Mutations in reverse transcriptase region of HBV affect Hepatitis B surface antigen titers and its correlation with HBV DNA

Introduction: The impact of mutations in the reverse transcriptase region of HBV on serum HBsAg titer and its correlation with HBV DNA is largely unknown. Methodology: A total of 644 patients, with a history of lamivudine or adefovir dipivoxil resistance who underwent genotypic resistance tests, were enrolled in this study. Serum HBsAg, hepatitis B e antigen and HBV DNA were quantified, and the HBV RT region was sequenced and analyzed. Then, the patients were divided into five sub-groups, including M204I/V, L180M+M204I/V, A181T/V, N236T and A181T/V+N236T according to the mutation spectra. Results: HBsAg was lower in the wild-type and A181T/V+N236T groups as compared to the M204I/V, L180M+M204I/V and N236T groups. HBsAg was positively correlated with HBV DNA levels in the wild-type group (r = 0.322, p < 0.01), as well as in the M204I/V, L180M+M204I/V, A181T/V, and N236T subgroups, while no correlation was found in the A181T/V+N236T subgroup (r = 0.159, p = 0.217). Moreover, for patients with N236T mutation, HBsAg was positively correlated with HBV DNA level in the HBeAg negative group (r = 0.435, p = 0.016), but not in the HBeAg positive group (r = 0.105, p = 0.594). For patients with A181T/V or N236T mutation, HBsAg was positively correlated with HBV DNA in older patients (≥ 40 years), but not in younger patients (< 40 years). Conclusions: Serum HBsAg titer and its correlation with HBV DNA may be affected by mutations in the reverse transcriptase region of HBV, that should be re-evaluated in patients with antiviral resistance.

Ultradeep Sequencing for Detection of Quasispecies Variants in the Major Hydrophilic Region of Hepatitis B Virus in Indonesian Patients

Quasispecies of hepatitis B virus (HBV) with variations in the major hydrophilic region (MHR) of the HBV surface antigen (HBsAg) can evolve during infection, allowing HBV to evade neutralizing antibodies. These escape variants may contribute to chronic infections. In this study, we looked for MHR variants in HBV quasispecies using ultradeep sequencing and evaluated the relationship between these variants and clinical manifestations in infected patients. We enrolled 30 Indonesian patients with hepatitis B infection (11 with chronic hepatitis and 19 with advanced liver disease). The most common subgenotype/subtype of HBV was B3/adw (97%). The HBsAg titer was lower in patients with advanced liver disease than that in patients with chronic hepatitis. The MHR variants were grouped based on the percentage of the viral population affected: major, ≥20% of the total population; intermediate, 5% to <20%; and minor, 1% to <5%. The rates of MHR variation that were present in the major and intermediate viral population were significantly greater in patients with advanced liver disease than those in chronic patients. The most frequent MHR variants related to immune evasion in the major and intermediate populations were P120Q/T, T123A, P127T, Q129H/R, M133L/T, and G145R. The major population of MHR variants causing impaired of HBsAg secretion (e.g., G119R, Q129R, T140I, and G145R) was detected only in advanced liver disease patients. This is the first study to use ultradeep sequencing for the detection of MHR variants of HBV quasispecies in Indonesian patients. We found that a greater number of MHR variations was related to disease severity and reduced likelihood of HBsAg titer.