Search

Objectives: Although HAART has resulted in improved health outcomes for most HIV-infected individuals, liver failure has emerged as a major cause of morbidity and mortality in people co-infected with hepatitis B virus (HBV). In HBV mono-infected individuals, core deletion mutants are associated with more aggressive liver disease. As HIV accelerates HBV liver disease progression, we hypothesized that HIV-HBV co-infected individuals have increased frequency of core mutations including deletions. To test this hypothesis, we have analysed genome-length sequences of HBV DNA from patients both prior to and during antiviral therapy., Setting: Prospective HIV/HBV co-infected cohort study., Methods: Genomic length HBV DNA was amplified by PCR from the serum samples of ten HIV/HBV co-infected individuals and five HBV mono-infected individuals prior to the commencement of lamivudine therapy and again after nine to 74 months of treatment. The complete genomes were sequenced and in order to further analyse some mutations, their frequency was determined in additional HIV/HBV co-infected and HBV mono-infected individuals., Results: A novel -1G mutation was identified in the HBV precore and overlapping core genes that truncated the deduced precore/core proteins. The mutant genome was the dominant species in some HIV/HBV co-infected individuals and was more prevalent in HIV/HBV co-infected individuals than HBV mono-infected individuals. The mutation was also associated with high HBV DNA concentrations in HIV/HBV co-infected individuals. Additional mutations were identified in the core/precore and polymerase genes and regulatory regions., Conclusion: Mutations in the HBV core and precore genes may be contributing to disease pathogenesis in HIV/HBV co-infected individuals.

Background: Little is known about the prevalence and pattern of hepatitis B virus (HBV) mutations in HIV/HBV co-infected individuals on long-term lamivudine (3TC) therapy., Methods: HBV polymerase/envelope/basal core promoter/pre-core sequences from 81 HIV-HBV co-infected persons who received at least 6 months 3TC were compared to HBV reference sequences. Host and viral characteristics associated with HBV mutations were determined., Results: HBV viraemia was detected in 53 persons (65%) and was associated with lower CD4 cell count nadir and higher HIV RNA at the time of testing but not with 3TC duration. Known 3TC-resistant mutations occurred in 50% and 94% of viremic patients with < 2 years and > 4 years 3TC, respectively. The CD4 cell count at testing was significantly higher in those with 3TC-resistant mutations. The triple polymerase mutant (rtL173V, rtL180M, rtM204V), which behaves as a vaccine escape mutant in vitro, occurred in 17% of viraemic patients. Polymerase mutations that may confer resistance to other anti-HBV agents were also detected., Conclusions: In HIV-HBV co-infected patients, greater immunocompromise is associated with continued HBV viraemia while on 3TC, and development of 3TC-resistant mutations are inevitable with prolonged 3TC use. These mutant viruses may limit future therapeutic options due to cross-resistance or may produce HBV vaccine escape mutants. Thus, timing and selection of antiretroviral therapy is critical in this population.