A Molecular Epidemiological Study On HIV-1 Subtypes And Drug-resistance Gene Mutation

Background and Objective:Currently, HIV-1 prevalent strains have evolved into complicated subtypes in China. There is also significant variation in HIV-1 subtype distribution between time periods, regions and populations in China. The previous studies showed HIV-1 subtypes were possibly related to disease progression and drug resistance mutation. In China, the prevalence mode of HIV transmission has a big change. The scale of antiretroviral therapy ?ART? is also constantly expanding. Therefore, a comprehensive investigation of HIV-1 subtype and drug resistance mutation is necessary to reveal HIV epidemic and predict the trend of HIV prevalence. Currently, sexual transmission has become the primary route of HTV transmission in China. A meta-analysis was conducted to understand the characteristic of different HIV-1 subtypes in sexual transmission in China. Under this precondition, a molecular epidemiological survey was conducted in order to understand the distribution characteristics of HIV-1 subtype and the prevalence of HTV-1 drug resistance ?DR? mutations among HTV-1/AIDS patients in Wuxi city. What's more, relevant information of epidemiological investigation and HTV subtypes were included for multi-factor analyses to explore the potential influence factors that might affect AIDS disease progression and drug-resistance. The main objective of this study was to provide valuable information for preventing and treating AIDS in Wuxi city.Methods:1. Meta-analysis:We conducted a systematic literature review for studies of HIV-1 subtypes in English and Chinese through several databases. Eligible articles were screened and selected based on the inclusion and exclusion criteria by two authors independently. Random-effects model were applied to calculate the pooled prevalence of different HIV-1 subtypes, and subgroup analyses examined prevalence estimates across time, locations, and populations. All meta-analyses were performed using R software ?version 3.2.1? and SAS ?version 9.3, SAS Institute Inc., USA?.2. Analysis of HIV-1 sutypes:343 subjects were enrolled from the local HIV/AIDS routine monitoring cohort in Wuxi City between Oct 2012 and Jun 2013. Epidemiological case investigation and blood sample collection were conducted on the basis of informed consent. After partial env and pol gene amplified and sequenced, the acquired genetic fragment sequences were edited and analyzed to validate HIV-1 subtype and further analyze the distribution characteristics of HIV-1 subtype.3. Analysis of HIV-1 drug resistance ?DR? mutations:279 pol sequences were submitted to HIV drug resistance database to infer drug-resistance mutations ?DRMs? profile and antiretroviral susceptibility using Calibrated Population Resistance tool. ?http://hivdb.stanford.edu?.4. Statistical analysis:Using excel to establish database and SPSS 19.0 or SAS 9.3 software to analyze the data. Qualitative data were described with rate or proportion and analyzed with Chisquare test or fisher's exact test or Kruskal-Wallis test. Quantitative data were described with means and standard. The influence factors of HIV disease progression and drug-resistance were analyzed with repeated measurement data analysis, multivariate Logistic regression analyses or survival analyses.Results:1. A total of 130 eligible studies were identified, including 18752 successfully genotyped samples. The pooled prevalence of CRF01_AE, subtype B, CRF07_BC, CRF08_BC, and subtype C were 44.54%?95% CI 40.81-48.30?,18.31%?95% CI 14-71-22.17?,16.45%?95% CI 13.82-19.25?,2.55%?95%CI 1.56-3.73?,0.37%?95%CI 0.11-0.72?, respectively. The prevalence of subtype B in sexual transmission decreased, while the prevalence of CRF01_AE and CRF07_BC in sexual transmission, and CRF08_BC in heterosexual transmission increased. There is significant variation in HIV-1 subtype distribution between regions.2. Eventually,313 out of the 343 HIV/AIDS patients were successfully genotyped. Among 313 successfully genotyped, CRF01_AE accounted for the highest proportion of 49.4% ?n=155?, CRF07_BC for 16.9%?n=53?, B for 12.8%?n=40??CRF08_BC for 9.3%?n=29?, CRF67₀1B for 3.8%?n=12?, CRF68₀1B for 1.9%?n=6?, CRF02_AG for 0.3%?n=1?, CRF59₀1B for 0.3%?n=1?, C for 0.3%?n=1? and URFs for 4.8%?n=15?. There is significant variation in HIV-1 subtype distribution between sexes, ages and routes of transmission ?P<0.01?.3. DR-related mutations were identified in 36 of the 279 viral sequences ?12.9%?. Among drug-naive and treated individuals, the rate of HIV-1 drug resistance was 1.8%?4/220? and 16.9 ?19/59?, respectively. The major DR-related mutations caused high-level resistance and/or intermediate-level resistance, including D30N, L90M, K65R, M184IV, K103N and Y181C. The others caused potential low-level resistance and/or low-level resistance.4. CRF07/08_BC strains infection shows a slower disease progression compared with the subtype B ?OR=0.312,95%CI:0.134?0.728? through analyzing the influence factors of HIV-1 disease progression. However, it shows the opposite trend after CRF07/08_BC strains infection with drug resistance mutations ?OR=12.276,95%CI:2.255?66.830?. The results showed that ages was the protective factor for drug resistance ?OR=0.930,95%CI: 0.909?0.987? through analyzing the the influence factors of HIV-1 drug resistance.Conclusion:1. The distribution of HIV-1 subtypes and circulating recombinant forms have changed significantly in sexual transmission in China. The high genetic variability of HIV-1 poses a significant challenge for disease control and surveillance.2. Currently, HIV-1 pandemic strains were diverse and complicated in Wuxi city. Further strengthening health education and behavior intervention in different risk groups and close monitoring the dynamic changes of the HIV-1 subtype were necessary for the prevention and control of the emergence of new recombinant strains.3. Relative to subtype B, CRF07/08_BC infection has a slower disease progression. However, it shows the opposite trend after CRF07/08_BC strains infection with drug resistance mutations. The further studies are necessary for explore mechanism.4. Currently, the HIV-1 drug resistant strains transmission was at low prevalence level in Wuxi city. The main causation which leaded to DR-relate mutations was drug-induced mutation. However, cross resistance and transmission of HIV-1 DR strains suggested that DR surveillance should be strictly performed.