Topics: Animals; Antibodies, Antinuclear; Antiphospholipid Syndrome; beta 2-Glycoprotein I; DNA; Gene Expression; Humans; Lupus Erythematosus, Systemic; Mice; Monocytes; Signal Transduction; Thromboplastin; Toll-Like Receptor 9

We have explored the relationship between possible hemostatic changes and clinical manifestation of the systemic lupus erythematosus (SLE) as a function of greater or lesser disease activity according to Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2K) criteria. Endothelial injury and hypercoagulability were investigated in patients with SLE by measuring thrombomodulin (TM), D-dimer (DDi) and thrombin generation (TG) potential. A total of 90 participants were distributed into three groups: 1) women with SLE presenting with low disease activity (laSLE) (SLEDAI-2K ≤ 4), 2) women with SLE presenting with moderate to high disease activity (mhaSLE) (SLEDAI-2K > 4), and 3) a control group comprising healthy women. Levels of TM and DDi were higher both in the laSLE and mhaSLE groups compared to controls and in mhaSLE compared to the laSLE group. With respect to TG assay, lagtime and endogen thrombin potential, low concentrations of tissue factor provided the best results for discrimination among groups. Analysis of these data allow us to conclude that TM, DDi and TG are potentially useful markers for discriminating patients with very active from those with lower active disease. Higher SLE activity may cause endothelial injury, resulting in higher TG and consequently a hypercoagulability state underlying the picture of thrombosis common in this inflammatory disease.

Topics: Adult; Biomarkers; Case-Control Studies; Cross-Sectional Studies; Endothelium, Vascular; Female; Fibrin Fibrinogen Degradation Products; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Severity of Illness Index; Thrombomodulin; Thrombophilia; Thromboplastin; Young Adult

The release of neutrophil extracellular traps (NETs) represents a novel neutrophil effector function in systemic lupus erythematosus (SLE) pathogenesis. However, the molecular mechanism underlying NET release and how NETs mediate end-organ injury in SLE remain elusive.. NET formation and NET-related proteins were assessed in the peripheral blood and biopsies from discoid lupus and proliferative nephritis, using immunofluorescence, immunoblotting, quantitative PCR and ELISA. Autophagy was assessed by immunofluorescence and immunoblotting. The functional effects of NETs in vitro were assessed in a primary fibroblast culture.. Neutrophils from patients with active SLE exhibited increased basal autophagy levels leading to enhanced NET release, which was inhibited in vitro by hydroxychloroquine. NETosis in SLE neutrophils correlated with increased expression of the stress-response protein REDD1. Endothelin-1 (ET-1) and hypoxia-inducible factor-1α (HIF-1α) were key mediators of REDD1-driven NETs as demonstrated by their inhibition with bosentan and L-ascorbic acid, respectively. SLE NETs were decorated with tissue factor (TF) and interleukin-17A (IL-17A), which promoted thrombin generation and the fibrotic potential of cultured skin fibroblasts. Notably, TF-bearing and IL-17A-bearing NETs were abundant in discoid skin lesions and in the glomerular and tubulointerstitial compartment of proliferative nephritis biopsy specimens.. Our data suggest the involvement of REDD1/autophagy/NET axis in end-organ injury and fibrosis in SLE, a likely candidate for repositioning of existing drugs for SLE therapy. Autophagy-mediated release of TF-bearing and IL-17A-bearing NETs provides a link between thromboinflammation and fibrosis in SLE and may account for the salutary effects of hydroxychloroquine.

Topics: Autophagy; Cell Culture Techniques; Extracellular Traps; Fibroblasts; Fibrosis; Humans; Inflammation; Interleukin-17; Lupus Erythematosus, Systemic; Signal Transduction; Thromboplastin; Thrombosis; Transcription Factors

Systemic Lupus Erythematosus (SLE) and antiphospholipid syndrome (APS) are associated with a high prevalence of atherosclerosis. β2 glycoprotein I (β2GPI) represents a link between autoimmunity and endothelial dysfunction. Recently, β2GPI reactive T cells have been identified; however, their role in atherosclerosis is still under investigation. We evaluated early atherosclerosis in patients with SLE and APS and investigated T cell reactivity to β2GPI and its relationship with atherosclerotic process.. Fifty SLE, 18 patients with primary APS (PAPS), and 25 healthy controls were enrolled. Demographic and clinical data, including traditional cardiovascular risk factors, were recorded. Monocyte β2GPI and Tissue Factor (TF) expression and peripheral blood mononuclear cell response to β2GPI stimulation were evaluated. Doppler ultrasound was performed to investigate flow-mediated dilatation (FMD) and carotid intima-media thickness (IMT). We detected an increase in mean IMT and a decrease in FMD in patients with SLE versus controls (P<0.05 and P=0.0001, respectively) and a decrease in FMD in patients with PAPS versus controls (P<0.05). Monocyte β2GPI and TF expression was higher in patients with SLE and PAPS than in controls (P=0.006 and P=0.001, respectively); no correlation of monocyte β2GPI and TF with IMT or FMD was detected. β2GPI induced peripheral blood mononuclear cell proliferation in 32% of patients with SLE, 25% of patients with PAPS yet in none of the controls. Proliferative response to β2GPI correlated with a history of arterial thrombosis, thrombocytopenia, and IMT >0.9 mm.. A significant percentage of patients with SLE and PAPS show a β2GPI-specific T cell reactivity, which is associated with subclinical atherosclerosis.

Topics: Adult; Aged; Antibody Specificity; Antiphospholipid Syndrome; Atherosclerosis; Autoantibodies; Autoantigens; beta 2-Glycoprotein I; Blood Pressure; Cardiovascular Diseases; Carotid Intima-Media Thickness; Cell Division; Endothelium, Vascular; Female; Hemorheology; Humans; Interferon-gamma Release Tests; Lipoproteins, HDL; Lupus Erythematosus, Systemic; Male; Middle Aged; Monocytes; Risk Factors; T-Cell Antigen Receptor Specificity; Thromboplastin; Vasodilation; Young Adult

CD36, known as a scavenger receptor, is a transmembrane glycoprotein expressed on monocytes, platelets and endothelial cells, recognizes multiple ligands, including phosphatidylserine, and regulates atherogenesis and thrombosis. The objective of this study is to investigate the possible involvement of CD36 in the pathophysiology of thrombosis in patients with antiphospholipid syndrome (APS).. First, rs3765187, a missense mutation linked to CD36 deficiency, was investigated by TaqMan polymerase chain reaction (PCR) genotyping method in 819 Japanese, including 132 patients with APS, 265 with systemic lupus erythematosus (SLE) in the absence of APS, and 422 healthy subjects. Then, the involvement of CD36 in antiphospholipid antibody (aPL)-induced tissue factor (TF) expression was examined using CD36-null mice or anti-CD36. Purified IgG from patients with APS and a monoclonal phosphatidylserine-dependent antiprothrombin antibody were used in these experiments. TF expression was tested by real-time PCR and flow cytometry.. Minor allele carrier of rs3765187 was less frequent in patients with APS (3.8% p=0.032), but not in patients with SLE in the absence of APS (7.9% p=0.32), compared with healthy subjects (10.2%). The aPL-induced TF expression was significantly suppressed on peritoneal macrophages from CD36-null mice compared to wild type and significantly inhibited by anti-CD36 on human monocytes.. The gene mutation linked to CD36 deficiency was less frequent in patients with APS. The deficient or suppressed CD36 function significantly reduced aPL-induced TF expression in vitro. Taken together, in a susceptible background CD36 scavenger receptor function may be involved in the thrombotic pathophysiology in patients with APS.

