Expression of β 2 −microglobulin on hepatocytes in acute and chronic type B hepatitis

β 2 −Microglobulin display was examined in 131 liver biopsies from patients with acute and chronic type B hepatitis, using an indirect immunoperoxidase method. Enhanced expression of β 2 −microglobulin on hepatocyte membranes was observed in patients with acute hepatitis, chronic active hepatitis with moderate to severe activity and cirrhosis, when compared with normal liver. In acute hepatitis, β 2 −microglobulin‐positive hepatocytes were mainly observed in perivenular areas in association with bridging necrosis. In chronic hepatitis, β 2 −microglobulin‐positive hepatocytes were observed mainly in periportal zones and in some areas of lobular activty. Diffuse‐enhanced display of β 2 −microglobulin on hepatocytes was observed in 5 of 6 patients treated with lymphoblastoid interferon as part of a trial of antiviral therapy. The mechanism by which β 2 −microglobulin display is enhanced on hepatocytes in patients not treated with interferon is uncertain. However, display of β 2 −microglobulin on hepatocytes probably reflects display of HLA‐A, B and C antigens and may influence the course of hepatitis B virus infection by increasing susceptibility of the affectedcells to T cell‐mediated immune attack.