Autoantibodies to isolated human hepatocyte plasma membranes in liver disease: I. Specificity for chronic active hepatitis

Abstract Circulating autoantibodies reacting with human hepatocyte plasma membranes (HHPM) were quantitated in acute and chronic liver disease using an enzyme-linked immunosorbent assay (ELISA). Anti-HHPM were found most frequently in patients with chronic active hepatitis (CAH), a disease postulated to result from autoimmune processes directed at organ-specific antigens on the surface of hepatocytes. The high incidence of anti-HHPM in CAH (75%) contrasted significantly with all other groups assayed, including primary biliary cirrhosis (44%), alcoholic liver disease (21%), acute viral hepatitis (17%), and chronic persistent hepatitis (8%). The titers of anti-HHPM in CAH were significantly greater than in other liver disease and control groups. Anti-HHPM quantitated by ELISA correlated with hepatocellular membrane staining by indirect immunofluorescence. Autoantibodies to HHPM were found with an equivalent frequency in three etiological subgroups of CAH: autoimmune CAH, hepatitis B virus (HBV)-related CAH, and CAH associated with excess alcohol consumption. Anti-HHPM of the IgG and IgA isotypes were found in the highest frequency. There was a trend for patients with a histologically more severe disease to have higher titers of anti-HHPM. Immunoblots of SDS-PAGE-separated HHPM showed antibodies to react with a number of polypeptides, some of which appeared human specific. These data suggest that isolated HHPM are a source of relevant hepatocellular membrane antigens. Further studies of the different antigenic specificities of anti-HHPM are required to define which of these may be of pathogenetic importance in chronic active hepatitis.