乙型肝炎病毒C基因启动子及前C变异的动态研究

Dynamic changes of basal core promoter and pre core mutants of hepatitis B virus in patients with chronic hepatitis B virus infection

目的明确乙型肝炎病毒（ＨＢＶ）Ｃ基因启动子（ＢＣＰ）与前Ｃ变异株在慢性乙型肝炎患者中的动态消长，及与ＨＢｅＡｇ血清学状态的关系。方法对３２例慢性乙型肝炎患者的１０５份系列血清进行错配聚合酶链反应（ＰＣＲ）－限制性片段长度多态性分析，并对其中１５例患者系列血清标本的ＰＣＲ产物进行直接测序。结果ＢＣＰ和Ａ８３变异株感染率均明显增高（６２．５％＞４６．９％；３１．３％＞１２．５％）；ＢＰＣ变异株更多地（１４／１６）表现为优势积累，且先于ＨＢｅＡｇ血清阴转；ＢＣＰ野株／变异株比例变化影响ＨＢｅＡｇ血清学的稳定性。结论两种类型的变异株在炎症活动中均具有选择优势，最终造成ＨＢｅＡｇ（－）的ＨＢＶ感染；可能与ＨＢＶ感染之持续有关。

Objectives To clarify the association of hepatitis B virus mutants in basal core gene promoter and pre c region with serum HBeAg state and persistent HBV infection. Methods 32 patients, who infected with hepatitis B virus and suffered from several exacerbation during the course of this diseae, were followed up for an average of 20.8 months. Using two mis matched primers to amplify BCP and pre c gene fragments, in combination with restricted fragment length polymorphism assay, we studied the presence of these two mutants(nt 1762A→T, 1764G→A and nt1896G→A)in 105 serum samples. Direct sequencing was performed on 15 patients′serial samples to identify the efficiency of these rapid and simple methods and other variations in these regions.Results The presence of these two kinds of mutants increased during the following up, (62.5%>46.9%; 31.3%>12.5%). In most cases, two mutants prevailed and finally displaced the wild type virus; the serology of HBeAg was affected predominantly by the ratio of BCP mutant to wild type.Conclusion BCP and pre c mutants emerged in the course of chronic infection and were selected positively by the inflammation activity. The serological conditions of HBeAg were changed when the predominant situationsof these two mutants were established. The survival of these two mutants implied that mutations in these two regions may contribute to the persistent infection of hepatitis B virus.