Abstract: AIM: To study the role of intrahepatic HBV DNA in antiviral therapy.METHODS: 71 patients with HBeAg-positive chronic hepatitis B were studied. Twelve patients were treated with INF-α2b;thirty-five patients received lamivudine;twenty-four patients were administered by sequential therapy with Lamivudine-INF-α2b (at first, lamivudine alone from first to 6th month, then lamivudine combined with INF-α2b from 7th to 8th month, finally INF-α2b alone from 9th to 12th month). Liver biopsy specimens were obtained before and after treatment.Blood samples were collected once a month during the period of treatment, in the thirdmonth, and in the sixth month after cessation of therapy.Serum and intrahepatic HBV DNA were measured quantitatively by real-time polymerase chain reaction.HBV genotypes were analyzed by PCR-RFLP.RESULTS: There was no significant difference in intrahepatic HBV DNA levels between the patients infected by HBV genotype C (60 cases) and genotype B (10 cases) (P >0.05).Intrahepatic HBV DNA logarithm levels in the patients with therapy response decreased from (5.9 ±1.0) to (4.5 ±1.2) (P <0.05).Patients with intrahepatic HBV DNA logarithm level <5 after treatment achieved higher serum HBV DNA undetectable rate and serum ALT normalization.However, after withdrawal of antiviral drugs, the mean levels of serum HBV DNA and ALT flared up.CONCLUSION: The intrahepatic HBV DNA load can be significantly inhibited by antiviral agents.The patients with lower levels of intrahepatic HBV DNA have better therapy response. Intrahepatic HBV DNA loss may be a significant marker for the endpoint of antiviral treatment.There is no significant difference in intrahepatic HBV DNA levels between the patients infected with HBV genotype C and genotype B.

Key words: sequential treatment, lamivudine, interferon, HBV DNA, liver histology