我国男男性行为人群中HIV-1病毒亚型分布及其演变

男男性行为人群(MSM)仍是我国HIV感染的高危人群,欧美B亚型、CRF01_AE和CRF07_BC亚型是其人群中流行的主要病毒亚型。近年来,MSM中HIV-1亚型的流行趋势发生改变,欧美B亚型所占比例显著下降,CRF01_AE和CRF07_BC亚型所占比例则明显增加,并且出现新的重组亚型。运用分子生物学技术分析我国男男性行为人群中HIV-1病毒亚型分布和变化趋势,可有助于阐明MSM人群中HIV-1的流行规律,追踪传染来源和确定相关危险因素,并为MSM人群精准干预提供重要的参考依据。     

The dynamic face of HIV-1 subtypes among men who have sex with men in Beijing, China

The rapid increase of HIV-1 prevalence among Chinese men who have sex with men (MSM) provides an impetus for the acquisition of molecular epidemiologic information from this population. We conducted four serial cross-sectional surveys during year 2005-2009 and observed that the composition of HIV-1 subtypes was dynamically changing with from clade B to CRF01_AE from years 2005-2009. HIV-1 infection in this population includes the persistent circulation of multiple HIV-1 subtypes and complex new recombinants.     

The changing molecular epidemiology of HIV type 1 among northern Thai drug users, 1999 to 2002

CRF01_AE and subtype B have dominated the HIV-1 epidemic in Thailand since 1989. We reported a new circulating recombinant form of HIV-1, CRF15_01B, as well as other unique CRF01_AE/B recombinants among prevalent HIV infections in Thailand. We sought to study this challenging molecular picture through assessment of subtypes among recent HIV-1 seroconverters in northern Thai drug users. A total of 847 HIV-1 seronegative drug users (342 IDU and 505 non-IDU) were enrolled, from 1999 to 2002, in a prospective study; 39 HIV-1 incident cases were identified and characteristics were collected. The overall HIV-1 incidence rate was 2.54/100PY, but it was 10.0/100PY among male IDU. HIV was strongly associated with injection history; 38 of 39 seroconverters gave a history of IDU. A near full-length genome of HIV-1 was recovered by PCR amplification and sequenced from peripheral mononuclear cell extracted DNA of 38 seroconverters. Phylogenetic analysis revealed that 33 (86.8%) were CRF01_AE and 5 (13.2%) were CRF01_AE/B recombinants. These recombinants had different structure but shared some common breakpoints, indicating an ongoing recombination process. Recombinant infection increased with year of sampling (0 to 57.1%). The molecular epidemiology of HIV-1 among drug users in northern Thailand has thus entered a new era. CRF01_AE remains predominant while pure subtype B is becoming rare, and now a substantial component of the epidemic. These findings support the need for CRF01_AE and subtype B components in clade-matched vaccine strategies for Thai phase III trials. Ongoing molecular surveillance of circulating HIV-1 strains is imperative for the evaluation of HIV vaccine efficacy.     

Identification of subtype B, multiple circulating recombinant forms and unique recombinants of HIV type 1 in an MSM cohort in China

To study HIV-1 genetic diversity among HIV-positive men who have sex with men (MSM) in China, a cohort consisting of HIV-positive MSM was established in 2005 and was monitored every 2 years. In 2007, 44 HIVpositiveMSM subjects were genotyped, and the results showed HIV-1 subtype B decreased from 77.5% to41.9%, but non-B subtypes increased rapidly represented by CRF01_AE from 3.7% to 30.2% compared to 2005.In addition, one case of CRF07_BC was first identified in this population, which mainly circulated among HIV-1-infected injection drug users (IDUs) in China. There were 11 unique recombinant forms (URFs) consisting ofa recombination of CRF01_AE with subtype B or CRF07_BC. The subtype-specific phylogenic tree analysis showed that the genetic distance within subtype B group viruses was larger than the genetic distance within the CRF01_AE group (p 0.001). Of the identified viruses in the Chinese MSM population, over 80% of subtype B viruses might originate from the United States and Brazil, and over 85% of the CRF01_AE viruses mightoriginate from Thailand. In addition, epidemic study data showed that some of the HIV-1-infected MSM had foreign sexual partners (13.6%) and heterosexual activities (43.2%). The patients infected with HIV-1 URF viruses had more heterosexual encounters (54.5%) and more sexual partners (72.7%) compared to those infected with subtype B (44.4%; 33.3%) and CRF01_AE (23.1%; 69.2%) viruses. Taken together, we suspected that the genetic complexity of HIV-1 viruses identified in Chinese MSM populations was more likely a result of multiple introductions of viruses from the general population infected with HIV-1 through IDUs or heterosexual transmission.     

