陕西省MSM人群中HIV-1分子流行病学研究

Moleculo-epidemiological study on HIV type Ⅰ among MSM in Shaanxi Province

目的了解陕西省近年来发现的男男性行为人群(Men who have sex with men,MSM)中,艾滋病病毒(Human immunodeficiency virus,HIV)流行株的基因序列特征、亚型、流行现状和趋势,为艾滋病防治工作提供科学依据。方法对HIV感染者进行流行病学相关因素调查,无菌采集全血,分离血浆提取病毒核酸,应用套式反转录聚合酶链式反应(Nested reverse transcription-polymerase chain reaction,Nested RT-PCR)扩增gag、env和pol基因的部分片段,并对扩增产物进行测序,用Mega 5.0软件将测序结果与各亚型国际参考株比对,根据基因离散率和系统进化树分析确定基因型及其特征。结果 71份样本中成功获得51份PCR扩增阳性产物并得到相应序列。综合gag、env和pol基因离散程度和系统进化树分析发现,陕西省MSM人群中至少存在3种HIV-1基因亚型和重组毒株(即B亚型、CRF01_AE和CRF07_BC重组型)。其中CRF01_AE为主要流行株,共28例(54.9%),其次是CRF07_BC重组型20例(39.2%)和B亚型3例(5.9%),重组型占到了94.1%(48/51)。根据基因离散率,在三种不同基因片段中,以env基因变异程度最大,HIV-1B亚型、CRF07_BC和CRF01_AE重组型的组内离散率分别为(12.8%±1.2%)、(6.6%±0.6%)和(8.4%±0.7%)。结论首次在陕西省MSM人群HIV感染者中,发现至少存在HIV-1B亚型和CRF01_AE、CRF07_BC重组型,以CRF01_AE重组型为主。该人群显示多亚型且近期呈高度流行的趋势。加强对MSM人群的行为干预,控制HIV在MSM人群中的传播,将是今后陕西省艾滋病防治工作的重点之一。

Objective To study the characteristics of human immunodeficiency virus（HIV） gene sequence,subtype distribution and origin of HIV strains,as well as its epidemic status and trends among men who have sex with men（MSM） in Shaanxi Province,so as to provide scientific evidence for policy making and development of AIDS prevention and control measures.Methods Anticoagulating blood samples were collected from HIV infected individuals and epidemiological data were analyzed.The gag,env and pol gene were amplified by nested PCR from the RNA extraction and then sequenced.The acquired sequences were compared with the international subtype references.The phylogenetic trees were constructed to determine the subtype of the samples.Results Out of the 71 samples,51 samples were PCR positive and the sequences were acquired.Phylogenetic analysis revealed at least three varieties of HIV-1 subtypes and recombinants among local HIV infected MSM.Of them,28 cases were CRF01_AE（54.9%）,20 cases were CRF07_BC（39.2%） and 3 cases were subtype B.The proportion of the CRFs was 94.1%（48/51）.According to the genetic distances,maximum variation occurred with env.The genetic distances within group of subtype B,CRF07_BC and CRF01_AE were（12.8/%±1.2%）,（6.6%±0.6%） and（8.4%±0.7%）,respectively.Conclusion It is for the first time to identify subtype B,CRF01_AE and CRF07_BC among HIV infected MSM in Shaanxi Province.CRF01_AE is the dominant strain and shows a high prevalence.It is suggested that in the future AIDS prevention and control in this province,the emphasis should be placed on strengthening behavioral intervention and controling HIV transmission in the MSM population.