Clinical significance of ANCA in 98 patients.

Clinical and histological data leading to precise diagnosis were retrospectively obtained in 98 patients with antineutrophil cytoplasmic antibodies (ANCA) detected by indirect immunofluorescence (IIF). Specificity was determined by myeloperoxidase (MPO) and proteinase 3 (PR3) specific ELISA in all and a comparative study based on ANCA specificity was performed. Vasculitis was present in all cases. PR3-ANCA occurred predominantly in males (25/38) with WG (19/38). MPO-ANCA occurred predominantly in older women and were often associated with various autoimmune disorders. There was a high prevalence of lung hemorrhage (18/45) and mPA (26/45) in this group. Patients with negative MPO and PR3 specific ELISA despite positive IIF (n = 15) were almost exclusively WG (13/15) and were characterized by a high prevalence of hepatic and digestive manifestations. Renal and patient survival at the 75th percentile was 15 months with MPO-ANCA and 16 months with PR3, and was similar for patients with WG and mPA. With immunosuppressive treatment, ANCA disappeared in 66% of cases and this disappearance was always associated with absence of disease activity.