cathepsin-g and Cholangitis--Sclerosing

Anti-neutrophil cytoplasmic antibodies (ANCA) against proteinase 3 are diagnostic of Wegener's granulomatosis, but ANCA occur also in patients with other inflammatory disorders, such as ulcerative colitis, primary sclerosing cholangitis (PSC) and autoimmune hepatitis. As their predictive value for autoimmune liver disease remains unknown, we analysed the prevalence and antigen specificity of ANCA in patients with various chronic liver diseases (CLD).. We studied sera from 100 patients with primary biliary cirrhosis (PBC), from 76 with PSC and from 279 with various CLD, consecutively drawn during a 5-year period at the time of liver biopsy. The ANCA were detected by indirect immunofluorescence (IIF) while the antigen specificity was characterized by ELISA by using lactoferrin, neutrophil elastase, cathepsin G and BPI (bactericidal/permeability increasing protein) as antigens.. In PBC, ANCA were detected by IIF in 39 patients (39%). The antigen reactivity by ELISA was lactoferrin in seven, elastase in 15, BPI in 20 and cathepsin G in four patients. Four patients had reactivity against more than one antigen. In PSC, IIF demonstrated ANCA in 49 patients (65%). The antigen reactivity was lactoferrin in 17, elastase in 14, BPI in 20 and cathepsin G in four patients. Twelve patients showed reactivity against more than one antigen. In CLD, ANCA were observed in sera from 55 patients (20%). Nineteen of 45 patients (42%) with autoimmune liver disease were ANCA positive versus 36/234 (15%) with non-autoimmune liver disease (P = 0.0002). Among IIF-positive patients, antibody reactivity against lactoferrin was noted in 14, elastase in 28, BPI in 25 and cathepsin G in five patients. Twenty-one patients had reactivity against more than one antigen. Elastase and BPI antibodies occurred more frequently in patients with autoimmune compared to non-autoimmune liver disease (P < 0.01).. Anti-neutrophil cytoplasmic antibodies are prevalent in patients with chronic liver diseases, but although they occur more frequently in patients with autoimmune liver disease their specificity and sensitivity for autoimmune liver disease is low. The predominant antigens are lactoferrin, elastase and BPI, but the correlation between IIF findings and ELISA reactivity against these antigens is weak.

Topics: Antibodies, Antineutrophil Cytoplasmic; Antimicrobial Cationic Peptides; Autoantigens; Biomarkers; Blood Proteins; Cathepsin G; Cathepsins; Cholangitis, Sclerosing; Enzyme-Linked Immunosorbent Assay; Epitopes; Fluorescent Antibody Technique, Indirect; Hepatitis, Autoimmune; Humans; Lactoferrin; Leukocyte Elastase; Liver Cirrhosis, Biliary; Membrane Proteins; Myeloblastin; Prognosis; Sensitivity and Specificity; Serine Endopeptidases

To characterize the antigen specificity of circulating anti-neutrophil cytoplasmic antibodies (ANCAs) in inflammatory bowel disease (IBD).. Analysis of the prevalence of circulating ANCAs in patients with ulcerative colitis and Crohn's disease, by both non-specific methods (immunofluorescence against fixed neutrophil leukocytes) and specific antigen techniques (against purified neutrophil leukocyte constituents).. Indirect immunofluorescence against fixed polymorphonuclear leukocytes, and solid-phase enzyme-linked immunosorbent assay (ELISA) against neutrophil constituents (alpha-granules, elastase, myeloperoxidase, cathepsin g, lysozyme and lactoferrin).. Although results using immunofluorescence were typical of other studies (ulcerative colitis positive in 41%, Crohn's disease in 10%), ELISA studies showed antibody activity against neutrophil components in 69% of patients with ulcerative colitis and 39% of those with Crohn's disease. Antibodies in ulcerative colitis were commonly directed (in descending order) against lysozyme, cathepsin G, elastase, and lactoferrin, and in Crohn's disease against lysozyme.. Correlation of indirect immunofluorescence data and ELISA results indicated that even this large panel of specific antigens fails to identify all the ANCA targets in IBD. The lack of correlation between the findings of ANCAs, either in general or versus a specific target, and disease extent or activity in ulcerative colitis supports the suggestion that ANCAs are unlikely to be of primary importance in pathogenesis.

