Sequential development of systemic vasculitis with anti-neutrophil cytoplasmic antibodies complicating anti-glomerular basement membrane disease.

Anti-neutrophil cytoplasmic antibodies (cANCA) were detected in 3 patients with anti-glomerular basement membrane (anti-GBM) disease. All 3 cases presented late in their clinical course, with severe renal involvement and alveolar hemorrhage. Anti-neutrophil cytoplasmic antibodies were associated with clinical features outwith the lungs and kidneys; in one case cANCA were initially absent but subsequently developed concurrently with the clinical appearance of systemic vasculitis as the anti-GBM antibody titer was falling. These findings confirm that cANCA can complicate anti-GBM disease and suggest that cANCA may identify a distinct subset of patients with anti-GBM disease, supporting a pathogenic role for cANCA in the development of systemic vasculitis.