Topics: Adolescent; Adult; Aged; Animals; Antibodies, Antiphospholipid; Antiphospholipid Syndrome; Case-Control Studies; CD36 Antigens; Female; Flow Cytometry; Genotype; Humans; Japan; Lupus Erythematosus, Systemic; Macrophages, Peritoneal; Male; Mice; Mice, Knockout; Middle Aged; Monocytes; Mutation, Missense; Polymerase Chain Reaction; Real-Time Polymerase Chain Reaction; Thromboplastin; Thrombosis; Young Adult

In systemic lupus erythematosus (SLE) patients, the prevalence of arteriosclerosis obliterans (ASO) is high despite a lack of common risk factors for ASO. The main objective of this study was to investigate a possible direct role of anti-phospholipid antibodies (aPLs), which are frequently detected in SLE patients, in the pathogenesis of ASO.. We examined tissue factor (TF) expression on the monocyte surface by flow cytometric analysis in 89 SLE patients with or without ASO and/or aPLs and studied the in vitro effect of purified IgG fractions from plasma of SLE patients or normal healthy volunteers (aPLs(+) IgG, n=8; aPLs(-) IgG, n=6; Normal IgG, n=6) on the expression of TF and production of TNF-α and IL-1β in healthy peripheral blood mononuclear cells (PBMCs) or isolated monocytes.. We confirmed that high expression of monocyte TF was strongly associated with the prevalence of ASO and the presence of aPLs. Treatments of PBMCs with aPLs(-) IgG or normal IgG did not significantly increase expression of TF, TNF-α, and IL-1β messenger RNA (mRNA) and the production of TNF-α and IL-1β. However, stimulation of PBMCs with aPLs(+) IgG caused significant increase in expression of TF, TNF-α, and IL-1β mRNA. Moreover, aPLs(+) IgG stimulated PBMCs and significantly enhanced the production of TNF-α and IL-1β.. These results suggest that IgG-aPLs cause persistently high TF expression and inflammatory cytokine production by interacting with peripheral blood monocytes and lymphocytes, which may be an important mechanism in the pathogenesis of ASO peculiar to SLE patients.

Topics: Adolescent; Adult; Aged; Antibodies, Antiphospholipid; Arteriosclerosis Obliterans; Child; Cytokines; Female; Gene Expression Regulation; Humans; Immunoglobulin G; Leukocytes, Mononuclear; Lupus Erythematosus, Systemic; Male; Middle Aged; Monocytes; Thromboplastin; Tumor Necrosis Factor-alpha; Young Adult

Accelerated atherosclerosis represents a major problem in both systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients, and endothelial damage is a key feature of atherogenesis. We aimed to assess early endothelial changes in SLE and RA female patients (127 SLE and 107 RA) without previous CV events. Biomarkers of endothelial cell activation (intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), thrombomodulin (TM), and tissue factor (TF)) were measured and endothelial function was assessed using peripheral artery tonometry. Reactive hyperemia index (RHI), an indicator of microvascular reactivity, and augmentation index (AIx), a measure of arterial stiffness, were obtained. In addition, traditional CV risk factors, disease activity and medication were determined. Women with SLE displayed higher sICAM-1 and TM and lower TF levels than women with RA (p = 0.001, p<0.001 and p<0.001, respectively). These differences remained significant after controlling for CV risk factors and medication. Serum levels of vascular biomarkers were increased in active disease and a moderate correlation was observed between sVCAM-1 levels and lupus disease activity (rho = 0.246) and between TF levels and RA disease activity (rho = 0.301). Although RHI was similar across the groups, AIx was higher in lupus as compared to RA (p = 0.04). Also in active SLE, a trend towards poorer vasodilation was observed (p = 0.06). In conclusion, women with SLE and RA present with distinct patterns of endothelial cell activation biomarkers not explained by differences in traditional CV risk factors. Early vascular alterations are more pronounced in SLE which is in line with the higher CV risk of these patients.

Topics: Adult; Arthritis, Rheumatoid; Atherosclerosis; Biomarkers; Endothelium, Vascular; Female; Humans; Intercellular Adhesion Molecule-1; Lupus Erythematosus, Systemic; Manometry; Middle Aged; Risk Factors; Thrombomodulin; Thromboplastin; Vascular Cell Adhesion Molecule-1; Vascular Stiffness

Tissue factor (TF) is the main initiator of the coagulation cascade and elements that may upregulate its expression might provoke thrombotic events. Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are autoimmune diseases characterized by a high TF expression in monocytes.. To examine the role of microRNAs (miRNAs) in TF expression and to evaluate their levels in SLE and APS patients.. An in silico search was performed to find potential putative binding sites of miRNAs in TF mRNA. In vitro validation was performed transfecting cells expressing TF (THP-1 and MDA-MB-231) with oligonucleotide miRNA precursors and inhibitors. Additionally, reporter assays were performed to test for the binding of miR-20a to TF mRNA. Levels of miRNAs and TF were measured by quantitative (qRT-PCR) in patients with APS and SLE.. Overexpression of miRNA precursors, but not inhibitors, of two of the members of cluster miR-17∼92, for example miR-19b and miR-20a, in cells expressing TF decreased TF mRNA, protein levels, and procoagulant activity between 30% and 60%. Reporter assays showed that miR-20a binds to TF mRNA. Finally, we measured levels of miR-19b and miR-20a in monocytes from patients with APS and SLE and observed significantly lower miRNAs levels in comparison with healthy subjects inversely correlated with the levels of TF.. Down-regulation of miR-19b and miR-20a observed in patients with SLE and APS could contribute to increased TF expression and thus provoke the hypercoagulable state characteristic of these patients.

Topics: Adult; Aged; Antiphospholipid Syndrome; Blotting, Western; Case-Control Studies; Cell Line; Female; Humans; Lupus Erythematosus, Systemic; Male; MicroRNAs; Middle Aged; Real-Time Polymerase Chain Reaction; Thromboplastin

Thrombosis is a frequent manifestation in patients with systemic lupus erythematosus (SLE), although precise mechanisms remain unclear. This study investigated whether the major physiological trigger of blood coagulation, the tissue factor (TF) pathway, was altered in SLE patients. Furthermore, we investigated potential associations between the TF pathway, the presence of antiphospholipid (APL) antibodies and other abnormalities present in SLE. A total of 101 participants (40 SLE patients and 61 age- and sex-matched controls) were recruited from Tasmania, Australia. Markers of the TF pathway, hypercoagulability, inflammation and endothelial cell damage were measured in plasma. Serum levels of APL antibodies (anti-cardiolipin antibodies [ACL], lupus anticoagulants [LAC], anti-beta2-glycoprotein-1 [anti-β2GP1] and anti-prothrombin antibodies) were also determined. Despite similar TF and TF pathway inhibitor (TFPI) total antigen levels, SLE patients had significantly increased levels of TFPI free antigen (patients vs controls; mean ± SD) (11.6 ± 0.9 ng/mL vs 6.4 ± 0.4 ng/mL; p < 0.001) but significantly reduced TFPI activity (0.66  ± 0.07 U/mL vs 1.22 ± 0.03 U/mL; p < 0.001), compared with healthy controls. Anti-TFPI activity, designated as the ability of isolated IgG fractions to inhibit TFPI activity in normal plasma, was detected in 19/40 (47.5%) of SLE patients and 3/40 (7.5%) of healthy controls. The significant reduction in TFPI activity in SLE patients reflects impaired functional control of the TF pathway. Moreover, SLE patients with a history of thrombosis demonstrated higher levels of TFPI activity compared with patients without a previous thrombotic event (0.97 ± 0.07 U/mL vs 0.53 ± 0.14 U/mL; p = 0.0026). Changes to the TF pathway were not associated with manifestations of SLE such as inflammation or endothelial cell damage. The results from this study suggest hypercoagulability in SLE may (in part) be due to reduced TFPI activity, a mechanism that appears to be independent of other abnormalities in SLE.

