Investigation into the therapeutic use of intravenous immunoglobulin (IVIg) in systemic vasculitis was prompted by the detection of anti-idiotype antibodies reactive with ANCA in IVIg and the proven ability of IVIg to reduce the incidence of coronary artery aneurysms in Kawasaki disease. The efficacy and safety of IVIg (Sandoglobulin) was assessed in an open study of 26 patients with active systemic vasculitis. Eight weeks after IVIg 13 patients were in full and 13 in partial remission, clinical benefit was maintained in 18 twelve months later and was reflected by changes in C-reactive protein and ANCA.