Pathogenesis of lung vasculitis.

Vasculitides that affect the lung represent a diverse group of diseases with various systemic clinical manifestations, and include microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA, formerly Wegener granulomatosis), Churg-Strauss syndrome (CSS), and anti-glomerular basement membrane (anti-GBM) disease (Goodpasture syndrome). The etiologies of these diseases remain largely unknown. Although the pathogenic mechanisms of each differ, these diseases overlap by the presence of anti-neutrophil cytoplasmic autoantibodies in the vast majority of patients with MPA and GPA, and a substantial minority of patients with CSS and anti-GBM disease. This article reviews the current understanding of the pathogenesis of these four disease entities.