Topics: Adult; Aged; Antibodies, Antiphospholipid; Biomarkers; Blood Coagulation; Case-Control Studies; E-Selectin; Female; Humans; Interleukin-6; Lipoproteins; Lupus Erythematosus, Systemic; Male; Middle Aged; Thrombin; Thromboplastin; Tumor Necrosis Factor-alpha

Our aim was to clarify the role of anti-phospholipid antibodies in the pathogenesis of monocyte tissue factor (TF) expression and thromboembolic complications (TE) in patients with SLE. We examined cell surface expression of TF on monocytes in 93 SLE patients. Monocyte TF expression was significantly higher in SLE patients who had TE than in other SLE patients, and confirmed that the high expression of monocyte TF was a strong risk factor for TE. Furthermore, the presence of anti-cardiolipin/beta2-glycoprotein I antibodies (anti-CL/beta2-GPI) was strongly associated with the high expression of monocyte TF. We therefore studied the in vitro effect of IgG anti-CL/beta2-GPI on lipopolysaccharide (LPS)-induced expression of TF on monocytes in healthy peripheral blood and found that purified IgG containing anti-CL/beta2-GPI significantly enhanced LPS-induced monocyte TF expression. These results suggest that anti-CL/beta2-GPI cause persistently high TF expression on monocyte, which may contribute to the risk of thromboembolic events in SLE patients.

Topics: Adolescent; Adult; Aged; Antibodies, Antiphospholipid; Child; Female; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Monocytes; Risk Factors; Thromboembolism; Thromboplastin

Women with systemic lupus erythematosus (SLE) are at risk for premature atherothrombosis independent of Framingham risk factors. We investigated whether endothelial cell (EC) apoptosis predicts abnormal vasomotor tone and contributes to circulating tissue factor (TF) levels in this disease. Brachial artery flow-mediated dilation (FMD) and nitroglycerin-mediated dilation were determined in women with SLE, healthy control subjects, and subjects with coronary artery disease (CAD) (n = 43/group). Quantification of circulating apoptotic ECs was performed by flow cytometry (CD146(+) cells that stained for Annexin V [CD146(AnnV+)]) and immunofluorescent microscopy. Plasma TF was measured by enzyme-linked immunosorbent assay (ELISA). Compared with healthy control and CAD subjects, patients with SLE had higher numbers of circulating CD146(AnnV+) cells (10 +/- 3, 18 +/- 5, and 89 +/- 32 cells/mL, respectively, mean +/- SEM; P <.01). Increased CD146(AnnV+) cells correlated strongly with abnormal vascular function (P =.037). After adjusting for known predictors of endothelial function, CD146(AnnV+) was the only variable that predicted FMD (beta = -4.5, P <.001). Increased CD146(AnnV+) was strongly associated with elevated levels of circulating TF (r =.46, P =.002). Circulating apoptotic ECs are elevated in young women with SLE and strongly correlate with markedly abnormal vascular function and elevated TF levels. Heightened endothelial apoptosis may represent an important mechanism for development of atherothrombosis in SLE.

Topics: Adult; Aged; Apoptosis; Blood Circulation; Case-Control Studies; Endothelial Cells; Endothelium, Vascular; Female; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Thromboplastin; Thrombosis; Vascular Diseases; Vasodilation

Activated protein C resistance (APCR), high tissue factor (TF) expression, and hyper-homocysteinemia are associated with thromboembolic diseases. Thromboembolism is a frequent complication of systemic lupus erythematosus (SLE). In this study, we evaluated the prevalence of APCR, high TF, and homocysteine with correlation of the thrombotic tendency in SLE. Ninety-four SLE patients and 28 normal controls were included. APC ratio and TF antigen were measured using commercial kits. Plasma homocysteine level was measured using HPLC. The prevalence of APCR, high TF antigen level, and hyper-homocysteinemia in our SLE patients were 21.3%, 66.0%, and 23.4%, respectively. The median plasma level of TF antigen in SLE patients was 145.23 pg/mL (range, 31.00-778.50 pg/mL), which was significantly higher than the control value of 39.83 pg/mL (range, 1.55-168.50 pg/mL). The median APC ratio in SLE patients was 2.76 (range, 1.48-13.47), which was significantly lower than the control value of 3.59 (range, 0.26-5.66). The plasma level of homocysteine was not significantly different from that of control. A significant association was observed between the presence of APCR (OR = 8.59, P < 0.0001) but not with the presence of high plasma TF antigen level (OR = 1.24, P = 0.67) and thrombotic complications in SLE patients. In conclusion, APCR and high plasma TF levels are common in SLE, but a significant association was observed only between the presence of APCR and thrombosis in SLE patients.

Topics: Activated Protein C Resistance; Adolescent; Adult; Aged; Aged, 80 and over; Case-Control Studies; Female; Homocysteine; Humans; Hyperhomocysteinemia; Lupus Erythematosus, Systemic; Male; Middle Aged; Prevalence; Retrospective Studies; Thromboembolism; Thromboplastin; Thrombosis

It is well known that monocytes may play an active role in thrombogenesis, since they may express on their surface tissue factor, the major initiator of the clotting cascade. The results of this investigation demonstrate beta-2-glycoprotein I (beta2-GPI) mRNA expression by human peripheral blood monocytes, indicating that these cells synthesize beta2-GPI. In addition, we show beta2-GPI expression on cell surface of these cells by flow cytometric analysis, and the presence of this protein in cell lysate by Western blot. Interestingly, beta2-GPI expression on monocytes is significantly increased in patients with anti-phospholipid syndrome (APS) or systemic lupus erythematosus (SLE) as against healthy blood donors and correlates with tissue factor expression on monocytes. These findings support the view that monocytes are able to synthesize beta2-GPI and suggest that patients with APS may have increased beta2-GPI exposure on cell surface, which leads to persistently high monocyte tissue factor expression and consequently to a prothrombotic diathesis.

Topics: Adolescent; Adult; Antiphospholipid Syndrome; Autoantibodies; beta 2-Glycoprotein I; Blotting, Western; Child; DNA Fragmentation; Female; Flow Cytometry; Fluorescent Antibody Technique, Indirect; Gene Expression; Glycoproteins; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Monocytes; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thromboplastin

Clinicians commonly evaluate patients with thrombosis or a prolonged activated partial thromboplastin time (aPTT) for the presence of a lupus anticoagulant (LA). We evaluated strategies for detecting LA, in three clinical settings, with decision-modeling techniques. A decision tree was constructed with 12 strategies, using a combination of aPTT and dilute Russell viper venom times (dRVVT) with confirmatory tests, tissue thromboplastin time (TTI), platelet neutralization procedures, and mixing studies. Probabilities and costs of adverse events and test costs were obtained from the literature. Patient preference for each strategy was evaluated by assigning utilities to each outcome. On the basis of assay results in 90 healthy people and 77 patients, we calculated sensitivities and specificities for each strategy, with true positives defined as suggested by the International Society on Thrombosis and Haemostasis. The least costly strategy for evaluation of patients with a prolonged aPTT, or with thrombosis, is not to test and to assume that LA is absent. For patients with systemic lupus erythematosus (SLE), it is least expensive not to test, although testing with TTI alone can also be considered an efficient strategy. The strategy of highest utility to patients with SLE is testing with TTI, followed by dRVVT. On the basis of these cost and utility results, clinicians' strategies for detecting LA may need modification. These strategies would then optimally be tested in clinical trials.

Topics: Abortion, Spontaneous; Autoantibodies; Costs and Cost Analysis; Decision Trees; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Partial Thromboplastin Time; Prothrombin Time; Sensitivity and Specificity; Thromboplastin; Thrombosis

We investigated the mechanism by which anti-prothrombin antibodies cause lupus anticoagulant (LAC) activity. Addition of affinity-purified anti-prothrombin antibodies from LAC-positive plasma samples (alpha-FII-LAC+) to normal plasma induced LAC activity. Upon increasing the phospholipid concentration, LAC activity was neutralized. Addition of purified alpha-FII-LAC+ to normal plasma strongly inhibited factor Xa formation. No inhibition was measured when alpha-FII-LAC+ were added to prothrombin-deficient plasma or when purified anti-prothrombin antibodies from LAC-negative plasma samples (alpha-FII-LAC-) were added. When a combination of prothrombin and alpha-FII-LAC+ was added to the purified clotting complex, a strong inhibition of factor Xa and IIa formation was seen. The alpha-FII-LAC+ alone or a combination of prothrombin and alpha-FII-LAC- did not show inhibition. Ellipsometry studies showed that, in the presence of alpha-FII-LAC+, the affinity of prothrombin for a phospholipid surface increased dramatically, whereas a much lower increase was observed with alpha-FII-LAC-. Our results show that complexes of prothrombin and anti-prothrombin antibodies with LAC activity inhibit both prothrombinase and tenase. The antibodies increase the affinity of prothrombin for the phospholipid surface, thereby competing with clotting factors for the available catalytic phospholipid surface, a mechanism similar to that of anti-beta2-glycoprotein I antibodies.

