Hepatocellular and biliary expression of HLA antigens in primary biliary cirrhosis before and after ursodeoxycholic acid therapy.

Recently, there have been reports that ursodeoxycholic acid (UDCA) therapy has a beneficial effect on liver function in patients with primary biliary cirrhosis. However, information regarding the effects of UDCA therapy on hepatic histology remains insufficient. Aberrant expression of HLA antigens on hepatocytes is regarded important in the progression of hepatocellular damages mediated by cytotoxic T-cells in primary biliary cirrhosis. In this study, we examined immunohistochemically hepatocellular expression of HLA antigens on hepatocytes before and after UDCA therapy in four patients with asymptomatic primary biliary cirrhosis. Piecemeal necrosis, intralobular focal necrosis, and portal inflammation, as well as infiltration of activated T-lymphocytes and expression of HLA class I antigens on hepatocytes, disappeared, or diminished in parallel after the therapy. In two of four patients, expression of HLA-DR on some periportal hepatocytes before the therapy also disappeared after the therapy. These observations imply that UDCA therapy decreases the hepatocellular expression of HLA antigens and thereby reduces or abolishes T-cell-mediated hepatocellular necrosis in primary biliary cirrhosis.