Role in the Pathogenesis of Vasculitis

Antineutrophil cy to plas mic an ti bod ies (ANCA) are a het er o ge neous group of cir cu lat ing an ti bod ies di rected to ward the cy to plas mic con stit u ents of neutrophil gran ules and monocytes. ANCA were first de scribed in 1982 by Davies et al. in a few pa tients with seg men tal necrotizing glomerulone phritis (1,2). The im por tance of this ob ser va tion had not been rec og nized un til 1985, when a dis tinct gran u lar cy to plas mic flu o res cence pat tern, first called ACPA (anticytoplasmic an ti bod ies) and later termed C-ANCA (cy to plas mic), was shown to be as so ci ated with Wegener¢s granulomatosis (WG) (3). Later, a sec ond ANCA flu o res cence pat tern (later called perinuclear, P-ANCA) was de scribed in pa tients with mi cro scopic polyangiitis (MPA) (4) and in pa tients with the id io pathic form of pauci-im mune necrotizing cres cen tic glomerulonephritis (iNCGN) (5). These data have now been con firmed by many groups and sup port the view that ANCA-as so ci ated vasculitis and glomerulonephritis are in deed a dis tinct dis ease cat e gory (6-11). Sub se quently, a third, less clearcut ANCA sub type (later termed ‘atyp i cal’ or very perinuclear, a/P-ANCA) was de scribed in a wide range of con nec tive tis sue dis eases (CTD), inflammatory bowel (IBD) and autoimmune liver diseases, and infectious diseases (8-13).