Topics: Antiphospholipid Syndrome; Autoantibodies; Cysteine Endopeptidases; Enzyme-Linked Immunosorbent Assay; Factor Xa; Female; Humans; Lipid Bilayers; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Neoplasm Proteins; Phospholipids; Protein Binding; Prothrombin; Thromboplastin

Two human monoclonal antiphospholipid antibodies (APA) of the IgG type, HL-5B and RR-7F have been generated from a patient with primary antiphospholipid syndrome and recurrent cerebral microemboli (H.L.) and from a patient with SLE without evidence of recurrent thrombosis (R.R.). Both monoclonal APA have similar characteristics in ELISA tests. To further analyse the prothrombotic potential, their effect on human monocytes and platelets, and bovine aortic endothelial cells (BAEC) was investigated. Monocytes were isolated from buffy coats by standard techniques. They were incubated either with the respective monoclonal APA in different concentrations, or a control monoclonal IgG of the same subtype, or plasma of the patients, from whom the antibodies were isolated. Incubation with LPS served as positive control. BAEC were grown to confluence, and then incubated with the appropriate agonists. Procoagulant activity (PCA) was determined by a single stage clotting assay. PCA expression after incubation is given as the ratio of the coagulation times observed with media only divided by that observed with the agonist. A PCA ratio >1 indicates the induction of PCA by the agonist. At 1 microg/ml HL-5B yielded a PCA ratio of 1.63 +/- 0.16 while RR-7F induced no significant rise to 1.06 +/- 0.18. Dose response curves showed that RR-7F can induce PCA at higher concentrations. However, its effect is approx. 1/50 of HL-5B based on equimolar antibody concentration. Further analysis indicates that the majority of the PCA induced by monoclonal APA can be inhibited by a specific tissue factor antibody. Neither monoclonal antibody induced PCA in BAEC. Sera from both patients were able to induce PCA in monocytes. However, the PCA ratio of serum from H.L. was higher (1.78) than that of R.R. (1.44). Neither monoclonal APA had an effect on platelets as determined by flow cytometric analysis of CD62P, CD41, CD42b expression and fibrinogen binding with and without previous activation with 5 microM ADP or 15 microM TRAP-6. Similarly, there were no differences in platelet aggregation to different stimuli including submaximal activation. In summary, these data provide further evidence that induction of tissue factor in monocytes is one of the procoagulant effects of APA. Furthermore, the binding specificity of APA is perhaps not suited to predict the biological effects of the antibodies.

Topics: Adenosine Diphosphate; Animals; Antibodies, Antiphospholipid; Antibodies, Monoclonal; Antibody Specificity; Antiphospholipid Syndrome; Autoimmune Diseases; Biomarkers; Blood Coagulation Factors; Blood Platelets; Cattle; Cells, Cultured; Dose-Response Relationship, Immunologic; Endothelium, Vascular; Female; Fibrinogen; Humans; Immunoglobulin G; Intracranial Embolism; Lipopolysaccharides; Lupus Erythematosus, Systemic; Male; Middle Aged; Monocytes; Peptide Fragments; Platelet Activation; Recurrence; Thrombophilia; Thromboplastin

Anti-beta 2-glycoprotein I antibodies bind to endothelial cells through beta 2-GPI. The antibodies are present in patients with systemic lupus erythematosus and antiphospholipid syndrome and are associated with the pathogenesis of the disease. Anti-endothelial cell antibodies that react with constitutive antigens on ECs are present in patients with vasculiditis and other diseases. Both types of antibodies can activate ECs. Frequent findings in APLS and vasculitis are fibrin deposits and thromboembolic phenomena. These indicate that the coagulation system is activated. However, the mechanism of activation is not clear. ECs generate tissue factor upon stimulation with various substances. In the present study we report that monoclonal anti-beta 2-GPI antibodies and AECAs, derived from a patient with primary APLS and a patient with Takayasu's arteritis, respectively, induce a potent tissue factor in ECs. The production of TF activity, TF antigen and TF mRNA is dose and time dependent. The TF activity was induced also by F(ab)2 but not by Fc fragments and was abolished completely by pre-incubation with ant-TF antibodies. The TF that is induced in ECs by AECAs with and without beta 2-GPI specificity may activate the coagulation and thereby play a major role in the pathogenesis of fibrin deposition and thrombus formation in diseases that are associated with the presence of these antibodies.

Topics: Antibodies; Antigens; Antiphospholipid Syndrome; Apolipoproteins; beta 2-Glycoprotein I; Binding Sites, Antibody; Cells, Cultured; Endothelium, Vascular; Fibrin; Glycoproteins; Humans; Immunoglobulin Fab Fragments; Immunoglobulin Fc Fragments; Lupus Erythematosus, Systemic; Membrane Glycoproteins; RNA, Messenger; Takayasu Arteritis; Thromboembolism; Thromboplastin; Vasculitis

Tissue factor (TF) is the major intrinsic initiator of clotting. TF expression on monocytes has been associated with high titers of anticardiolipin antibodies (aCL) in patients with antiphospholipid syndrome (APS) with thrombosis. We investigated the influence of clinical factors on TF activity in blood from patients with systemic lupus erythematosus (SLE) and examined the relationship between aCL and TF.. In this cross sectional study, consecutive patients with SLE from one rheumatology clinic gave blood samples for measurement of TF activity, aCL, and Russell viper venom time. We assessed disease activity by measuring sedimentation rate, anti-dsDNA, and complement components C3 and C4, and measured clinical indices. Associations were investigated with the Wilcoxon rank-sum test and linear regression.. Sixty-nine patients contributed blood samples. The median age was 38 years, and 10 of the SLE patients had a history of thrombosis. Patients with active arthritis had TF activity 1.3 times that in patients without arthritis (p = 0.028). Users of nonsteroidal antiinflammatory drugs (NSAID) had TF activity significantly lower than nonusers (p = 0.010). Patients with previous thrombosis had TF activity significantly lower than patients without thrombosis (p < 0.001). Overall, aCL and TF activity were not associated when we adjusted for these clinical factors.. Arthritis, previous thrombosis, and use of NSAID significantly modified TF activity in patients with SLE. Unlike previous reports, we found no association between aCL titer and TF activity, which may be due to our adjusting for other important clinical factors.

Topics: Adolescent; Adult; Aged; Anti-Inflammatory Agents, Non-Steroidal; Antibodies, Anticardiolipin; Arthritis; Cross-Sectional Studies; Disease Progression; Female; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Thromboplastin; Thrombosis

Microparticles (MPs) resulting from vesiculation of platelets and other blood cells have been extensively documented in vitro and have been found in increased numbers in several vascular diseases, but little is known about MPs of endothelial origin. The aim of this study was to analyze morphological, immunological, and functional characteristics of MPs derived from human umbilical vein endothelial cells (HUVECs) stimulated by TNF, and to investigate whether these MPs are detectable in healthy individuals and in patients with a prothrombotic coagulation abnormality. Electron microscopy evidenced bleb formation on the membrane of TNF-stimulated HUVECs, leading to increased numbers of MPs released in the supernatant. These endothelial microparticles (EMPs) expressed the same antigenic determinants as the corresponding cell surface, both in resting and activated conditions. MPs derived from TNF-stimulated cells induced coagulation in vitro, via a tissue factor/factor VII-dependent pathway. The expression of E-selectin, ICAM-1, alphavbeta3, and PECAM-1 suggests that MPs have an adhesion potential in addition to their procoagulant activity. In patients, labeling with alphavbeta3 was selected to discriminate EMPs from those of other origins. We provide evidence that endothelial-derived MPs are detectable in normal human blood and are increased in patients with a coagulation abnormality characterized by the presence of lupus anticoagulant. Thus, MPs can be induced by TNF in vitro, and may participate in vivo in the dissemination of proadhesive and procoagulant activities in thrombotic disorders.

