Backgrounds/Aims
This study focuses on the pathogenesis of inflammatory reaction and cell necrosis in patients with chronic viral hepatitis and examines the possible effects of follicular dendritic cells, HLA-DR and CD8+ presenting lymphocytes by analyzing their expression and the histological activity index (HAI) in liver tissues. Methods: Liver biopsy specimens were obtained from 59 patients with chronic hepatitis B and from 26 patients with chronic hepatitis C. The expressions of dendritic cells, HLA-DR and CD8+ presenting lymphocytes were determined by immunohistochemical stain. Results: The incidence of lymphoid follicle and/or lymphoid aggregates in portal tracts of the liver was higher in chronic hepatitis C than it was in chronic hepatitis B (84.6% vs. 15.3%, p=0.000). Follicular dendritic cells were exclusively expressed within lymphoid follicles and/or lymphocyte aggregates in portal areas. HLA-DR restricted cells were mainly observed in portal and periportal areas as well as in the area of piecemeal necrosis. CD8+ lymphocytes were diffusely expressed in portal and periportal areas and within intralobular parenchymal sinusoids. The expression of dendritic cell and HLA-DR was more frequently observed in moderate chronic hepatitis than in mild chronic hepatitis. While that of CD8+ lymphocyte expression was more frequent in severe chronic hepatitis with a high HAI score. Conclusions: The follicular dendritic cells may trap viral antigens in intraportal lymphoid follicle and present them to HLA-DR and CD8+ presenting lymphocytes. It is suggested that the associated expression of dendritic cells, HLA-DR and CD8+ presenting lymphocytes in liver tissues may play one of the biological role in immune injury in chronic viral hepatitis.
