Clinical and virological significance of the co-existence of HBsAg and anti-HBs antibodies in hepatitis B chronic carriers.

The co-existence of hepatitis B surface antigen (HBsAg) and anti-HBs antibodies (HBsAb) in serum of hepatitis B virus (HBV)-chronic carriers has been previously associated with HBsAg-amino acid (aa) substitutions. However, the aa pattern of HBV-reverse transcriptase (RT) and the clinical settings associated with this serological profile remain largely unknown. We studied thirteen HBsAg-positive/HBsAb-positive patients. Newly diagnosed HBsAg-positive/HBsAb-negative patients (n=51) served as controls. HBsAg/RT sequences were obtained using in-house protocols. HBsAg-positive/HBsAb-positive patients were predominantly immunosuppressed (69%). Five presented advanced liver fibrosis. HBV DNA >5.0 log(10) copies/ml was significantly more frequent than in controls. A significantly higher aa variability was observed versus controls within HBsAg major hydrophilic region (MHR), especially the a-determinant, and within RT for regions overlapping the MHR, the a-determinant, and HBsAg C terminal region where drug resistance mutations occur. Further studies are needed to determine whether this higher HBsAg/HBV-RT variability might favor dissemination of anti-HBsAb escape HBV mutants and concomitantly alter nucleos(t)ide analogs efficacy.