Granulomatosis with polyangiitis and microscopic polyangiitis: pathogenesis and clinical manifestations

This literature review addresses the epidemiology, genetic markers, pathogenesis, clinical features, and diagnostic approaches of granulomatosis with polyangiitis and microscopic polyangiitis – both antineutrophil cytoplasmic antibody-associated vasculitides. Particular attention is paid to the role of neutrophil activation and the alternative complement pathway in disease development. The review also includes information on avacopan, an orally administered, selective C5a receptor (C5aR1) inhibitor that blocks the C5a complement component signaling pathway.