Topics: Antiphospholipid Syndrome; Autoimmune Diseases; Cell Adhesion Molecules; Cells, Cultured; Endothelium, Vascular; Factor VII; Flow Cytometry; Humans; Infections; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Microscopy, Confocal; Neoplasms; Receptors, Vitronectin; Thrombophilia; Thromboplastin; Tumor Necrosis Factor-alpha; Umbilical Veins

To evaluate the relationship between the tissue factor (TF) pathway and lupus anticoagulant (LA), in the present study, we measured the plasma levels of TF antigen and TF pathway inhibitor (TFPI) antigen in patients positive for LA. Plasma TF and TFPI levels in LA-positive patients were significantly higher than levels in healthy volunteers (p < 0.01). In LA-positive patients, there were no significant differences in plasma TF and TFPI levels between patients with and without thrombosis. In patients with thrombosis, there was no significant difference in the plasma TF level between LA-positive and LA-negative patients; however, the plasma TFPI level in LA-positive patients was significantly lower than that in LA-negative patients (p < 0.01). We also examined the TF pathway in human umbilical venous endothelial cells (HUVEC) incubated with plasma of LA-positive patients, LA-negative patients, and healthy volunteers. TF activity was significantly higher (p < .05) in HUVECs incubated with the plasma of LA-positive patients than in cells incubated with the plasma of the other two groups (p < .01). However, there was no significant difference in TFPI antigen levels among the media of HUVECs incubated with the plasma of all groups. The viability of HUVEC incubated with the plasma of LA-positive patients with thromboses, LA-positive patients without thromboses, and LA-negative patients with thromboses were significantly lower than that of HUVECs incubated with the plasma of healthy volunteers (p < .01). These findings suggest that abnormalities of the TF pathway plays an important role in the mechanism of hypercoagulability in LA-positive patients. LA may affect vascular endothelial cells causing thrombogenesis.

Topics: Adult; alpha-2-Antiplasmin; Anticoagulants; Antifibrinolytic Agents; Antigens; Antithrombin III; Cell Culture Techniques; Cell Survival; Cohort Studies; Endothelium, Vascular; Factor Xa Inhibitors; Female; Fibrin Fibrinogen Degradation Products; Fibrinolysin; Fibrinolytic Agents; Hemostatics; Humans; Lipoproteins; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Middle Aged; Peptide Hydrolases; Serine Proteinase Inhibitors; Thromboplastin; Thrombosis; Umbilical Veins

We determined the prevalence and relationship with clinical manifestations of antibodies to thromboplastin (aTP) in 92 patients with systemic lupus erythematosus (SLE). Thirty-two (35%) patients had aTP: 13 (14%) were positive for IgG aTP, 13 (14%) for IgM aTP, and 6 (7%) for both. Patients with aTP had an increased incidence of thrombosis (p = 0.01), thrombocytopenia (p < 0.001), hemolytic anemia (p < 0.001), and fetal losses (p = 0.03). When the IgG and IgM aTP isotypes were analysed separately, the IgG aTP were found to be associated with thrombosis (p < 0.001), thrombocytopenia (p < 0.001), and fetal losses (p = 0.02). The IgM aTP were associated with hemolytic anemia (p < 0.001). A correlation was found between the titers of aTP and those of anticardiolipin antibodies, in both IgG (p < 0.01, r = 0.6) and IgM (p < 0.01, r = 0.64) isotypes, and between the titers of IgG aTP and the diluted Russell's viper venom time used to detect the lupus anticoagulant (p < 0.001, r = 0.42). This test is a reliable, reproducible and sensitive assay for the detection of antiphospholipid antibodies, specially in those patients under anticoagulant therapy.

Topics: Adolescent; Adult; Aged; Anemia, Hemolytic, Autoimmune; Antibodies, Anticardiolipin; Antiphospholipid Syndrome; Autoantibodies; Case-Control Studies; Cohort Studies; Enzyme-Linked Immunosorbent Assay; Female; Fetal Death; Humans; Immunoglobulin G; Immunoglobulin Isotypes; Immunoglobulin M; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Middle Aged; Pregnancy; Reproducibility of Results; Sensitivity and Specificity; Thrombocytopenia; Thromboplastin; Thrombosis

The identification of the presence of antiphospholipid in plasma is recognised to be of diagnostic and prognostic importance in subjects with thrombotic disease, recurrent miscarriage or collagen vascular disorders. A number of coagulation assays are currently employed for the detection of lupus anticoagulant (LA), many of which are influenced by reagent dependent and methodological variables. In the present study lyophilised plasma samples from three subjects with "strong", "weak" and "absent" LA were tested in 220 centres. The most commonly used tests for LA were Activated Partial Thromboplastin Time (APTT), Dilute Russell Viper Venom Time (DRVVT) and Kaolin CLotting Time (KCT). Median DRVVT ratios were 1.75, 1.17 and 1.10 for the three samples. The presence of a strong LA was not detected by 4% of laboratories. The correct diagnosis was made by 94% of users of DRVVT and 85% of users of KCT. A weak LA was not detected by over half of centres. Correction was observed on addition of plasma and also in platelet neutralisation. The correct diagnosis was made by 37% of users of DRVVT and 27% of users of KCT. Lupus Anticoagulant was falsely considered to be present in a Factor IX deficient plasma by approximately one quarter of laboratories. Amongst users of DRVVT and KCT absence of LA in this sample was correctly reported by 73% and 69% of centres respectively. The accuracy of testing for LA in the present study is suboptimal and this is likely to have important clinical consequences. There is clearly a need for greater conformity in the selection and performance of LA tests to facilitate accurate diagnosis of this important group of disorders.

Topics: Antiphospholipid Syndrome; Blood Coagulation; Blood Coagulation Tests; Diagnosis, Differential; Embolism; Female; Hemophilia B; Heterozygote; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Partial Thromboplastin Time; Quality Control; Reproducibility of Results; Retinal Vessels; Thromboplastin; United Kingdom

We developed a novel assay using human thrombomodulin (TM), which detected overall abnormalities in the protein C anticoagulant pathway (PC pathway). This assay indicates the degree of inhibition of prothrombinase by TM, which is represented as the percentage of prothrombinase inhibition by 25 ng/ml of TM, termed PIP25 (Prothrombinase Inhibition Percentage). We examined PIP25 in plasma samples from patients with systemic lupus erythematosus (SLE) with or without lupus anticoagulant (LA), patients with Behcet's disease (BD), and patients with miscellaneous thrombotic vasculitis and compared these with the PIP25 of plasma samples from healthy volunteers in Japan. The PIP25S were significantly lower in SLE alone (35.5 +/- 12.8%, P = 0.036) and SLE with LA (33.0 +/- 13.3%, P = 0.030) and BD (33.3 +/- 13.4%, P = 0.010) than those in healthy volunteers (43.5 +/- 10.7%). There was no significance between healthy PIP25 and those with miscellaneous thrombotic vasculitis (44.2 +/- 8.4%, P = 0.823). These results suggest that the abnormalities of the protein C anticoagulant pathway were present in patients with SLE(LA) and BD.

