The Profile Of The HIV-1 Drug Resistance In Patients With Virologic Failure And The Impact Of HIV-1 Quasispecies With Drug Resistance Mutations On HIV-1 Adaptability In China

Since 1990s,The introduction of highly active antiretroviral therapy (HAART) has dramatically minimized morbidity and mortality of HIV-1-infected individuals. Despite great advantage in antiretroviral therapy (ART), HAART cannot completely eradicate HIV from the body, results in long-term toxicity and eventually leads to the emergence of drug-resistant HIV strains among ARV-experienced patients under the drug pressure in vivo, which was considered a major cause of treatment failure. HIV-1 genotypic drug resistance testing is an effective tool for the surveillance of HIV-1 drug resistant strains.HIV-1 genome differs by 10% to 30% between subtypes of M group. Amino acid sequence diversity in the pol gene is 10% to 15% between different subtypes, which may influence the pattern of drug resistance in different subtypes. Increasing evidence suggests that as the diverse degree of genetic diversity of HIV-1, HIV subtypes and CRFs probably evlove in different pattern and frequencies when they are under selective pressure of specific drugs. Globally, specific subtypes and CRFs are found more frequently in certain countries or regions of the world. While subtype B predominates in developed countries of Western Europe and U.S., other (non-B) subtypes or CRFs account for the majority of infections in the developing world. To date, however, scarce data are available on the impact of ARV in HIV-1 of non-B subtypes, which paradoxically account for almost 90% of all HIV infections in the world. Subtype B, CRF01_AE and CRF07_BC are prevailing in China but of little information is available on the profile of non-B subtypes HIV-1 drug resistance in patients with virologic failure to date. It becomes more and more important to study resistance-associated genetic characteristic of subtype B, CRF01_AE and CRF07_BC isolates and evaluate the the profile of the HIV-1 Drug resistance in patients with virologic failure. In our research, we analyzed the drug resistance mutations of RT gene in 211 HIV-1 subtype B',77 CRF07_BC and 58 CRF01_AE isolates from treatment-experienced patients in Henan, Anhui, Sichuan, Guangxi, Yunnan, Xinjiang, Hunan, Zhejiang Shandong and Guangdong provinces along the 346 amino acid sequence in the HIV-1 pol gene. We evaluated HIV-1 genotypic diversity and the prevalence of primary ARV resistance mutations associated with RT inhibitors among patients with VF which can represent the China widespread AIDS patients with VF. The overall frequency analysis showed that the 3 most prevalent mutations after ART in China in the RT coding region were the lamivudine(3TC)-specific mutation M184VI, the zidovudine(AZT)-specific mutation T215YF, M41L were the 3 most prevalent drug resistance mutations after ART in China associated with the NRTI therapy while K103N, Y181C, and G190A were the 3 most prevalent NNRTI resistance-associated mutations.. We found that the frequency of the mutations in the studied samples were different especially in the RT level, between samples belonging to divert subtypes circulating in China (B', CRF07_BC or CRF01_AE). Our group has shown that for 3TC-based regiment exposure, the proportion of resistant strains (55.7% vs.34.2%; 67.8% vs.50.0%) and the average number of mutations per genome (1.270 vs.0.447; 1.330 vs.0.868) of NRTI and NNRTI were observed significantly lower in subtype CRF07 BC-infected patients compared to subtype B respectively. We observed different proportions of NRTI and NNRTI-associated drug resistance occurance at specific amino acid positions between subtypes when exposed to 3TC-based regiment. The thymidine analogue mutations M41L, T215YF, 3TC-associated mutation M184VI, the NNRTI-associated mutation Y181C occurred significantly higher in subtype B isolates compared to subtype CRF07_BC isolates (10.4% vs.1.3%; 48.7% vs.31.6%; 19.1% vs.1.3%; 26.1% vs.13.2%, respectively), and the thymidine analogue mutations D67N, K70ER were found significantly more frequent in subtype CRF01_AE than CRF07_BC isolates(14.3% vs.1.3%; 10.2% vs. 1.3%). When we further analyzed the different pattern of codons and their proportions of these resistance mutations, in generally there are no significant difference between subtypes. In summary, it is remarkable a lower rate of mutations conferring resistance to ARV in subtype CRF07_BC compared to subtype B. We have found that differences in the frequences of NRTI and NNRTI drug resistance-associated mutations present in the pol region of samples belonging to subtype B,CRF07_BC and CRF01_AE. Viruses from some subtypes may have a greater propensity to develop resistance against certain drugs than do other viral variants. Significant differences between subtypes circulating in China may be associated with the development of diverse resitance patterns after ART therapy may afterwards affect specific drug utility in patients infected with any of these subtypes. Two prospective cohorts were established in Henan and Anhui provinces, respectively. Patients recruited were those who initiated antiretroviral therapy (ART) at the beginning of Chinese national free ART program. So far, these patients have been followed up at six month intervals for six years. In this study, we aimed to explore the evolution of HIV-1 drug-resistant quasispecies, the changes of drug resistance mutation pattern and the inter-linkages between mutations by using single-genome sequencing method in patients from the cohorts. Four patients were selected; two of them had a persistent use of a earlier first line regiment, the other had a history of drug withdrawal and experienced a change of later first line regiment. A single mutation associated with NRTIs resistance emerged firstly couldn't exist at a long period and would be replaced by other multiple mutations. Mutations associated with NNRTIs resistance were relative stable and usually resulted in high resistance to NNRTIs. With longer therapy duration, the rate of HIV-1 resistant variants raised gradually. In the patients who had a history of drug withdrawal and experienced a change of later first line regiment, a single drug resistance mutation emerged firstly belong to the atypical drug resistance mutation and were replaced by increased proportion of multiple mutations. The pattern of drug resistance is stable and few in the patients who had a persistent use of a earlier first line regiment.The single mutation K103N were very stable for more than 24 months, the same as the following mutation patterns:K103N/Y181C, K101E/Y181C/G190A,K103N/V179F/Y181C, K101E/V108I/Y181C/G190A.Mutations such as mutations associated with NRTIs T215Y,M41L,M184V,L74I,L210W and mutations associated with NRTIs K103N, G190A, K101E,Y181C,V108I were detected by Single-genome sequencing method in advance of 6-53 months when compared with conventional drug resistance genotypic assay.