Epithelioid cell granulomas in chronic hepatitis C: immunohistochemical character and histological marker of favourable response to interferon-alpha therapy.

AIMS: The clinicopathological significance of intrahepatic epithelioid cell granulomas in chronic hepatitis C was determined.

METHOD AND

RESULTS

Granulomatous lesions were surveyed in 542 liver biopsy specimens and were immunohistochemically examined. We also tested whether this lesion is a marker of response to interferon-alpha therapy in chronic hepatitis C. Granulomatous lesions in hepatic lobules and/or portal tracts were identified in 11/542 (2%) cases with chronic hepatitis C. Granulomas were positive for HLA-DR and beta 2-microglobulin, and were surrounded by T-cells. Among them, three chronic hepatitis C cases showed portal granulomas with mild biliary epithelial damage. Bile ducts showing mild epithelial damage in chronic hepatitis C were positive for beta 2-microglobulin, but negative for HLA-DR, while both antigens were frequently expressed in damaged bile ducts in primary biliary cirrhosis (PBC). All five cases of chronic hepatitis C with granulomas who had interferon-alpha therapy and were followed up and were found to have responded well.

CONCLUSION

Granulomas showed the same immunohistochemical phenotypes, though the expression of HLA-DR on bile ducts in PBC but not in chronic hepatitis C suggests a different pathogenesis. Granulomas may predict a favourable response to interferon-alpha therapy in chronic hepatitis C.