In situ characterization of mononuclear cell phenotype in intrahepatic lymphoid follicles in patients with chronic viral hepatitis.

The author examined liver biopsy specimens obtained from 596 patients with chronic viral hepatitis to clarify the role of lymphoid follicle formation in the portal spaces. Lymphoid follicles were observed more frequently in chronic hepatitis non-A non-B than in chronic hepatitis B and were also common in patients with anti-hepatitis C virus-positive non-A non-B hepatitis. Immunohistology revealed that these hepatic lymphoid follicles resembled the lymphoid follicles of synovial tissue in rheumatoid arthritis. In situ hepatitis B virus markers were examined in 40 patients with chronic hepatitis B showing lymphoid follicles. Among these, hepatitis B surface antigen (HBsAg) was detected in liver cells as well as in the center of the follicles in 19 patients (47.5%). By immune electron microscopy, the author confirmed the HBsAg-positive cells in the lymphoid follicles as follicular dendritic cells. These cells appeared to be a site for antigen trapping in the follicles, therefore, the intrahepatic lymphoid follicles are suggested to play a role in immune response to HBsAg in chronic hepatitis B.