[Special features of ANCA-associated vasculitides].

SPECIAL FEATURES OF ANCA-ASSOCIATED VASCULITIDES. Necrotizing vasculitis associated to antineutrophil cytoplasmic antibodies (ANCA) are one of the subgroups of vasculitis affecting small-sized vessels. Fibrinoid necrosis of the vascular wall is present. Two antibodies have been identified: anti-proteinase 3 which is mainly found in granulomatosis with polyangiitis, and anti-myeloperoxydase which is mainly observed in eosinophilic granulomatosis with polyangiitis and microscopic polyangiitis. Flares are frequent. Spontaneous prognosis is poor. The three diseases of the group are granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis and microscopic polyangiitis. When treatments are prescribed, outcomes and long term evolution are good but relapses are frequent.