广西地区乙型肝炎病毒无症状携带者乙型肝炎病毒前C区突变分析

目的 调查广西地区乙型肝炎病毒（HBV）无症状携带者HBV前C区基因突变株的流行情况。方法 用套式聚合酶链反应（PCR)对77例广西南部，北部地区人群HBV无症状携带者血清HBV前C区进行扩增，阳性者用直接测序法进行序列分析。结果 39例HBsAg无症状携带者血清HBVDNA阳性，阳性率为50.7%(39/77)，突变株出现率为22.1%(17/77)。南部地区阳性率为55.6%(20/36)，其中6份标本出现突变株，占30%，常见的突变类型是nt1858位发生点突变（T→C),只有一份标本在nt1896发生点突变（G→A），导致终止密码产生，该标本同时伴有nt1837点突变（A→G）；北部地区阳性率为46.3%(19/41)，其中有11份标本出现突变株，占57.9%,常见的突变类型是ny1896位发生点突变（G→A），这些标本中有4份同时在nt1846发生点突变（A→T），2份同时在nt1862发生点突变（G→T)；标本734分别在nt1856,1858发生点突变（C→T，T→C）。结论 广西地区HBV无症状携带者HBV前C区突变株的流行率居全国中等水平，广西南部，北部是否存在主要突变类型不同值得进一步研究。

The prevalence of hepatitis B virus precore mutant isolated from asymptomatic carriers in Guangxi

OBJECTIVE: In order to understand the prevalence of hepatitis B virus (HBV) precore mutants isolated from asymtomatic carriers in Guangxi. METHODS: Nested polymerase chain reaction (nPCR) was used for amplification of HBV DNA precore in 77 carrier sera, followed by HBV DNA nPCR products sequencing using direct sequencing. RESULTS: 50.7% of 77 carriers was positive for HBV DNA with a prevalence of mutants 22.1% (17/77). HBV DNA positive rate in the southern part of the autonomous region was 55.6% (20/36). Six of them were mutants, counting for 30%. The common mutation in the southern part was seen T-->C at nt1858 while nt1896 stop mutation was discovered in one sample only, which was accompanied by point mutation at nt1837 (A-->G). HBV DNA positive rate in the northern part was 46.3% (19/41) with 11 of them were mutants, counting for 57.9%. The common mutation in that area stopped at nt1896. Among samples with stopped mutation, 4 samples had mutation at nt1846 (A-->T), 2 samples at nt1862 (G-->T). Both mutation at nt1856 (C-->T) and nt1858 (T-->C) could be seen in sample 734. CONCLUSIONS: The prevalence of HBV precore mutant in asymptomatic carriers in Guangxi was at the average level in China. Further study is needed to determine the difference between the southern and the northern part of the region in the common type of mutation exists.