Topics: Behcet Syndrome; Blood Coagulation; Cryopreservation; Female; Humans; Immunoassay; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Plasma; Protein C; Recombinant Proteins; Specimen Handling; Thrombomodulin; Thromboplastin; Thrombosis

Topics: Blood Coagulation; Blood Coagulation Tests; France; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Monitoring, Physiologic; Prothrombin Time; Thromboplastin

Topics: Abortion, Habitual; Animals; Autoantibodies; Blood Coagulation Factors; Blood Coagulation Tests; Cardiolipins; Cattle; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Immunoglobulin M; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Phospholipids; Pregnancy; Thromboplastin

The dilute tissue thromboplastin inhibition (DTTI) test (Schleider et al, 1976) is a sensitive but non-specific test for lupus anticoagulant (LA). False positive results are seen in patients with clotting factor deficiency involving the extrinsic pathway and also in some patients with specific factor inhibitors (Triplett et al, 1983; Rosove et al, 1986). Since the effect of LA is phospholipid dependent but those of factor deficiency and specific inhibitors are not, we analyse the test results by comparing the degree of inhibition using different dilutions of tissue thromboplastin and express it as the DTTI index. This is defined as the clotting time ratio with 0.2% tissue thromboplastin divided by the clotting time ratio with 2% tissue thromboplastin. We also perform a dilute tissue thromboplastin time with platelet substitution to see if this could neutralize the inhibition caused by LA. Both of these modifications can reliably distinguish LA from other conditions associated with prolonged APTT better than the original DTTI test.

Topics: Adolescent; Adult; Blood Coagulation Factors; Blood Coagulation Tests; Female; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Thromboplastin; Time Factors

Prothrombinase activity was analysed in the plasma of a series of patients with lupus anticoagulants (LAC). In the presence of purified PS-PC (20-80%) vesicles the prothrombinase activity triggered by kaolin was retarded by 2-3 min with respect with normal plasma. The maximal values of prothrombinase activity increased by increasing the amount of phospholipid vesicles. However, in the plasma of the patients they were always lower than those of normal plasma at each phospholipid concentration. Platelet-dependent prothrombinase activity was subsequently investigated. Again, both a delay in appearance and reduced peak values of prothrombinase activity were observed in the plasma of the patients. This inhibition was partially overcome by the addition of an excess of purified phospholipids. Finally, the effect of LAC IgG on platelet rich plasma-dependent prothrombinase activity was investigated. The main effect observed was a delay of the peak time of prothrombinase activity, while the maximal peaks were affected only by one IgG preparation. We conclude that LAC antibodies can react with both purified negatively-charged phospholipids and platelet procoagulant phospholipids and inhibit prothrombinase activity in a similar way in both cases.

Topics: Adult; Antibodies; Blood Coagulation; Blood Coagulation Factors; Blood Platelets; Female; Humans; Immunoglobulin G; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Middle Aged; Phospholipids; Thromboplastin

A disturbance in endothelial cell (EC) function may be pathogenetic in the thrombotic tendency of patients with the lupus anticoagulant (LA). The ability of serum from normal subjects and patients with systemic lupus erythematosus (SLE), with and without the LA, to modulate the release of prostacyclin (PGI2) and the expression of procoagulant activity by cultured human EC was investigated. Only the 10% and 20% serum concentrations from patients with SLE-LA produced a significantly greater inhibition of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) release (the stable metabolite of PGI2) than control serum. However, when patients with SLE-LA having Raynaud's phenomenon were excluded from this group, there was then no significant difference between the effect of the patient and control serum. Serum from patients with SLE +/- LA caused a significant increase in EC procoagulant activity compared to healthy controls. The two-stage partial thromboplastin time expressed in seconds decreased from 66 (normal) to 34 (SLE - LA) and 31 (SLE + LA), but there was no significant difference between the patients with and without the LA. The significantly increased EC procoagulant activity induced by serum from patients with SLE +/- LA may account for the observed increased incidence of thrombotic events in patients with SLE. Our data suggest that factors other than decreased prostacyclin release are responsible for the altered hemostasis observed in patients with SLE + LA.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Blood Coagulation Factors; Endothelium; Epoprostenol; Female; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Middle Aged; Thromboplastin

A solid phase ELISA was developed to investigate the association between anticardiolipin antibodies and lupus anticoagulant in pregnancy. Twenty-seven pregnant women with a history of recurrent fetal losses or systemic lupus erythematosus (SLE) were tested for the presence of lupus anticoagulant, anticardiolipin antibodies, antinuclear antibodies (ANA) and anti-single-stranded DNA antibodies. Nineteen women with a total of 49 previous unsuccessful pregnancies were found to have lupus anticoagulant and anticardiolipin antibodies. Three women who had suffered four fetal deaths from six pregnancies had anticardiolipin antibodies without lupus anticoagulant. Cardiolipin antibodies were not detected in the remaining five patients. This assay for measuring anticardiolipin antibodies appears to provide a simple and inexpensive method of identifying women at risk of fetal death from the adverse effects of lupus anticoagulant.

Topics: Abortion, Habitual; Antibodies; Antigens, Surface; Autoantibodies; Blood Coagulation Factors; Cardiolipins; Enzyme-Linked Immunosorbent Assay; Female; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Pregnancy; Pregnancy Complications; Thromboplastin

Topics: Adult; Blood Coagulation Factors; Female; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Pregnancy; Pregnancy Complications; Pulmonary Embolism; Thrombophlebitis; Thromboplastin

The clinical and laboratory findings in seven female patients with primary autoimmune diseases, one female patient with lymphoplasmacytoid (LP) immunocytoma and IgM paraproteinemia, and two male patients with multiple myeloma are described. The common denominator in all patients was a lupus anticoagulant or a closely related coagulation disorder. Recurrent thrombosis was observed in six patients with autoimmune diseases and in two patients with malignant monoclonal gammopathies. Other clinical manifestations included cerebral disorders (four patients with autoimmune disease/two patients with monoclonal gammopathy), repeated obstetric complications (6/1), asymptomatic valvular heart disease (6/1), renal dysfunction (6/2), hepatic involvement (2/2), and arthropathy (2/0). Laboratory investigations revealed a biologic false-positive serological test for syphilis in six patients with autoimmune disease and one with monoclonal gammopathy, antinuclear antibodies (4/0), antibodies against DNA (4/1), and a positive direct Coombs test (3/1) which was accompanied by hemolytic anemia in two patients (1/1). Additionally slight leukocytopenia (2/1) and thrombocytopenia (6/2) were observed; abnormal bleeding was only seen in one patient with severe thrombocytopenia. Other complications characteristic of LP immunocytoma or multiple myeloma were missing. The obvious similarities between the patients with autoimmune diseases and the patients with malignant monoclonal gammopathies suggest analogous pathogenetic mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Abortion, Spontaneous; Autoantibodies; Autoimmune Diseases; Blood Coagulation Factors; Blood Coagulation Tests; Brain Diseases; Female; Humans; Immunoglobulins; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Lymphoma; Multiple Myeloma; Paraproteinemias; Pregnancy; Thromboplastin; Thrombosis

Circulating lupus anticoagulant occurs in 5-37% of all patients with systemic lupus erythematosus. Its occurrence is not restricted to collagen vascular disease states. Lupus anticoagulant causes a prolongation of certain laboratory coagulation studies yet it is associated in vivo with a history of systemic intravascular thromboses. Placental vessels are also affected. Less than one in six pregnancies complicated by the presence of this auto-antibody is successful. Treatment of afflicted parturients with anti-platelet therapy has increased perinatal survival rates. Derangements in the coagulation profile and concomitant anti-platelet therapy confound the rational use of regional anaesthesia in the management of labour and delivery in these high-risk pregnancies.

