ANCA were detected in 67% of sera from patients with primary sclerosing cholangitis (n = 15), in 83% of sera from patients with autoimmune chronic active hepatitis (n = 18) and in 35% of sera from patients with primary biliary cirrhosis (n = 20). ANCA were not detected in non-autoimmune chronic liver diseases. Characterization studies of the antigens involved showed that ANCA in autoimmune liver disease are not directed against myeloperoxidase (mpo), proteinase 3 (pr3) or elastase (hle), but the ANCA in autoimmune liver disease show reactivity with lactoferrin, a 67/66 kD protein combination or a 63/54 kD protein combination on Western Blots.