Topics: Adult; Aged; Antibodies; Antibodies, Antineutrophil Cytoplasmic; Autoantibodies; Cathepsin G; Cathepsins; Cholangitis, Sclerosing; Colitis, Ulcerative; Crohn Disease; Cytoplasmic Granules; Enzyme-Linked Immunosorbent Assay; Epitopes; Female; Fluorescent Antibody Technique, Indirect; Humans; Immunoglobulin G; Inflammatory Bowel Diseases; Lactoferrin; Leukocyte Elastase; Male; Middle Aged; Muramidase; Neutrophils; Pancreatic Elastase; Peroxidase; Serine Endopeptidases; Vasculitis

Primary sclerosing cholangitis (PSC) is a chronic progressive liver disease of unknown etiology. It has been suggested that genetic and immunological factors are important in its pathogenesis. The present study examined the prevalence of 23 different autoantibodies in 25 PSC sera, by ELISA, in order to better define the autoimmune profile of PSC. The results indicate that 88% of PSC patients produced at least 1 autoantibody, and 36% had reactivity to multiple autoantibodies. Moreover, 35% of the PSC patients produced anti-endothelial-cell antibodies (AECA) and 75% of the sera contained perinuclear antineutrophil cytoplasmic antibodies (pANCA), detected by indirect immunofluorescence. The prominent ANCA autoantibody was anti-cathepsin-G, demonstrated in 35% of the patients. The multiplicity of the autoantibody profile, revealed in the present study, points to the autoimmune characteristics of PSC. In addition, the association of ANCA and of AECA in PSC may suggest a pathogenic role for these antibodies in PSC.

Topics: Antibodies, Antineutrophil Cytoplasmic; Antibodies, Antinuclear; Autoantibodies; Autoimmune Diseases; Biomarkers; Cathepsin G; Cathepsins; Cholangitis, Sclerosing; Fluorescent Antibody Technique, Indirect; Humans; Serine Endopeptidases

Autoantibodies directed against polymorphonuclear neutrophils (PMN) have been observed in serum from patients with ulcerative colitis (UC), Crohn's disease (CD) and primary sclerosing cholangitis (PSC) using indirect immunofluorescence and fixed granulocyte ELISA. Our study demonstrates the presence in the serum of these patients of autoantibodies which bind to an azurophilic granule component distinct from proteinase 3, elastase and myeloperoxidase. These autoantibodies thus belong to the ANCA family, but their antigen specificity differs from the already characterized ANCA antigens. We have found that the same ANCA antigen target, named UC-antigen, was recognized by serum IgG from patients with UC, CD and PSC. It was purified by Matrex Gel Orange A dye affinity chromatography and subsequent immunoabsorption of contaminant proteinase 3 with immobilized anti-proteinase 3 MoAb. The identity between this UC antigen and cathepsin G was demonstrated by their coelution from Matrex Gel Orange A column and the parallel titration of cathepsin G-specific enzymatic activity and UC-ANCA binding, both in partially purified UC antigen and in highly pure cathepsin G. Furthermore, the use of cathepsin G ELISA confirmed that UC, CD and PSC patients' IgG did indeed bind to cathepsin G. Comparison of the results obtained with azurophilic granule- and cathepsin G-ELISA as well as inhibition of ANCA binding by anti-cathepsin G polyclonal antibodies, revealed that in some patients cathepsin G is the main azurophilic granule target of ANCA while others have other ANCA specificities. The fact that UC, CD and PSC are frequently associated with cathepsin G ANCA, while rarely occurring in other types of vasculitis, is intriguing but suggests that these diseases may have a common pathogenetic mechanism.

Topics: Autoantibodies; Cathepsin G; Cathepsins; Cholangitis, Sclerosing; Colitis, Ulcerative; Crohn Disease; Cytoplasmic Granules; Humans; Lactoferrin; Myeloblastin; Neutrophils; Pancreatic Elastase; Peroxidase; Serine Endopeptidases