Renal disease associated with antineutrophil cytoplasmic antibody: 39 patients over a 5-year period

We have reviewed 39 adult patients who presented over a 5-year period with biopsy confirmed renal disease in association with positive antineutrophil cytoplasmic antibody (18 with C-ANCA, 21 with P-ANCA). Twenty-three (59%) had primary systemic vasculitis, typically with aggressive renal histology including focal necrotising and crescentic glomerulonephritis. In the remaining patients a wide range of clinical syndromes and renal histological appearances were apparent: 30 had abnormal renal function (serum creatinine > 140 mumol/l), including 17 who were initially dialysis-dependent. Intensive immunosuppression was administered in 33 cases. When response was assessed at 3 months, renal function was stable or improved in 17 (52%), 5 of whom were able to discontinue dialysis. There was, however, an appreciable early mortality and, at latest follow-up (1-57 months), 12 patients had died and 8 were on the dialysis programme. On immunosuppression, ANCA became negative in the majority (median time 1.5 months) but recurred during clinical relapse in 11 cases. In asymptomatic patients (12 cases), the reappearance of ANCA positivity did not herald clinical relapse. The ANCA assay has increased awareness of systemic vasculitis but not removed the need for histological confirmation before instituting immunosuppression.