Reactivation of Occult Hepatitis B Virus Infection During Long-Term Entecavir Antiviral Therapy.

Up to now, it has not been clear whether occult hepatitis B virus (HBV) infection (OBI) can be treated with antiviral therapy whether OBI can develop drug resistance gene mutation or not. We report a middle-aged female patient with OBI who showed HBV reactivation (HBVr) during more than 3 years of intermittent entecavir (ETV) antiviral therapy: seropositive HBV surface antigen (HBsAg), increased e antigen (HBeAg), and repeatedly elevated serum HBV DNA. Genotype analysis showed that the patient was infected with HBV type B. Genetic sequencing of HBV showed the mutants of S143T, D144G, and G145R in the S gene region, and the mutant of site 1896 in the pre-Core region coexisted with the wild type (G1896A/G). No mutation was found in other HBV gene segments. Drug resistance gene analysis found RtL229W mutant, resistant to lamivudine but sensitive to ETV and other nucleoside analogs. This case of OBI provides us with the following clinical experiences: Firstly, it is necessary to detect HBV genotype, mutation, and drug-resistant genes at the initial diagnosis, which can be helpful for reasonable treatment. Secondly, identifying the risk factors and mechanisms associated with HBVr could help quantify the risk of HBVr and manage the clinical consequences. Thirdly, the OBI patients with hepatitis B e antigen-positive, HBV DNA > 1 × 103 IU/ml should be recommended regular and continuous antiviral therapy as soon as possible to prevent the occurrence of hepatocirrhosis and hepatocellular carcinoma (HCC).

Construction of mutant gene of HBV and investigating its biological significance / 中华传染病杂志

Objective To study the biological significance of the common mutant preC/C gene in clinical HBV in China. Methods Site directed mutagenesis based on the unique enzyme site elimination was used to construct eukaryocyte expression vector with mutant HBV/C gene(V60、G87、L97). Expression vectors with wild and mutant preC/C gene were transferred into HepG2 cell. Culture supernatant was detected by ELISA for HBeAg. Results Result of DNA sequencing showed that the constructed mutant HBV preC/C gene had only one specific site variation compared with the wild type sequence. Goal DNA fragment was detected positive in the HepG2 cells transferred with wild and mutant preC/C gene. A value of HBeAg in the supernatant of the cells harboring L97 variant was higher than that of the wild and other variant strains( P