Significance of CD30-positive lymphocytes in livers in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by the destruction of intrahepatic small bile ducts. It is generally believed that cellular immune mechanisms, particularly T cells, cause this bile duct damage. CD30, which is inducible on selected T cells following activation, is regarded as important for B cell hyperactivity in several autoimmune diseases. In this study, we have attempted to examine CD30-expressing lymphocytes in PBC with respect to B cell hyperactivity.

We surveyed and counted CD30+ lymphocytes in liver sections from 13 patients with PBC and 36 control livers, including chronic viral hepatitis, extrahepatic biliary obstruction and normal liver by immunohistochemical staining.

Several CD30+ lymphocytes were localized in inflamed portal tracts and also accentuated around the bile ducts in PBC livers, but they were rarely detected in control liver sections. The numbers of CD30+ lymphocytes in PBC were significantly higher than in control groups (P<0.01). Double immunohistochemical staining revealed that these CD30+ lymphocytes expressed CD3 as well as CD4. The number of CD30+ lymphocytes, moreover, correlated with that of immunoglobulin (Ig)A-containing cells (r=0.72) in PBC, although no such correlation between CD30+ lymphocytes and IgM or IgG-containing cells was obtained.

These findings indicate that intrahepatic CD30+ lymphocytes have a role in IgA type, B cell abnormal hyperactivity with respect to the pathogenesis of portal tract and bile duct lesions in PBC.