Aims: This retrospective study defined the clinical features and outcome of antineutrophil cytoplasmic antibody- associated glomerulonephritis in 18 seropositive Taiwanese patients (11 male, seven female; median age 64 years; range 21-82 years) with biopsy-proven pauci-immune necrotizing crescentic glomerulonephritis. Results: Fourteen patients had a diagnosis of systemic vasculitis including 10 with microscopic polyangiitis and four with Wegener's granulomatosis; the remaining four had only glomerulonephritis. At onset, 100% of the systemic vasculitis patients had pulmonary lesions with or without haemoptysis, and 29% presented with seizure in the absence of a defined brain lesion. Median serum creatinine concentration was 362.4 mumol/L (range 61.9-857.5 mumol/L) and dialysis therapy was needed in six patients. During follow up (median 16.5 months; range 2-72 months), treatment included cyclophosphamide and corticosteroids (n = 8) or corticosteroids alone (n = 7). In some patients , treatment improved (n = 4) or stabilized (n = 4) renal function. But chronic dialysis was needed in the other 10 patients. Follow -up death occurred because of sepsis (n = 3) and haemorrhage (n = 2). Patient survival rates were 78% (1 year) and 72% ( 5 years). Renal survival rates were 56 and 39% at 1 and 5 years, respectively. Of the candidate clinical and pathological parameters, chronic glomerular lesions in renal biopsy were the only determinant of poor renal outcome (P = 0.006). Conclusion: Antineutrophil cytoplasmic antibody- associated glomerulonephritis should be considered in nephritic patients with extrarenal manifestations, especially pulmonary infiltrate, unexplained seizure, and fever of an unknown origin in Taiwanese patients. Renal biopsy should be performed before initiating immunosuppressive therapy because the most common cause of mortality was sepsis
