HCV高变区基因变异的动态观察及同源性分析

目的　了解HCV在其感染者体内动态变异情况 ,为输血后丙型肝炎的诊断及因果关系鉴定提供依据。方法　采用RT PCR和序列测定的方法对HCV基因组中高变区 (HVR1和HVR2 )基因变异作横断面调查 ,同时对3名丙型肝炎病人作间隔 3个月、为期 1年的随访观察。结果　不同型HCV毒株间的同源性只有 5 6 .99%～ 6 0 .88% ;不同亚型毒株间同源性为 6 5 .0 9%～ 6 8.80 % ;同一亚型内毒株间的同源性为 80 .0 5 %～ 96 .4 0 % ,并有地理分布的特点。 3名病人的随访观察表明 ,其各自体内毒株间的同源性分别为 92 .10 %～ 99.73% ,95 .36 %～ 97.5 4 %和 97.0 7%～ 99.2 0 %。结论　不同HCV毒株间高变区基因的变异相当大 ,但在同一个病人体内 ,同一株病毒在相对较短的时间里的变异却相当有限 ,其不同分离株间 1年内的变异 <7.9%。可运用这一特点在分子水平上对部分丙型肝炎的传播途径进行确认 ,排除某些明显的非输血途径感染的丙型肝炎。

Dynamic variation of HCV hypervariable region gene and homology analysis

Objective To find out the dynamic variation on HCV genome to give the theoretic basis for diagnosis of post transfusion hepatitis C,and demonstrate the causality between donors and recipients suffering from post transfusion hepatitis C.Methods The high variable envelope gene fragments (HVR1 and HVR2) of HCV was selected for a cross sectional study and a one year follow up study was carried out on 3 HCV patients at every 3 month period to understand the dynamic variation of HCV HVR in each patient.Results The homology of HCV HVR genes among different types is 56.99%～60.88%,65.09%～68.80% among different subtypes,and 80.05%～96.40% among the same subtypes.It consists with the geographic distribution of HCV.The homology between the different strains isolated from the same patients is 92.10%～99.73%,95.36%～97.54 and 97.07%～99.20%,respectively.Conclusion The variation of different HCV strains in HVR is great.However,the variation of the same virus in the same patient during short infectious period is rather limited,which is no more than 7.9% per year.So the transmission pathway of some hepatitis C cases can be trailed at the molecular level by this way,and some non transfusion transmitted hepatitis C cases can be exclude