Department of Virology, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria; Department of Microbiology, Faculty of Science, Ekiti State University, Ado Ekiti, Ekiti State, Nigeria.
Department of Virology, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria.
Int J Infect Dis. 2015 Oct;39:102-9. doi: 10.1016/j.ijid.2015.08.008. Epub 2015 Aug 14.
In 2012, the first Nigerian Hepatitis B Virus (HBV) immune escape mutant (IEM) case was detected in a pregnant woman in southwestern Nigeria. Consequently, this study was designed to investigate the presence and possible circulation of IEMs amongst asymptomatic community dwellers in southwestern Nigeria.
Blood specimens collected from 438 asymptomatic community dwellers were screened for HBsAg using ELISA technique. Subsequently, the S-gene was amplified in HBsAg positive samples by a nested PCR protocol, and amplicons sequenced. Isolates were then subtyped by amino acid residues at positions 122, 127, 134 and 160, and genotyped by phylogenetic analysis.
Of the 31 (7.08%) samples positive for HBsAg, the ∼ 408 bp Sgene fragment was successfully amplified and sequenced in 27. Samples obtained from 4 patients could not be amplified due to low titres. Sequence data from only 15 of the isolates could be analysed further as eight of the remaining 12 had multiple peaks while the rest three showed no similarity to any HBV gene when subjected to BLAST analysis. Thirteen of the 15 isolates were identified as genotype E. Eleven of which were subtyped as ayw4 while the remaining two could not be subtyped due to sR122Q/P substitutions. The last two isolates that could not be genotyped and subtyped had other mutations in the "a" determinant associated with IEMs.
This study confirmed presence and circulation of HBV IEM in Nigeria, the country's inclusion in the genotype E crescent, and the value of phylogenetic analysis in HBV identification.
2012 年，在尼日利亚西南部的一名孕妇中发现了首例尼日利亚乙型肝炎病毒（HBV）免疫逃逸突变（IEM）病例。因此，本研究旨在调查无症状社区居民中 IEM 的存在和可能传播情况。
采用 ELISA 技术检测 438 名无症状社区居民的血样中是否存在 HBsAg。随后，采用巢式 PCR 方案扩增 HBsAg 阳性样本中的 S 基因，并对扩增子进行测序。根据位置 122、127、134 和 160 的氨基酸残基对分离株进行亚型分型，并通过系统发育分析进行基因分型。
在 31 份（7.08%）HBsAg 阳性样本中，成功扩增并测序了 27 份约 408bp 的 S 基因片段。由于滴度低，从 4 名患者中获得的样本无法扩增。由于 8 个分离株存在多个峰，其余 12 个分离株的剩余 3 个分离株在 BLAST 分析中与任何 HBV 基因均无相似性，因此只能对其中 15 个分离株的序列数据进行进一步分析。15 个分离株中有 13 个被鉴定为基因型 E，其中 11 个被亚分型为 ayw4，其余两个由于 sR122Q/P 取代而无法亚分型。最后两个无法进行基因分型和亚分型的分离株在“a”决定簇中存在与 IEM 相关的其他突变。
本研究证实了尼日利亚存在 HBV IEM 及其传播，该国被纳入基因型 E 新月形，以及系统发育分析在 HBV 鉴定中的价值。
