内江市东兴区乙型肝炎病毒基因型、基本核心启动子和前C区变异分析

Analyses of hepatitis B virus genotype and mutation of basal core promoter and precore region in Dongxing District,Neijiang City

目的了解内江市东兴区乙型肝炎病毒(hepatitis B virus,HBV)慢性感染者中的HBV基因型和基本核心启动子(basal core promoter,BCP)、前C(Precore,PC)区变异。方法从慢性HBV感染者血清标本中提取病毒DNA,进行核苷酸测序,构建进化树确定基因型,分析BCP和前C区位点变异。结果S基因序列进化树分析显示,64份标本为B基因型,7份为C基因型,1份为I基因型;获取的53份BCP和PC序列标本中,25份标本发生A1762T/G1764A或G1896A变异;7份C基因型标本中6份发生A1762T/G1764A变异;B基因型标本以G1896A变异为主,并与A1762T/G1764A联合变异,HBeAg阳性组和阴性组之间G1896A和A1762T/G1764A变异率有差异(P均<0.05)。其他包括HBeAg前体启动子变异、1846位点核苷酸缺失等。结论内江市东兴区慢性HBV感染者以B基因型感染为主,1例为I基因型。B基因型HBV以G1896A变异最常见,并与A1762T/G1764A联合变异,C基因型HBV更容易发生A1762T/G1764A变异;BCP区的A1762T/G1764A变异和PC区的G1896A变异与疾病严重程度、肝硬化和肝癌发生相关。通过对HBV基因型和变异分析,能为病情诊断和治疗提供帮助。

Objective To explore genotypes and mutations of hepatitis B virus(HBV)in patients with chronic HBV infection in Dongxing district,Neijiang city.Methods Serum samples were collected to extract HBV DNA.Phylogenetic and nucleotide analyses were performed on S gene,basal core promoter(BCP)and precore(PC)region,respectively.Results Phylogenetic analysis of S gene showed 64 samples belonged to genotype B,7 samples to genotype C,and one sample belonged to genotype I,respectively.Of 53 samples available for BCP and PC regions,A1762T/G1764A or G1896A mutations occurred in 25 samples.In terms of genotype C,A1762T/G1764A was observed in 6 out of 7 samples.Regrading genotype B,the variation of G1896A was dominant and combined with A1762T/G1764A variation.The detection rates of G1896A and A1762T/G1764A were significantly different between HBeAg positive group and HBeAg negative group(P<0.05),respectively.Other mutations included HBeAg precursor initiation codon abortion and 1846 site deletion.Conclusions Genotype B was dominated in chronic patients of Dongxing district,and genotype I was only found in one patient.Genotype B HBV is most common with G1896A variation and combined with A1762T/G1764A variation,while genotype C HBV is more prone to A1762T/G1764A variation.Analyses of genotypes and BCP/PC mutations of HBV are helpful to predict disease severity and prognosis.