ABSTRACT

Wegener's granulomatosis (WG) is one of three similar disorders, with microscopic polyangiitis (MPA) and Churg-Strauss syndrome, among the primary small-vessel vasculitides (I). WG is characterized histologically by granulomatous inflammation and vasculitis of the upper and lower respiratory tract and systemic vasculitis with a predilection for the kidneys and lungs. Wegener's granulomatosis usually begins with limited organ involvement (of the upperrespiratory tract) that progresses to systemic disease (generalized WG). Autoantibodies with specificity against the neutrophil cytoplasmic granule enzyme proteinase 3 (PR3-ANCA) are present in virtually all patients with generalized WG and together with presence of circulating T cells which proliferate in vitro, when exposed to PR3, indicate an autoimmune-based pathogenesis. The etiology ofWG remains unknown, but in the past 15 years, many processes that may sustain and amplify the disease have been identified.