cathepsin-g and Liver-Diseases

Atypical antineutrophil cytoplasm antibodies (A-ANCA) are defined here as ANCA detected by IIF and not directed against the predominant ANCA antigens, proteinase 3 (PR3) and myeloperoxidase (MPO). A-ANCA are found in a variety of clinical conditions, namely rheumatoid arthritis, inflammatory bowel diseases, chronic hepatic diseases and several infections including HIV infection. They are directed against a variety of still ill-defined neutrophil antigens and most frequently yield a perinuclear pattern (P-ANCA) of binding by indirect immunofluorescence on ethanol fixed neutrophils. This paper reviews the literature on A-ANCA and our recent data suggesting that, among others, cathepsin G is one of the predominant antigen targets of A-ANCA. From a clinical point of view, the distinction between MPO-ANCA and A-ANCA is not possible by indirect immunofluorescence (IIF). The determination of ANCA antigens by specific ELISA is therefore necessary to differentiate P-ANCA with MPO specificity from those with undefined specificity. This is of importance because the clinical value of MPO-ANCA is clearly established while the presence of A-ANCA is difficult to interpret given their occurrence in a large variety of clinical conditions.

Topics: Antibodies, Antineutrophil Cytoplasmic; Antibody Specificity; Arthritis, Rheumatoid; Autoantibodies; Autoantigens; Autoimmune Diseases; Cathepsin G; Cathepsins; Cytoplasm; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Humans; Infections; Inflammatory Bowel Diseases; Liver Diseases; Myeloblastin; Neutrophils; Pancreatic Elastase; Peroxidase; Serine Endopeptidases

Sera from 35 out of 655 patients with suspected or confirmed hepatobiliary diseases were positive for anti-neutrophil antibodies with a perinuclear staining pattern (p-ANCA). Nineteen of these sera did not react with myeloperoxidase (MPO), Cathepsin G or Elastase, the three proposed antigens of p-ANCAs. No distinct antigen for these sera could be characterized by western blot techniques with fractionated granulocyte proteins.

Topics: Antibodies, Antineutrophil Cytoplasmic; Antibody Specificity; Autoantibodies; Biliary Tract Diseases; Blotting, Western; Cathepsin G; Cathepsins; Humans; Immunoglobulin G; Liver Diseases; Pancreatic Elastase; Peroxidase; Serine Endopeptidases