PERIPHERAL B-LYMPHOCYTE REPERTOIRE TO MITOCHONDRIAL ANTIGEN IN PRIMARY BILIARY-CIRRHOSIS - POSITIVE CORRELATION BETWEEN THE DISEASE-ACTIVITY AND THE FREQUENCY OF CIRCULATING B-LYMPHOCYTES SPECIFIC FOR PYRUVATEDEHYDROGE NASE COMPLEX

B lymphocytes committed to the production of IgG antibodies (Abs) to m itochondrial antigen such as pyruvate dehydrogenase complex(PDC) were quantitated in the peripheral blood of patients with primary biliary c irrhosis(PBC) using Epstein-Barr virus as a polyclonal activator of hu man B lymphocytes. B lymphocytes committed to the production of IgG Ab s to PDC were found in high frequency in patients with PBC(0.54 +/- 0. 16%, mean value +/- SE, of total IgG-producing B lymphocytes) in contr ast to type C chronic hepatitis and healthy subjects in which they wer e less than 0.01%. The frequency of these B lymphocytes specific for P DC increased in parallel to the progression of the Scheuer's stage fro m I to II(stage I:0.35 +/- 0.23%, stage II:1.04 +/- 0.32%), but decrea sed with further progression to stage IV(stage III:0.39 +/- 0.21%, sta geIV:0.07 +/- 0.06%). In addition, B lymphocytes specific for PDC decr eased in the peripheral blood during the administration of cyclosporin A; this was accompanied by an improvement of lymphocyte infiltration severity in the liver. These data indicate that B lymphocytes specific for PDC are present in the peripheral blood of patients with PBC and their frequency reflects the degree of the lymphocyte infiltration in the liver.