[Antineutrophilic cytoplasmic antibodies (ANCA) in inflammatory rheumatic diseases: immunodiagnostic and immunopathogenetic aspects].

Anti-neutrophil cytoplasmic antibodies (ANCA) are a heterogeneous group of autoantibodies with a wide and diverse range of clinical associations. Over the past decade ANCA have been the subject of extensive investigations. In vasculitis the diagnostic utility of proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA for Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA), respectively, is now well established. Because of their significance as tools for diagnosis and prognosis of "ANCA-associated vasculitides," these autoantibodies have been analyzed extensively as markers for underlying immunopathogenic disturbances. Data regarding the detection of ANCA and their diagnostic value and role in the pathogenesis of rheumatic disorders will be discussed in this review. Growing evidence points to a pathophysiologic and diagnostic relevance of the ANCA target antigens PR3 and MPO. To date, there is mounting evidence that ANCA can have pathophysiologic effects on neutrophils, and may play a direct role in ANCA-associated vasculitides. A pathogenic model for ANCA-mediated vasculitis will be presented in this paper.