Fc gamma receptor expression on hepatic macrophages and histological activity of chronic hepatitis

Aims/Background: Activated liver macrophages in chronic hepatitis express a high affinity receptor for IgG named Fc gamma RI. This study was performed to find the difference in Fc gamma RI expression between chronic hepatitis B (CHB) and C (CHC) with reference to histological activity. Methods: Cons ecutive patients with CHB (20 cases) and CHC (25 cases) were enrolled in th e study. Inflammatory activity was evaluated using the modified histologica l activity index (HAI). Fc gamma RI-positive macrophages were quantitativel y measured by computer assisted morphometry. Results: Total HAI score was s ignificantly higher in CHB than in CHC. Confluent necrosis was observed in significantly higher frequency in CHB at Stages 3-5 than in CHC. The percen tage area of Fc gamma RI-positive macrophages was significantly higher in C HB than in CHC. In CHB, the percentage area of Fc gamma RI-positive macroph ages correlated with total HAI (<0.01) as well as the degree of confluent n ecrosis (<0.01), interface hepatitis (<0.05) and portal inflammation (<0.05 ). Fc gamma RI-positive macrophages accumulated mainly at the site of confl uent necrosis. In CHC, no correlation was observed between activated macrop hages and any histological categories. Conclusion: These results suggest th at Fc gamma RI-positive macrophages are associated with confluent necrosis in CHB, which is more common in CHB patients than in CHC.