[Anti-neutrophil cytoplasmic autoantibody (ANCA) in systemic vasculitic syndrome]

Anti-neutrophil cytoplasmic autoantibodies (ANCA) specific for constituents of neutrophil primary granules were used for enzyme immunosorbent assay in patients with vasculitic syndrome and glomerulonephritis. Proteinase 3 specific ANCA (PR3-ANCA), which include most of cytoplasmic staining pattern ANCA on indirect immunofluorescence assay (IIF) using alcohol-fixed neutrophils, were useful serologic markers for diagnosis of Wegener's granulomatosis and their titers correlated with disease activity. Myeloperoxidase specific ANCA (MPO-ANCA), which include most of perinuclear staining pattern ANCA on IIF, were detected not only in patients with well recognized clinicopathologic vasculitic syndrome and glomerulonephritis, such as microscopic polyarteritis nodosa, allergic granulomatous angitis and idiopathic crescentic necrotizing glomerulonephritis but were also detected in patients with unclassified vasculitis which are difficult to assign to a distinct diagnostic category. Patients with MPO-ANCA had common clinicopathological features, such as rapidly progressive glomerulonephritic syndrome, pulmonary hemorrhage and purpura. Histologically, patients with MPO-ANCA had focal segmental necrotizing glomerulonephritis with various degrees of crescent, pulmonary alveolar hemorrhage and leukocytoclastic vasculitis induced by necrotizing capillaries. A new clinical entity, MPO-ANCA related vasculitis in vasculitic syndrome, is proposed to manage and investigate the pathogenesis of vasculitis.