Mutations in hepatitis B virus DNA from patients with coexisting HBsAg and anti-HBs

BackgroundThe serological markers with coexistence of hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) of hepatitis B virus (HBV) infection were rare pattern. The virological significance, immune response and clinical outcome of these patients remain largely unknown.ObjectivesThis research explores the relationship between this serological profile and HBV genome variants.Study designWe studied 35 patients both carrying HBsAg and anti-HBs (group I), and 70 patients with HBsAg positive but anti-HBs negative (group II, served as control). The HBV genome sequences were obtained by direct sequencing of polymerase chain reaction (PCR) products.ResultsThe amino acid (aa) variation within major hydrophilic region (MHR), especially in the first loop (aa124-137) of “a” determinant in group I is significantly higher than those in group II. The aa variation of cytotoxic lymphocyte (CTL) epitope in HBsAg (aa87–aa95) in group I is also significantly higher than that in group II. Interestingly, the basal core promoter (BCP) double mutations (A1762T/G1764A) in group I is significantly higher than those in group II as well.ConclusionsIn patients with HBV infection, the coexistence of HBsAg and anti-HBs is associated with an increased aa variability in several key areas of HBV genome. The molecular characteristic of HBV in HBsAg and anti-HBs positive patients is distinct and worth further studies.