Primary biliary cirrhosis (PBC) is a chronic cholestatic progressive liver disease frequently associated with various immunological abnormalities. We have studied the influence of normal and PBC adherent cells (AC) on peripheral blood lymphocytes (PBL) colony growth both in liquid and soft agar culture. Co-culture experiments with different combinations of AC and PBL of PBC patients and normal donors provided evidence that PBC adherent cells function abnormally. However, this impaired function is not the sole factor involved, since the number of colonies formed by PBC lymphocytes in the presence of normal AC was twice the normal value. The possibility that this increase is correlated with the state of activation of T cells is discussed in the light of the high number of DR-positive T cells found in the PBC patients studied. Finally, none of these immunological abnormalities was related to the stage of the disease.