Topics: Adult; Anesthesia, General; Anesthesia, Obstetrical; Autoantibodies; Blood Coagulation Factors; Female; Humans; Infant, Newborn; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Obstetric Labor Complications; Pregnancy; Thromboplastin

Antiphospholipid antibodies have been determined in two groups of 48 sera from patients with systemic lupus erythematosus (SLE) and syphilis. Using an ELISA, IgG anticardiolipin (CL), antiphosphatidyl serine (PS) and antiphosphatidyl ethanolamine (PEA), antibodies have been detected with the same frequency in both groups of patients. Titres of antiphosphatidyl serine (PS) (p less than 0.005) and PEA antibodies (p less than 0.05) were significantly higher in the syphilitic sera compared to the SLE sera. Anticardiolipin binding activity of both groups of sera could be inhibited by preincubation with phosphatidic acid, phosphatidyl serine, phosphatidyl glycerol and cardiolipin antigens, but the inhibiting ratio of phosphatidyl antigen was significantly higher (p less than 0.01) in the SLE group. These data suggest that anticardiolipin auto-antibodies present in SLE sera are very similar to the "reagins" or antibodies to cardiolipin seen in syphilitic sera. IgG anticardiolipin antibodies may be an epiphenomenon and are probably not implicated in the pathogenesis of the thrombotic diathesis seen preferentially in some patients with SLE.

Topics: Antibodies; Antibody Specificity; Autoantibodies; Blood Coagulation Factors; Cross Reactions; Female; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Male; Phospholipids; Syphilis; Thromboplastin; Thrombosis

An acutely ill 4-year-old girl with Rocky Mountain spotted fever (RMSF) was found to have a coagulation inhibitor. This child had no serious bleeding manifestations and minimal hemorrhagic skin manifestations despite severe RMSF, concurrent thrombocytopenia, as well as the coagulation inhibitor. Hemostatic abnormalities that occur with RMSF as well as other infectious illnesses associated with coagulation inhibitors are reviewed.

Topics: Autoantibodies; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Child, Preschool; Female; Humans; Lupus Erythematosus, Systemic; Partial Thromboplastin Time; Rocky Mountain Spotted Fever; Thromboplastin

The physiopathological role of antithromboplastin-type circulating anticoagulants in habitual abortion may be envisaged since the presence of antithromboplastin has been reported in most studies on women at high risk of abortion. To avoid a possible statistical bias, we conducted a prospective study in a sufficiently large group of women with habitual abortion (n = 99) compared with a control group of women with normal fecundity (n = 50). In addition, all women were investigated for lupus symptoms. The circulating antibody was detected by the diluted thromboplastin time and activated cephalin time methods. The results were considered positive when the patient/control diluted thromboplastin time ratio was 1.2 and/or when the increase in activated cephalin time was not corrected by a control plasma. In the patients' group, 10 women (10%) had an anti-thromboplastin type circulating anticoagulant, whereas no circulating anticoagulant could be detected in the control group. Three women with circulating anticoagulant had signs of systemic lupus erythematosus. None of the patients presented with Soulier-Boffa syndrome. These data have established a significant correlation between habitual abortion and circulating anticoagulant whilst avoiding statistical bias. Our results suggest that women with idiopathic habitual abortion should be subjected to systematic immunological exploration and that a small number of them should be followed attentively.

Topics: Abortion, Habitual; Antibodies, Antinuclear; Autoantibodies; Blood Coagulation Disorders; Female; Hemostasis; Humans; Immunoglobulins; Lupus Erythematosus, Systemic; Partial Thromboplastin Time; Pregnancy; Prospective Studies; Thromboplastin

We utilized a kaolin-activated partial thromboplastin time (APTT) using rabbit brain phospholipid, in which the capacity of a fourfold increased "high" phospholipid concentration (PC) to normalize the abnormal "standard" PC-APTT in patients with lupus anticoagulants is assessed. This system was also used to measure factors VIIIC, IX, and XI. The tissue thromboplastin inhibition test (TTI), a prothrombin time system in which the activity of a lupus anticoagulant is unmasked by the use of dilute thromboplastin, was simultaneously evaluated. Test sensitivity was defined by results on 31 consecutive patients with standard PC-APTT inhibitors and no bleeding tendency. Specificity was based on 94 patients with various other coagulopathies, including coagulation factor inhibitors, severe congenital factor deficiencies, hepatic insufficiency, and warfarin and heparin treatment. Twenty-one patients with lupus erythematosus and standard PC-APTT results within normal limits were also tested. Sensitivity of the APTT system was superior to that of the TTI (97% v 58%); high PC normalized clotting time ratios and factor levels. Positive results were common with both assays in the group of 20 heparinized patients. The APTT system had superior specificity in remaining cases; there were no positive tests among 74 patients. The lupus erythematosus group had a significant decrease in the clotting time ratio with high PC, indicating that low-level lupus anticoagulants are quite prevalent in this group. The kaolin clotting time using rabbit brain phospholipid in standard and high concentrations is a simple, sensitive, and specific technique for diagnosis of lupus anticoagulants.

Topics: Animals; Blood Coagulation; Brain Chemistry; Humans; Lupus Erythematosus, Systemic; Methods; Partial Thromboplastin Time; Phospholipids; Prothrombin; Rabbits; Thromboplastin

Patients with systemic lupus erythematosus (SLE) have an increased incidence of arterial and venous thromboses. The mechanism by which thromboses develop in these patients is unknown. We had previously observed that the sera of patients with SLE contain antibodies and immune complexes that can bind to endothelial cells. Because endothelial cells can synthesize tissue factor, a potent activator of coagulation, we studied the effect of IgG complexes and sera from patients with SLE on the production of tissue factor by these cells. Human umbilical venous endothelial cells incubated with heat-aggregated IgG (HA-IgG) (0.5 to 4.0 mg) elaborate procoagulant activity in a dose-dependent manner. All procoagulant activity was found in the particulate cell fraction, and none was secreted into the medium. Maximum expression of procoagulant activity required 6 to 8 hr, and its production was totally inhibited by the addition of cyclohexamide or actinomycin D. The presence of gel-filtered platelets augmented production of procoagulant activity by endothelial cells stimulated by HA-IgG. Endothelial cell procoagulant activity was not inactivated by diisofluoropropylphosphate, required the presence of Factor VII for its expression, and was neutralized by a specific anti-tissue factor antibody. Endothelial cells incubated with sera from 14 of 16 patients with SLE produced increased amounts of tissue factor compared with 21 normal sera (p less than 0.025). Fractions of two SLE sera containing monomeric IgG, IgA, or IgM, as well as fractions containing IgG complexes, each stimulated endothelial cells to produce more tissue factor than similar fractions prepared from two normal sera. These studies demonstrate that endothelial cells will produce the procoagulant tissue factor after exposure to anti-endothelial cell antibodies or IgG-containing immune complexes. The production of tissue factor by endothelial cells at sites of immune vascular injury may play a role in the development of thromboses in patients with SLE.

Topics: Antibodies; Antigen-Antibody Complex; Cells, Cultured; Endothelium; Humans; Immunoglobulin G; Lupus Erythematosus, Systemic; Thromboplastin; Thrombosis; Umbilical Veins

Mixtures of various patient lupus inhibitor-containing plasmas and normal plasma were tested concurrently with the dilute tissue thromboplastin inhibition (DTTI) test and the kaolin clotting time (KCT). The KCT was found to be more sensitive to the presence of the lupus inhibitor than the DTTI. The principle of reducing the platelet phospholipid content in the KCT test plasma to enhance sensitivity for the lupus inhibitor was extended by using plasmas filtered through 0.22-micron cellulose acetate filters.

Topics: Blood Coagulation Factors; Blood Coagulation Tests; Cell Separation; Cellulose; Filtration; Humans; Lupus Coagulation Inhibitor; Lupus Erythematosus, Systemic; Partial Thromboplastin Time; Platelet Function Tests; Thromboplastin

Screening tests for circulating anticoagulant were performed systematically in fifteen patients with different stages of syphilis. The lupus-type anticoagulant, an inhibitor of the prothrombin activator complex, was demonstrated in one primary and three secondary stages, without any hemorrhagic complications. The possible relationship between the occurrence of this type of inhibitor and positive antilipoidal tests is discussed in reference to the well-known association of circulating anticoagulant and biologic false positive serologic tests for syphilis observed in patients with SLE.