MSM人群急性HIV-1感染者病毒亚型分析

目的研究2007-2009年男男性行为人群（MSM）艾滋病病毒-1型（HIV-1）的基因亚型,以监测MSM人群HIV病毒株的最新流行情况。方法采集95例MSM急性HIV-1感染者的外周全血,从外周全血浓缩白细胞中提取脱氧核糖核酸（DNA）,用巢式聚合酶链反应（Nested-PCR）对HIV-1的前病毒DNA进行扩增,然后检测并分析PCR扩增产物的核苷酸序列,确定病毒的基因亚型。结果 95例感染者平均年龄为（35.02±9.15）岁,其中20～50岁的青壮年45例（94.74%）,未婚51例（53.68%）,大专或大学及以上文化程度者30例（占31.58%）。感染者中共发现CRF01_AE亚型、B亚型、BC重组亚型（包括CRF07_BC和CRF08_BC）及C亚型4种亚型。其中CRF01_AE重组亚型56例（占58.95%）,B亚型28例（占29.47%）,BC重组亚型10例（占10.53%）,C亚型1例（1.05%）。结论 MSM人群急性HIV-1感染者年轻化,文化程度普遍偏低。小样本流行病学调查显示,急性HIV-1感染者中有CRF01_AE亚型、B亚型、BC重组亚型及C亚型4种亚型病毒株流行,CRF01_AE亚型为MSM人群的主要亚型。     

Multiple introductions of HIV into men who have sex with men were found in Zhengzhou City, China

Zhengzhou is the capital of Henan province, where severe HIV prevalence was found in former paid plasma donors. In recent years, the HIV epidemic in men who have sex with men (MSM) increased rapidly in the city. To explore the subtype distribution and genetic characterization of HIV in MSM in Zhengzhou city, phylogenetic analysis was fulfilled based on the full-length gag, pol, and partial env gene. A total of 31 HIV-1-seropositive MSM individuals were enrolled. The full length gag, pol, and partial env gene were amplified and sequenced. Multiple subtypes, including CRF01_AE (45.2%), subtype B (38.7%), and CRF07_BC (16.1%), were identified. Close phylogenetic relationships among our strains with strains from the Henan local area, Hebei MSM population, Beijing area, and Liaoning area were found, suggesting a multiple introduction of HIV into the population. The results will provide clues for prevention and for changes in behavior in the Henan MSM population and also detailed sequence data for vaccine design.     

Identification of new CRF51_01B in Singapore using full genome analysis of three HIV type 1 isolates

A recent HIV-1 molecular epidemiology survey in Singapore identified a novel CRF01_AE/B recombinant form, which accounted for 13 (11.9%) of 109 patient samples. Peripheral blood mononuclear cell DNA from three of these 13 patients was used to generate near full-length sequences to characterize the novel CRF01_AE/B recombinant form. The three isolates had a recombinant structure composed of CRF01_AE and subtype B, and shared identical breakpoints. As the three patients were not epidemiologically linked, this recombinant form has been designated CRF51_01B. Identification of the novel recombinant forms indicates ongoing active HIV-1 transmission in Singapore.     

Genetic characterization of CRF01_AE full-length human immunodeficiency virus type 1 sequences from Fujian, China

HIV-1 CRF01_AE is the main prevalent HIV-1 recombinant strain in China and the dominant strain in Fujian as well; therefore, obtaining and understanding the genetic characterization of this clade become important. To date only a few full-length HIV-1 CRF01_AE genomes from China have been sequenced. We reported 13 full-length HIV-1 CRF01_AE isolate sequences from Fujian, China. DNA was extracted, the 5' and 3' halves of each genome were separately amplified, and the PCR products were cloned and sequenced. The phylogenetic analysis of the 13 sequences showed that they clustered with HIV-1 CRF01_AE isolates; these isolates were separated into a few distinct subgroups and were dispersed among the Thailand isolates, and the intersample diversity among Fujian isolates was significantly high. The high gene diversity among Fujian HIV-1 CRF01_AE isolates indicates that the HIV-1 CRF01_AE viruses in Fujian may be transmitted from multiple introductions. The work is essential for the design and development of an effective AIDS vaccine for China.     

