HCV and HBV coexist in HBsAg-negative patients with HCV viraemia: possibility of coinfection in these patients must be considered in HBV-high endemic area.

Hepatocellular carcinoma (HCC) is one of the most common cancers and is highly associated with hepatitis B virus (HBV) infection in Korea. The role of HBV and hepatitis C virus (HCV) in HCC patients who are negative for hepatitis B surface antigens (HBsAg) remains poorly defined. It has been suggested that HCV core protein may impair the polymerase activity of HBV in vitro, potentially lowering HBV titre in coinfected patients. Therefore, routine enzyme immunoassay may not detect HBV, in spite of the presence of HBV viraemia in low titres. The aim of this study was to confirm the coexistence of HBV viraemia in hepatitis C-infected patients with HCC who have apparent HBsAg seronegativity and to establish the need for clinical reinterpretation of enzyme immunoassay (EIA) serological tests of HBsAg in patients with HCV viraemia and HCC. The serological profiles of HBV and HCV in 616 patients with HCC were analysed and the coinfection rate of HCV and HBV investigated. Sera were obtained from 16 patients who were both anti-HCV and HCV-RNA positive but HBsAg negative, and tested for HBV by polymerase chain reaction (PCR). Eleven non-A and non-B chronic hepatitis patients without HCC who had the same profiles of anti-HCV, HCV-RNA, and HBsAg were tested for HBV by PCR. As a control group, sera were obtained from 15 patients with HCC and 30 non-A and non-B chronic hepatitis patients without HCC; both were anti-HCV, HCV-RNA, and HBsAg negative and tested for HBV PCR. Of the 616 patients with HCC, 450 (73.1%) had current HBV infection, 48 (7.8%) had anti-HCV antibodies, and nine (1.5%) had viral markers of both HCV and HBV by serological profiles. Of the 27 patients with HCV viraemia and HBsAg seronegativity (16 with HCC; 11 with non-A non-B chronic hepatitis), 14 (51.9%) showed HBV viraemia by PCR. In contrast, of the 75 patients in the control group (45 with HCC; 30 with non-A and non-B chronic hepatitis) who were both HCV PCR negative and HBsAg negative, five (11.1%) showed HBV viraemia by PCR. The PCR for HBV revealed coexistent HBV viraemia in HCV viraemia patients, despite HBsAg negativity by EIA. In HBV-endemic areas, the possibility of coinfection of HBV in HBsAg-negative patients with HCV viraemia should be considered and molecular analysis for HBV-DNA performed.