No abstract

This prospective study was designed to determine the role of antineutrophil cytoplasmic autoantibodies (ANCA) in HIV-infected patients. Immunofluorescence tests (IFT) and enzyme-linked immunosorbent assays (ELISA) were applied to sera of 199 consecutive outpatients. In the IFT 20% were positive. An atypical ANCA pattern was demonstrated in 67% of these, 33% revealed a perinuclear staining (pANCA). Specific ELISA revealed proteinase 3 (n = 2), myeloperoxidase (n = 1), lysozyme (n = 2), lactoferrin (n = 1), cathepsin G (n = 1), and human leukocyte elastase (HLE, n = 6). The target antigen remained unidentified in 26 patients. Perinuclear ANCA-positive patients showed atypical antigens in eight of 13 cases; all six patients with anti-HLE revealed a pANCA pattern. The antigens of atypical ANCA-positive patients remained unidentified in 21 of 26 (81%) cases. No signs of vasculitis were present in the ANCA-positive patients. ANCA are frequently found in the sera of HIV-positive patients. They bind to a variety of antigens. No correlation was found between ANCA positivity and autoimmune or opportunistic diseases.

No abstract

Anti-neutrophil cytoplasmic antibodies (ANCA) are a system of autoantibodies which are strongly associated with the primary systemic vasculitides (PSV). cANCA, as detected by indirect immunofluorescence, are mostly reactive to pro-teinase 3 (PR3) and bear high sensitivity and specificity for Wegener’s granulomatosis. pANCA have varied subspecificities and clinical associations. The most important subspecificity of pANCA is anti-myeloperoxidase (MPO), which is strongly associated with microscopic polyaniitis and pauci-immune crescentic glomerulonephritis. pANCA also occur at low to moderate frequency in other PSV, collagen vascular disease, inflammatory bowel disease and autoimmune liver disease. In systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), pANCA of varied subspecificity have been found, including anti-MPO at low rate and low titer, while cANCA and anti-PR3 were generally absent. Consequently, anti-PR3 (PR3-ANCA) and anti-MPO (MPO-ANCA) at moderate and high titer are distinguishing features of the PSV and, in an appropriate clinical setting, argue strongly against the presence of SLE or RA. Since no significant clinical association has been found for other pANCA subspecificities, cANCA, PR3-ANCA and MPO-ANCA remain the critical elements of ANCA testing in the clinical diagnosis of generalized autoimmune diseases.