Hepatic beta 2-microglobulin distribution in primary biliary cirrhosis.

The distribution of beta 2-microglobulin (beta 2-m) was studied by immunoperoxidase in paraffin sections of 30 liver biopsies from 28 patients with primary biliary cirrhosis (PBC). In 24 of the patients beta 2-m was demonstrable on the membranes of hepatocytes, whereas normal hepatocytes were usually negative. This increased display of beta 2-m probably parallels increased display of class I HLA antigens. The affected hepatocytes may be more susceptible to T cell-mediated immune attack. A greater number of beta 2-m displaying hepatocytes was seen in the later stages of PBC, in keeping with the hypothesis that in this disease hepatocyte involvement is a secondary phenomenon. Bile duct epithelium continued to display beta 2-m at all stages of the disease.