Topics: Blood Coagulation; Hemostasis; Humans; Immunoglobulins; Lupus Erythematosus, Systemic; Partial Thromboplastin Time; Syphilis; Thromboplastin; Time Factors

Circulating anticoagulants with antiprothrombinase activity were detected in 14 out of 49 patients (i.e. 29%) presenting with severe forms of systemic lupus erythematosus (SLE) predominantly renal (29) or extrarenal (20). Nine of these 14 patients had thrombopenia and 8 had a falsely positive Wassermann test. The anticoagulants were more frequently encountered in patients with severe extrarenal manifestations (9/20 cases) than in patients with severe proliferative renal lesions (5/29 cases). They were found in 5 out of 10 patients with arterial and/or venous thrombosis. Anticoagulant levels paralleled the course of the disease during treatment. No haemorrhage was observed in 14 percutaneous renal biopsies performed on 11 patients free from outer coagulopathies. This suggests that the presence of antiprothrombinase anticoagulants in the blood of patients without thrombopenia or other coagulation disorders is compatible with surgery or biopsy of the kidney.

Topics: Blood Coagulation; Female; Humans; Kidney Diseases; Lupus Erythematosus, Systemic; Male; Thromboplastin; Time Factors; Vascular Diseases

An acquired inhibitor of blood coagulation, similar to that described in patients with Systemic Lupus Erythematosus (SLE), was detected during routine coagulation screening in 10 patients who did not meet the criteria for a diagnosis of SLE. The lupus-like anticoagulant (LLAC) was diagnosed on the basis of prolonged activated partial thromboplastin time (APTT) and/or prothrombin time (PT) which failed to correct when patient plasma was added to normal plasma; an additional criterion was an abnormal tissue thromboplastin inhibition test. No patient had a specific inhibitor directed against factors VIII and IX. Demonstration of LLAC was highly dependent upon the type of reagents adopted in the APTT and PT: the abnormality was detected consistently by one reagent only. One-stage assays of factors VIII and IX were characteristic of the presence of an inhibitor, showing non-parellel dose-response curves or decreased activity at low dilutions which were partially corrected at higher dilutions. Although 7 patients were free of abnormal bleeding, unequivocal signs of haemorrhagic tendency after a surgery were present in the remaining 3 patients. The findings suggest that LLAC is a non-exceptional cause of prolonged coagulation screening tests, and that it may sometimes be associated with impaired haemostasis.

Topics: Adolescent; Adult; Blood Cell Count; Blood Coagulation; Blood Coagulation Factors; Blood Coagulation Tests; Blood Platelets; Child; Diagnosis, Differential; Female; Humans; Lupus Erythematosus, Systemic; Male; Middle Aged; Prothrombin Time; Thromboplastin

Topics: Adult; Aged; Blood Coagulation Factors; Blood Coagulation Tests; Factor XI; Female; Humans; Liver Cirrhosis; Lupus Erythematosus, Systemic; Thromboplastin

Three techniques have been employed for the in vitro detection of circulating platelet antibodies in thrombocytopenic patients affected by 'idiopathic' form or by lupus erythematosus (SLE), the complement fixation test, the platelet factor 3 availability test and the serotonin release test. 29 of the 35 sera tested (82.8%) gave positive results for antiplatelet activity. In particular the serotonin release test allows to distinguish 4 groups of patients: a first group affected by idiopathic form; two groups with autoimmune thrombocytopenia and various degrees of serotonin release, and finally a fourth group which comprises subjects affected by SLE, with circulating immunocomplexes.

Topics: Autoimmune Diseases; Blood Platelets; Chronic Disease; Complement Fixation Tests; Humans; Isoantibodies; Lupus Erythematosus, Systemic; Serotonin; Thrombocytopenia; Thromboplastin

Topics: Adult; Blood Coagulation Tests; Factor VIII; Factor XI; Female; Humans; Immunoglobulin G; Immunoglobulin M; Lupus Erythematosus, Systemic; Male; Middle Aged; Thromboplastin

Eighty-three patients with circulating anticoagulants were studied at The New York Hospital. The lupus-type anticoagulant, an inhibitor of the prothrombin activator complex, was demonstrated in 58 patients. The inhibitor was identified using the blood and tissue thromboplastin inhibition tests. Inhibition by the lupus anticoagulant was augmented in 67% of these patients by a cofactor present in normal plasma. The lupus inhibitor was detected primarily because of an unsuspected abnormal coagulation test. One-half of the patients with the lupus-type anticoagulant did not have systemic lupus erythematosus.

Topics: Anticoagulants; Blood Coagulation Tests; Humans; Lupus Erythematosus, Systemic; Thromboplastin

Plasma from a patient with early manifestations of disseminated lupus erythematosus, a prolonged partial thromboplastin time with kaolin, mildly prolonged prothrombin time, and a circulating inhibitor affecting the assay of several clotting factors was investigated. The most sensitive test for the inhibitor was found to be the Russell viper venom time without phospholipid. A decrease in phospholipid concentration as well as decreased sodium chloride levels both significantly enhanced the effect of the inhibitor in several coagulation tests. Of various phospholipid substitutes tested phosphatidyl ethanolamine was the most effective in partially correcting for the inhibitor. The inhibitor was not localized to the patient's platelets, which were also found to partially neutralize its effect. Since lupus erythematosus is sometimes accompanied by thrombocytopenia the coagulation disorder may be aggravated by such a deficiency of phospholipid. The inhibitor appears to act by preventing binding of phospholipid to the Xa/V/thromboplastin complex. It was characterized as a gamma globulin of mixed class.

Topics: Adult; Blood Coagulation; Blood Coagulation Tests; Blood Platelets; Factor X; Female; Humans; Immunoglobulins; Lupus Erythematosus, Systemic; Phospholipids; Sodium Chloride; Thromboplastin

Topics: Adenosine Diphosphate; Adult; Aged; Antibodies, Anti-Idiotypic; Anticoagulants; Blood Cell Count; Blood Coagulation; Blood Coagulation Tests; Blood Platelets; Chromatography, Gel; Connective Tissue; Epinephrine; Female; Fibrinogen; Hemagglutination Inhibition Tests; Humans; Immunoassay; Immunodiffusion; Immunoelectrophoresis; Immunoglobulin Fragments; Lupus Erythematosus, Systemic; Male; Middle Aged; Platelet Adhesiveness; Platelet Aggregation; Thromboplastin

Topics: Anticoagulants; Blood Coagulation Disorders; Blood Coagulation Factors; Child; Female; Hematuria; Humans; Hypoprothrombinemias; Lupus Erythematosus, Systemic; Prednisone; Prothrombin; Prothrombin Time; Thromboplastin; Vitamin K

Topics: Adult; Aged; Blood Coagulation Disorders; Female; gamma-Globulins; Humans; Immunoelectrophoresis; Lupus Erythematosus, Systemic; Prothrombin; Prothrombin Time; Thrombelastography; Thromboplastin

Topics: Anticoagulants; Blood; Humans; Immunoglobulins; Lupus Erythematosus, Systemic; Thromboplastin

Topics: Anticoagulants; Blood Coagulation Tests; Hemostatics; Humans; Lupus Erythematosus, Systemic; Prothrombin; Thromboplastin

Topics: Anticoagulants; Blood Coagulation Disorders; Humans; Immunoglobulins; Lupus Erythematosus, Systemic; Thromboplastin

Topics: Acquired Immunodeficiency Syndrome; Blood Coagulation Disorders; Humans; Hypersensitivity; Lupus Erythematosus, Systemic; Neutrophils; Prothrombin Time; Thromboplastin

Topics: Adolescent; Anticoagulants; Autoantibodies; Blood Coagulation Disorders; Female; Humans; Immunoglobulins; Lupus Erythematosus, Systemic; Metrorrhagia; Thromboplastin

Topics: Anticoagulants; Autoimmune Diseases; Blood Coagulation Disorders; Collagen Diseases; Humans; Immunoglobulins; Lupus Erythematosus, Systemic; Thromboplastin