Expression of cytokine-dependent immune adhesion molecules by hepatocytes and bile duct cells in chronic hepatitis C

Background/Aims: The pathogenesis of liver cell injury in chronic hepatitis C is poorly understood. To test whether immune-mediated mechanisms might be involved in the pathogenesis of liver cell injury during infection by hepatitis C virus, the expression of cytokine-dependent immune molecules by hepatocytes and bile duct cells during chronic hepatitis C was studied. Methods: In 35 patients, expression of class I and II HLA antigens, intercellular adhesion molecule (ICAM) 1, and lymphocyte function antigen (LFA) 3 was studied by immunohistochemistry and scored by a semiquantitative grading system. Statistical analysis was performed using Spearman's test and t test. Results: Class I HLA antigens were induced on hepatocytes in 20 cases. In all cases, HLA-DR, ICAM-1, and/or LFA-3 were detected on hepatocytes in piecemeal necrosis and intralobular clusters. Bile duct cells expressed HLA-DR in 32 cases and ICAM-1 and LFA-3 in 14 cases. Expression levels of immune molecules on hepatocytes correlated with aminotransferase activity (P < 0.035), histological activity (P < 0.001), and score of necrosis (P < 0.01). ICAM-1 expression on hepatocytes was higher in patients with intraportal lymphoid nodules (P = 0.005). Expression levels of ICAM-1 and LFA-3 on bile ducts correlated with the severity of bile duct damage (P < 0.015). Conclusions: These results suggest the involvement of immune-mediated mechanisms in the pathogenesis of liver cell injury in chronic hepatitis C.