Laboratoire associé au CNR du VIH, hôpital Ch. Nicolle, CHU de Rouen, France.
AIDS. 2011 Jul 17;25(11):1371-7. doi: 10.1097/QAD.0b013e328347c060.
HIV-1 group M is characterized by substantial genetic diversity, and includes nine subtypes, more than 45 circulating recombinant forms (CRFs), and numerous unique recombinant forms (URFs). In France, the epidemic is characterized by predominance of subtype B strains, increasing prevalence of non-B subtypes (CRF02_AG being the most prevalent) and increasing at-risk behaviour in the MSM population. The high prevalence and co-circulation of B and CRF02_AG strains in this population raise the possibility that recombinant forms might emerge and spread.
Samples from seven patients (five being MSM) were selected on the basis of subtyping discordances in different regions. The pattern of each near full-length genome of the viruses was characterized. The relationships between the newly and previously described B/CRF02_AG URFs were analysed using phylogenetic networks. Single genome amplification was used to search for the parental strains and confirmation of the breakpoints.
Seven unique recombination patterns were identified, breakpoints being found throughout the genomes, with hotspots in pol and accessory genes. No link was observed with the previous forms, but the CRF02 regions of two new viruses indicated that they are phylogenetically associated, suggesting a common ancestral strain. No evidence of circulating parental strains was found.
This description of seven URFs involving subtype B and CRF02_AG highlights the growing complexity of HIV molecular epidemiology in France. These multiple patterns, found mostly in MSM, and the hypothesis of a better fitness of some recombinant strains, argue for a context that could lead to the genesis of CRFB/02_AG strains in France.
HIV-1 组 M 的特点是具有大量遗传多样性，包括 9 个亚型、超过 45 种循环重组形式（CRF）和许多独特重组形式（URF）。在法国，流行的特点是 B 亚型株的优势、非 B 亚型（CRF02_AG 是最流行的）的流行率增加以及男男性行为者人群中风险行为的增加。在该人群中，B 和 CRF02_AG 株的高流行率和共同流行增加了重组形式可能出现和传播的可能性。
根据不同地区的亚型分型差异，选择了来自七名患者（五名是男男性行为者）的样本。对病毒的每个近全长基因组的模式进行了特征描述。使用系统发育网络分析了新描述的 B/CRF02_AG URF 与之前描述的 URF 之间的关系。使用单基因组扩增来搜索亲本株，并确认断点。
确定了七种独特的重组模式，断点在整个基因组中都有发现，在 pol 和辅助基因中存在热点。没有观察到与之前的形式有关联，但两个新病毒的 CRF02 区域表明它们在系统发育上有关联，提示存在共同的祖先株。没有发现循环亲本株的证据。
本研究描述了涉及 B 亚型和 CRF02_AG 的七种 URF，突出了法国 HIV 分子流行病学日益复杂的情况。这些主要在男男性行为者中发现的多种模式，以及一些重组株具有更好适应性的假设，表明了可能导致法国出现 CRFB/02_AG 株的背景。
