incidence of hepatitis b virus surface antigen (hbsag) mutations in naïve treated of chronic carriers from tehran metropolis, iran

abstract background: naturally occurred hepatitis b virus (hbv) with surface mutations in a variety of chronic hepatitis b (chb) patients who have received no vaccine or hbig bearing substitutions in surface protein, have been reported. objectives: current knowledge concerning the prevalence of these naturally occurring surface antigen mutations among iranian carriers is limited. patients and methods: in a retrospective cross-sectional study, 119 inactive hbv chronic carriers were enrolled. the surface gene was amplified, sequenced and subsequently aligned using international and national sequence database. results: all strains belonged to genotype d, subgenotype d1 and subtype ayw2. in 74 (62.18%) of patients, 146 (68.8%) out of 212 amino acid mutations occurred in different immune epitopes within surface protein, of which 28 (19.17%) in b cell, 37 (25.34%) in t helper and 81 (55.47%) inside ctl epitopes. 13 (8.9%) and 15 (10.27%) of amino acid substitutions occurred outside and within the “a” determinant in major hydrophilic region (mhr). while 11 (9.24%) and 77 (64.7%) patients who harbored amino acid mutations, were hbeag and anti-hbe positive, respectively (p=0.004). 9 and 63 amino acid mutations were occurred in different hbsag epitopes in hbeag and anti-hbe positive patients, respectively (p=0.04). conclusions: hbv mutants within the surface immune epitopes seem to be extremely common among chronic carriers from tehran, especially those who are anti-hbe positive, indicating that after hbeag seroconversion, due to the selection pressure of e antibody, the occurrence of mutation is an inevitable effect of the evolutionary process.