Effects of interferon on intrahepatic human leukocyte antigens and lymphocyte subsets in patients with chronic hepatitis B and C.

We investigated the effects of interferon therapy on hepatocyte human leukocyte antigen class I and class II antigen expression and intrahepatic lymphocyte subsets in patients with chronic viral hepatitis B (n = 11) and C (n = 10). Interferon-alpha was administered intramuscularly in doses ranging from 3 to 18 million international units daily for 4 wk. Liver biopsy specimens were obtained just before and immediately after treatment, and the specimens were stained by the indirect immunoperoxidase method for evaluation of human leukocyte antigen expression and lymphocyte subsets. Before therapy, no significant difference was noted between hepatitis B and C in human leukocyte antigen class I antigen expression on hepatocytes or in the lymphocyte subsets in the intralobular and portal areas. After interferon-alpha treatment, hepatocyte expression of human leukocyte antigen class I antigens and serum beta 2-microglobulin levels were virtually unchanged in chronic viral hepatitis C patients, but both were increased in chronic viral hepatitis B patients. Human leukocyte antigen class II antigens were not expressed during treatment. The mean number of intralobular CD3+ and CD8+ cells and the mean serum ALT level decreased significantly in chronic viral hepatitis C patients (p less than 0.05) but not in chronic viral hepatitis B patients. The mean number of intralobular CD4+ cells was unaffected by interferon therapy in both groups. In all 21 patients, the changes in CD8+ cell numbers paralleled the changes in serum ALT levels. Our findings suggest that T-cell cytotoxicity may play an important role in hepatocyte damage in both chronic viral hepatitis C and chronic viral hepatitis B and that the response to interferon-alpha differs in these two types of hepatitis.