自然发生和拉米夫定诱导的乙型肝炎病毒逆转录酶区序列变异的特征

Characteristic of Hepatitis B Virus Polymerase Gene Mutants Naturally Occurred or Lamivudine-induced in Patients with Chronic Hepatitis B

目的研究慢性乙型肝炎(CHB)患者在自然状态或在拉米夫定(LVD)长期治疗过程中乙型肝炎病毒(HBV)逆转录酶区(RT)序列变异出现的时机和特点。方法120例CHB患者按测序时机分3组:Ⅰ组初治患者25例,Ⅱ组病毒学突破患者74例,Ⅲ组病毒学部分应答患者21例。所有患者留血清标本,提取血清HBV-DNA,应用PCR扩增,直接测序HBV RT区,Chromas 2.0软件分析HBV P基因RT区变异,同时使用Clustalx1.81.msw进行基因型分析。结果120例CHB患者中,B型34例(28.3%),C型85例(70.8%),B/C型1例(0.8%)。Ⅰ组患者中,2例(8.0%)出现rt变异原发性LVD耐药(LVDr),其中1例为rtM204V+rtL180M变异,另1例为rtL180M变异与野毒株并存;Ⅱ组患者中,67例(90.5%)出现继发性LVDr变异,rt变异位点为rtM204V/I、rtL180M、rtV173L/M、rtV207M/L/ I、rtA181T、rtM250L;Ⅲ组患者中,出现rtV191I、rtF221Y变异各1例,没有出现LVDr相关的变异。结论CHB患者在自然状态下和病毒学突破时HBV可出现LVDr变异,治疗前后对HBV逆转录酶区(RT)序列分析可指导临床抗HBV药物的选择。

Objective To investigate the frequency and profile of polymerase gene mutants naturally occurred and lamivudine（LVD） induced in patients with chronic hepatitis B （CHB）. Methods One hundred and twenty patients with CHB were divided into three groups according to times of sequencing HBV DNA. Group Ⅰ in which HBV DNA was detected pre-administration with LVD was taken as baseline, in group Ⅱ and m virologic rebound occurred or virologic response partially occurred during long-term LVD therapy, respectively. The difference of nucleotide and amino acid of HBV DNA was classified by Chromas 2.0 software. Genetyping of HBV was analyzed by Clustalxl.81.msw. Results In 28.3%（34/120） patients HBV was genetype B, in 70.8%（85/120） genetype C, and in 0.8% （1/120） genetype B/C. In 8.0% patients in group Ⅰ naturally occurring genotypic resistance occurred in which one was rtM204V＋ rtL180M and the other rtL180M/wild type. The frequencies of occurring LVD resistance HBV in group Ⅱ and group Ⅱ were 90.5% and 0 respectively. Genotypic resistance with LVDr HBV was rtM204V/ I, rtL180M rtV173L/M, rtV207M/L/I, rtA181T and rtM250L. Conclusion Naturally occurring polymerase gene RT region mutation is uncommon. Mutation usually develops in the patients experiencing a virologic rebound in LVD therapy. Analysis of hepatitis B virus polymerase gene is valuable in chosing anti-HBV drugs.