High-dose, pooled, i.v. immunoglobulin (IVIg) is a potential, alternative treatment for Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA) which has shown promise in the treatment of refractory disease when administered with continuing immunosuppression. This study of six new patients with antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis and early disease, without threatened vital organ function, examined the therapeutic response to treatment with IVIg alone. IVIg was well tolerated and all six patients had early reductions in disease activity. Four entered full, clinical remission which lasted for at least 1 yr, while in two the responses were partial and transient, and they subsequently required conventional treatment. After 16-48 months of follow-up, two of the four patients in full remission relapsed, but the other two have remained well.