Renal disease associated with circulating antineutrophil cytoplasm activity.
We report our detailed observations on a group of 30 consecutive patients with renal disease, histologically demonstrated glomerulitis or necrotizing vasculitis, and circulating antineutrophil cytoplasm activity (ANCA). The annual incidence of ANCA-related renal disease was seven cases per million population. The sensitivity of serum ANCA for histologically proved glomerular vasculitis was 79 per cent, with a specificity of 87 per cent. Most patients responded to treatment with cyclophosphamide and steroids but complications of therapy occurred in just over half the patients and were serious in 20 per cent. Actuarial survival at 1 year was 60 per cent. Age and dialysis requirement did not influence outcome and the only identified adverse prognostic factor was hypoxic lung disease. We conclude that the association of ANCA with renal disease is not rare and that positive serology accurately identifies a homogeneous group of patients with similar clinical, histological, and prognostic features. Separation of these patients into those with the disease entities of Wegener's granulomatosis and microscopic polyarteritis is not straightforward on clinical and histological criteria, and such a distinction does not yield useful therapeutic or prognostic information. Simple urinalysis should always be carried out in patients with undiagnosed systemic illness in order to identify renal disease. ANCA-related renal disease can be treated successfully with cyclophosphamide and steroids and elderly patients should not be excluded from treatment, including dialysis if necessary. The ANCA test is simple and quick to perform and, in the appropriate clinical setting, accurately identifies patients who may benefit from immunosuppressive treatment before a histological diagnosis can be established.