Occult hepatitis B virus infection does not affect liver histology or response to therapy with interferon alpha and ribavirin in intravenous drug users with chronic hepatitis C

Background: the frequency and the impact of occult HBV infection in patients with chronic hepatitis C infection is still a matter of some controversy. Objectives: our aim was to evaluate the prevalence of occult HBV infection and assess its impact on liver biochemistry, HCV viral titre, liver histology and on outcome of therapy in patients with chronic hepatitis C. Study design: paired liver biopsies and serum samples were collected from 51 patients (84% IVDUS) with HBsAg negative chronic hepatitis C, and tested for HBV-DNA with nested PCR. Liver biopsies were further studied histologically, with morphometric analyses and immunostaining techniques. Twenty-five were treated with alpha Interferon and ribavirin and followed for at least 18 months. Results: HBV DNA was detected in 29.4% of liver tissue specimens and in only one (1.9%) serum sample. Three liver specimens were positive for surface gene, nine for core gene, three for both and none for the X gene. No significant difference in mean transaminase values, HCV viral titre, HCV genotype, or grading and staging and morphometric analysis was observed in patients with or without HBV DNA. Moreover, all 51 liver specimens were negative for both HBsAg and HBcAg. Sustained response to combination therapy was achieved in 40% of patients with and in 53% of patients without HBV DNA in the liver specimens (P=NS). Conclusions: HBV DNA is frequently found in the liver of patients with chronic hepatitis C. However, the lack of any significant impact on HCV viral titre, liver enzymes, histological parameters and response to therapy, suggests that in most cases HBV DNA detected in the liver by PCR may be either an integrated or low level replicative form.