Variability of the preC/C region of hepatitis B virus genotype A from a South African cohort predominantly infected with HIV

Simnikiwe H. Mayaphi*, Desmond J. Martin, M. Jeffrey Mphahlele, Jason T. Blackard, Sheila M. Bowyer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Hepatitis B virus (HBV) is a serious global health problem, and HBV genotype is an important determinant of disease progression and treatment outcome. The aim of this study was to assess variations of the precore/core (preC/C) region in HBV genotype A. Sequencing of the preC/C and surface (S) genes of HBV was performed on plasma samples from 20 HBV/HIV co-infected and 5 HBV mono-infected individuals. All preC/C study sequences clustered with subgenotype A1, except for two which clustered with subgenotype D4 reference strains. The nucleotide and amino acid variability was far higher in the preC/C region than in the S region. Mutations associated with reduction or failure of HBV e-antigen (HBeAg) production were observed, with a preC start codon mutation being common (24%). Other mutations (e.g., P5H/L and I97L) associated with severe liver disease were also noticed, some of which were located in the major histocompatibility restricted sites. PreC/C intergenotype nucleotide divergence was >7%, while subgenotypes differed by 2.5-7%. Several study sequences were highly divergent from other African subgenotype A1 strains. This study showed that HBeAg-negative chronic hepatitis B is underestimated in subgenotype A1, and also highlighted the variant South African A1 strains. The major advantage of preC/C sequencing is that it informs patient management as HBeAg-negative chronic hepatitis B responds poorly to conventional interferon-α therapy, and some guidelines treat HBeAg-negative chronic hepatitis B differently from HBeAg-positive chronic hepatitis B. These data suggest that subgenotype A1 may be more involved in severe HBV-related diseases.

Original languageEnglish
Pages (from-to)1883-1892
Number of pages10
JournalJournal of Medical Virology
Volume85
Issue number11
DOIs
Publication statusPublished - Nov 2013
Externally publishedYes

Keywords

  • Amino acids
  • Genotyping
  • HBeAg-negative chronic hepatitis B
  • Mutations
  • Nucleotides

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