Recent evidence has suggested that peripheral blood suppressor cell populations can modulate immune responsiveness. Absence of suppressor cell activity has been noted in diseases of presumed autoimmune basis. We determined inducible suppressor cell activity in patients with primary biliary cirrhosis (PBC) as compared to age and sex-matched controls. There was a significant loss of suppressor cell activity for mitogen response in patients with PBC (-4.5 +/- 8.0%) versus controls (43.7 +/- 7.8%). No correlation of this loss to clinical parameters was observed. This study suggests PBC patients lack inducible suppressor cell activity provide partial explanation for the perpetuation of this disease.