Banerjee Arup, Chandra Partha K, Datta Sibnarayan, Biswas Avik, Bhattacharya Prasun, Chakraborty Subhasis, Chakrabarti Sekhar, Bhattacharya Sujit Kumar, Chakravarty Runu
ICMR Virus Unit, Kolkata, ID & BG Hospital Campus, Kolkata, India.
J Clin Virol. 2007 Dec;40(4):312-7. doi: 10.1016/j.jcv.2007.08.009. Epub 2007 Nov 7.
Genetic mutation might account for the presence of hepatitis B virus (HBV) DNA among antiHBc only individuals. The aim of the study was to assess the prevalence and significance of surface gene mutations among antiHBc only cases in our population.
Three hundred and three antiHBc(+) sera of adults (mean age, 33.7+/-11.0; range 18-65 years) as well as HBsAg(+)/HBV DNA(+) (n=19) controls were included in this study. Surface gene and basal core promoter (BCP)-precore region were amplified and surface gene was analyzed after direct sequencing.
One hundred and seventy-eight out of 303 (58.8%) was antiHBc only, 39/171 (22.8%) of them was HBV DNA(+). Genotypes A, C, D were found among both HBsAg(+) and antiHBc(+) samples. Single or multiple amino acids substitutions were found in 82% samples, however, G145R vaccine escape mutation was rare. Individuals having substitutions within as well as outside major hydrophilic loop (MHL) region were detected; some of these mutations were in overlapping RT domain of polymerase (Pol) gene.
The existence of occult HBV infection among antiHBc only individuals could not be explained fully by mutations in the 'a' determinant region of surface gene in our population.
基因突变可能是仅抗-HBc阳性个体中存在乙型肝炎病毒（HBV）DNA的原因。本研究旨在评估我国仅抗-HBc阳性病例中表面基因突变的发生率及其意义。
本研究纳入了303份成人抗-HBc（+）血清（平均年龄33.7±11.0岁；范围18 - 65岁）以及19份HBsAg（+）/HBV DNA（+）对照血清。对表面基因和核心启动子（BCP）-前核心区进行扩增，并在直接测序后分析表面基因。
303份样本中有178份（58.8%）仅抗-HBc阳性，其中39/171（22.8%）HBV DNA阳性。在HBsAg（+）和抗-HBc（+）样本中均发现了A、C、D基因型。82%的样本中发现了单个或多个氨基酸替换，然而，G145R疫苗逃逸突变很少见。检测到在主要亲水环（MHL）区域内以及区域外有替换的个体；其中一些突变位于聚合酶（Pol）基因的重叠RT结构域。
在我国人群中，仅抗-HBc阳性个体中隐匿性HBV感染的存在不能完全用表面基因“a”决定簇区域的突变来解释。
