HEPATIC HLA-ANTIGEN DISPLAY IN CHRONIC HEPATITIS-B VIRUS-INFECTION - RELATION TO HEPATIC EXPRESSION OF HBV GENOME GENE-PRODUCTS AND LIVER HISTOLOGY

To determine the relationship between hepatitis B virus (HBV) replication and HLA antigen display at a cellular level, the hepatic expression of HLA antigens and HBV genome (HBV-DNA)/gene products (HB(s)4g/HB(c)Ag) was studied in 24 patients with chronic HBV infection using simultaneously immunohistochemistry and nonisotopic in situ hybridization. The effect of interferon-alpha and interferon-gamma on hepatocyte HLA antigen expression was also evaluated using primary hepatocyte culture in eight patients with chronic HBV infection. HLA class I antigens were detected on hepatocyte membrane in 23 patients (95.8%). Hepatocytes positive for HB(c)Ag and HBV-DNA (cytoplasmic +/-nuclear) were either negative or only faintly positive for HLA class I antigens, while hepatocytes positive for HB(s)Ag showed similar levels of HLA class I antigen expression compared with those hepatocytes with no HB(s)Ag expression. In contrast, hepatocytes adjacent to inflammatory infiltrates, whether positive for HBV-DNA or HBV antigens or not, were always strongly positive for HLA class I antigens. Furthermore, active liver histology (N = 12) was associated with a higher overall level of hepatic HLA class I antigen expression as compared with inactive histology (N = 12, P = 0.003). Both interferon-alpha and interferon-gamma treatment in vitro enhanced hepatocyte HLA class I antigen expression. These data indicate that expression of HLA class I antigens is not enhanced on the membrane of hepatocytes with HBV replication, and this may be one factor that permits the development of viral persistence.