Diagnostic and pathogenetic role of antineutrophil cytoplasmic autoantibodies

Anti-neutrophil cytoplasmic antibodies (ANCA) are mostly known as a useful diagnostic tool in patients with small-vessel vasculitides. With the accumulating knowledge of these autoantibodies, however, it becomes clear that the role of ANCA may not be only limited to a diagnosis of such disorders. The current review addresses, in addition to classical diagnostic associations, other diseases connected with ANCA positivity, both in adults and in children. The etiology of ANCA remains unknown, but still, the importance of both genetic and environmental factors is undoubted. The role of infection and chemicals in the etiology of ANCA-associated diseases is stressed in particular. A pathogenetic role of ANCA is suggested because of clinical observations based on the correlation of the vasculitis activity and the titer of ANCA. Many experiments show the effects of ANCA in various steps of an inflammatory process, particularly on leukocyte microbicidal activity and oxidative burst. Recent findings are analyzed in the experimental field and they are correlated with clinical significance.