Molecular epidemiology of HIV Type 1 in preparation for a Phase III prime-boost vaccine trial in Thailand and a new approach to HIV Type 1 genotyping

To characterize HIV-1 genotypes in candidate populations for a prime-boost phase III vaccine trial in Thailand, specimens from prevalent and incident HIV-1 infections from a family planning clinic population in Rayong Province and a community cohort in Chon Buri Province, collected from 1998 to 2001, were genotyped. A new multiregion hybridization assay, MHAbce, capable of distinguishing HIV-1 CRF01_AE, subtype B, and subtype C and their recombinants, was developed and applied to prevalent infections. Most incident and selected prevalent infections were studied by complete genome sequencing. By MHAbce, 168 of 194 prevalent infections were genotyped. Of these, 90.5% were CRF01_AE, 2.4% were subtype B, and 7.2% showed discordant or dual probe reactivity, indicative of recombination or dual infection, respectively. Among 23 incident infections, 20 were sequenced. Eighteen CRF01_AE, one subtype B, and one CRF01/B recombinant strains were seen. Two CRF01/B and one CRF01/C recombinant were identified among selected prevalent infections. These results indicate that incident and prevalent HIV-1 infections in Rayong and Chon Buri during 1998-2001 were 90% CRF01_AE, 3% subtype B, and 7% either recombinant or dual. This study frames the genetic diversity of HIV-1 in these cohorts in their preparatory phase for the ongoing ALVACHIV (vCP1521) prime, AIDSVAX B/E boost, phase III vaccine trial and will provide a benchmark for interpretation and analysis.     

Impact of HIV-1 CRF55_01B infection on CD4 counts and viral load in men who have sex with men naive to antiretroviral treatment

Background

CRF55_01B, a newly identified HIV-1 circulating recombinant form (CRF) with a backbone of CRF01_AE, originated from men who have sex with men (MSM) and can be traced back to 2005 in Shenzhen, China. Circulating primarily among MSM, it has now spread throughout most provinces of China with a prevalence ranging from 1·5% to 12·5%. However, its impact on the progression of disease has not been investigated.

Maintaining low HIV type 1 env genetic diversity among injection drug users infected with a B/C recombinant and CRF01_AE HIV type 1 in southern China

HIV-1 outbreaks in Guangxi Province, southern China were initiated from two separate border cities in 1996 and 1997. Drug users in Pingxiang City, which borders Vietnam, were infected with CRF01_AE HIV-1, and drug users in Baise City, which borders Yunan Province, were infected with a novel B/C recombinant HIV-1. Since 1997, HIV-1 has been rapidly spreading in Guangxi, including its capital city Nanning. Survey data indicated that HIV-1 prevalence among IDUs in new outbreak regions increased 8 to 42% within 1 year. The B/C recombinants obtained from five separate regions in Guangxi, which span a 4-year time frame, were remarkable for their low intersubject env V3 diversity, less than 0.2%. Similarly, the CRF01_AE from IDUs over a 3-year time frame had low intersubject env V3 diversity of less than 1.6%. Different patterns of sequence variations in the V3 and V4 regions were observed for the B/C recombinant and the CRF01_AE HIV1. The rapid spreading of homogeneous HIV-1 strains in Guangxi may have important implications for HIV transmission as well as vaccine development and evaluation.     

Emergence of new forms of human immunodeficiency virus type 1 intersubtype recombinants in central Myanmar

We have previously shown that HIV-1 env subtypes B' (a Thai-B cluster within subtype B) and E (CRF01_AE) are distributed in Yangon, the capital city of Myanmar. However, HIV strains from the rest of country have not yet been genetically characterized. In the present study, we determined env (C2/V3) and gag (p17) subtypes of 25 specimens from central Myanmar (Mandalay). Phylogenetic analyses identified 5 subtype C (20%), in addition to 10 CRF01_AE (40%) and 4 subtype B' (16%). Interestingly, the remaining six specimens (24%) showed discordance between gag and env subtypes; three gag subtype B'/env subtype C, one gag subtype B'/env subtype E, one gag subtype C/env subtype B', and one gag subtype C/env subtype E. These discordant specimens were found frequently among injecting drug users (4 of 12, 33%) and female commercial sex workers (2 of 8, 25%) engaging in high-risk behaviors. The recombinant nature of these HIV-1 strains was verified in three specimens, indicating the presence of new forms of HIV-1 intersubtype C/B' and C/B'/E recombinants with different recombination breakpoints. The data suggest that multiple subtypes of B', C, and CRF01_AE are cocirculating in central Myanmar, leading to the evolution of new forms of intersubtype recombinants among the risk populations exhibiting one of the highest HIV infection rates in the region.     

