Interferon alpha and gamma positive mononuclear cells and HLA antigen expression on hepatocyte membrane in the liver in chronic type B and non-A, non-B hepatitis.

To evaluate the role of local interferon on pathogenesis in chronic type B and non-A, non-B chronic hepatitis, we examined the cellular localization of interferon alpha and gamma, and the expression of HLA antigens in cryostat liver sections from 33 chronic carriers of HBs antigen and 10 patients with non-A, non-B chronic hepatitis, using an immunoperoxidase procedure with monoclonal antibodies. Infiltrating mononuclear cells were the main cell element staining positive for interferon alpha or gamma. Among type B chronic liver disease, the percentages of both interferon alpha- and gamma-positive mononuclear cells were highest in patients with chronic active hepatitis, and their levels were higher in patients who had serum HBe antigen, indicating that local expression of interferon closely correlates with activity of disease and virus replication. On the other hand, both the frequency of interferon alpha or gamma positive cells, and the intensity of HLA class I antigens on hepatocytes were much lower in patients with non-A, non-B, chronic active hepatitis in comparison with those with type B chronic active hepatitis. These findings suggested that locally produced interferons have role of varying degrees on the host defence mechanism in chronic hepatitis, reflecting disease activity and the etiology of the disease.