Cellular immune responses in patients with dual infection of hepatitis B and C viruses: dominant role of hepatitis C virus.

Several lines of evidence have suggested that immune mechanisms are involved in the pathogenesis of hepatitis B virus (HBV)- and hepatitis C virus (HCV)-related hepatitis. Study of patients with dual HBV and HCV infection raises the question of which is etiologically more relevant in determining the liver cell damage. To address this issue, proliferation of peripheral blood mononuclear cells (PBMCs) in response to a panel of HBV and HCV antigens was assayed in 13 patients with chronic dual hepatitis B and C, 7 patients with chronic hepatitis B, 7 patients with chronic hepatitis C, and 6 patients with hepatitis B surface antigen (HBsAg) carrier state. Although HBV or HCV hepatitis patients had a significant response to HBV or HCV antigens, respectively, the patients with dual hepatitis B and C exclusively responded to HCV antigens, but not to HBV antigens. One patients who was seropositive for both HBV-DNA and HCV-RNA showed a low response to HBV antigens initially but lost the response 3 months later and became responsive to more HCV antigens. These findings suggest that HCV has a dominant role in the immune response of the patients with dual HBV and HCV infection.