福建省MSM哨点监测HIV新近感染影响因素及分子流行特征研究

目的 了解福建省MSM人群HIV新近感染状况,探讨其分子流行特征和相关影响因素,为制定艾滋病防治策略提供科学依据。方法 对福建省2019年MSM哨点监测人群HIV抗体阳性样本采用HIV-1限制性抗原亲和力酶联免疫法(简称LAg-Avidity EIA)进行新近感染检测,用多因素Logistic回归分析其影响因素,通过RT-PCR扩增pol和gag区,利用系统进化树和HIV db Program 软件对序列进行基因亚型和耐药突变分析。结果 福建省2019年哨点监测MSM人群863人,其中总的HIV抗体阳性率为12.17%(105/863), HIV新近感染率为11.97%;Logistic回归分析显示,样本来源和最近6个月内同性肛交安全套使用频率是新近感染的影响因素;基因亚型以CRF07_BC(47.61%)和CRF01_AE(38.10%)为主,其次为CRF55-01B(9.52%)、B亚型(4.76%);HIV-1耐药率为6.67%(1/15),其中15例对蛋白酶类抑制剂、核苷类逆转录抑制剂均敏感; 1例对非核苷类逆转录酶抑制剂efavirenz (EFV)和nevirapine (NVP)产生高度耐药, 1例为潜在耐药。结论 福建省2019年哨点监测MSM人群HIV新近感染率处于较高水平,多种亚型并存,发现原发耐药株传播,应加强对HIV新近感染者的分子流行特征变化趋势以及原发耐药传播的动态监测,及时调整防控策略,有效控制福建省艾滋病感染与传播。     

Circulating recombinant form (CRF) 37_cpx: an old strain in Cameroon composed of diverse, genetically distant lineages of subtypes A and G

HIV-1 in Cameroon is genetically diverse, but is predominated by the circulating recombinant form (CRF) 02_AG, which cocirculates among an array of other CRFs, unique recombinant forms (URFs), and all group M subtypes. In particular, our studies of HIV-1 diversity in the East Province found a high proportion of URFs and second generation recombinants (SGRs), suggesting this region of Cameroon may be a breading ground for new CRFs. Herein we present the full-length sequence analysis of one such CRF, composed primarily (66%) of unique, distant lineages of subtypes A and G in alternating regions throughout the genome. This CRF also combines segments in pol and env genes possessing intrasubtype distance (<15%) to the CRF01_AE and CRF02_AG radiations. The genomic composition of this strain comprising gene segments of subtypes A and G as well as CRF01_AE and CRF02_AG defines this strain as a circulating SGR (CSGR), and the 37th CRF to be identified. Furthermore, more than half of CRF19_cpx, a CRF identified in Cuba, clusters with CRF37_cpx, and the clear genetic distance among the viruses in this cluster suggests this strain has been in circulation since the early days of the epidemic. The genetically distant segments comprising CRF37_cpx, which were found to cluster outside the crown groups of previously described viruses, may represent a link to very rare or extinct strains, and, potentially, to understanding the evolutionary history of HIV-1 in this region.     

Identification of CRF34_01B, a second circulating recombinant form unrelated to and more complex than CRF15_01B, among injecting drug users in northern Thailand

In Thailand, the circulating HIV-1 strains include CRF01_AE, subtype B, and their recombinants. Genotyping and full-genome sequencing had previously identified circulating recombinant form CRF15_01B within a cohort of 347 HIV-1-infected individuals enrolled in the Opiate Users Research (OUR) study in northern Thailand. Using an improved MHAbce in six to eight genome regions and archived OUR serum samples, seven strains were identified with a new and complex 01/B recombinant pattern in common, different from that of CRF15_01B. Complete sequencing of three strains, amplified from serum as overlapping half-genomes, confirmed their common recombinant structure, mostly CRF01_AE, but with segments of subtype B in pol and gp41, plus a region of frequent 01/B crossovers in pol. OUR strains 1969P, 2275P, and 2478P were from individuals without direct epidemiological linkage and thus establish CRF34_01B. More comprehensive HIV-1 prevention and treatment programs in IDU can help to limit the growing complexity of HIV-1 strains in Thailand.