K65R in Subtype C HIV-1 Isolates from Patients Failing on a First-Line Regimen Including d4T or AZT: Comparison of Sanger and UDP Sequencing Data

BACKGROUND: We and others have shown that subtype C HIV-1 isolates from patients failing on a regimen containing stavudine (d4T) or zidovudine (AZT) exhibit thymidine-associated mutations (TAMs) and K65R which can impair the efficacy of Tenofovir (TDF) at second line. Depending on the various studies, the prevalence of K65R substitution as determined by the Sanger method ranges from 4 to 30%. Our aim was to determine whether ultra-deep pyrosequencing (UDPS) could provide more information than the Sanger method about selection of K65R in this population of patients. METHODS: 27 subtype C HIV-1 isolates from treated patients failing on a regimen with d4T or AZT plus lamivudine (3TC) plus nevirapine (NVP) or efavirenz (EFV) and who had been sequenced by Sanger were investigated by UDPS at codon 65 of the reverse transcriptase (RT). 18 isolates from naïve patients and dilutions of a control K65R plasmid were analysed by Sanger plus UDPS. RESULTS: Analysis of Sanger sequences of subtype C HIV-1 isolates from naïve patients exhibited expected polymorphic substitutions compared to subtype B but no drug resistance mutations (DRMs). Quantitation of K65R variants by UDPS ranged from <0.4% to 3.08%. Sanger sequences of viral isolates from patients at failure of d4T or AZT plus 3TC plus NVP or EFV showed numerous DRMs to nucleoside reverse transcriptase inhibitors (NRTIs) including M184V, thymidine-associated mutations (TAMs) plus DRMs to non- nucleoside reverse transcriptase inhibitors (NNRTIs). Two K65R were observed by Sanger in this series of 27 samples with UDPS percentages of 27 and 87%. Other samples without K65R by Sanger exhibited quantities of K65R variants ranging from <0.4% to 0.80%, which were below the values observed in isolates from naïve patients. CONCLUSIONS: While Sanger sequencing of subtype C isolates from treated patients at failure of d4T or AZT plus 3TC plus NVP or EFV exhibited numerous mutations including TAMs and 8% K65R, UDPS quantitation of K65R variants in the same series did not provide any more information than Sanger

Detection of low-frequency HIV type 1 reverse transcriptase drug resistance mutations by ultradeep sequencing in naive HIV type 1-infected individuals.

International audienceGenotypic resistance testing is recommended to evaluate the susceptibility of HIV to antiretroviral drugs. These tests are based on bulk population sequencing and thus consider only variants representing more than 20% of the viral population, whereas next generation sequencing methods allow detection below this threshold. We aimed to evaluate the potential use of ultradeep pyrosequencing (UDPS) for genotypic resistance testing in clinical routine at the University Hospital of Bordeaux, France. We performed UDPS on reverse transcriptase (RT) from 47 HIV-1 individuals, naive of antiretroviral treatment and for whom genotypic resistance testing was requested for clinical management in 2011-2012. In 8.5% of the patients, only low-frequency variants harboring RT drug resistance mutations were detected raising the question of their clinical significance. Rilpivirine-associated resistance mutations were detected in 19.1% of our population study. To conclude, UDPS could become a routine tool for the evaluation of HIV-infected patients in hospital laboratories

Comparison of Sanger and UDPS sequencing results for RT codons 65 and 70; same isolates as in Table 3.

<p>Sanger Y: presence of mutation; N: absence of mutation. UDPS: Frequency of mutations observed in samples.</p

Resistance mutations and CTL epitopes in archived HIV-1 DNA of patients on antiviral treatment: toward a new concept of vaccine.

International audienceEleven patients responding successfully to first-line antiretroviral therapy (ART) were investigated for proviral drug resistance mutations (DRMs) in RT by ultra-deep pyrosequencing (UDPS). After molecular typing of the class I alleles A and B, the CTL epitopes in the Gag, Nef and Pol regions of the provirus were sequenced and compared to the reference HXB2 HIV-1 epitopes. They were then matched with the HLA alleles with determination of theoretical affinity (TA). For 3 patients, the results could be compared with an RNA sample of the circulating virus at initiation of therapy. Five out of 11 patients exhibited DRMs by UDPS. The issue is whether a therapeutic switch is relevant in these patients by taking into account the identity of the archived resistance mutations. When the archived CTL epitopes were determined on the basis of the HLA alleles, different patterns were observed. Some epitopes were identical to those reported for the reference with the same TA, while others were mutated with a decrease in TA. In 2 cases, an epitope was observed as a combination of subpopulations at entry and was retrieved as a single population with lower TA at success. With regard to immunological stimulation and given the variability of the archived CTL epitopes, we propose a new concept of curative vaccine based on identification of HIV-1 CTL epitopes after prior sequencing of proviral DNA and matching with HLA class I alleles

RT bulk sequences of 27 subtype C HIV-1 isolates failing on first line.

<p>DRMs are noted according to ANRS.</p

Primers used for GS Junior ultradeep sequencing of RT.

<p>Primers used for GS Junior ultradeep sequencing of RT.</p

Phylogenetic trees of UDPS sequences (Pol RT2) at baseline and at ART success.

<p>Patients D, B and F according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069029#pone-0069029-t001" target="_blank">Table 1</a>.</p

Potential CTL reactivity against viral (RNA) and/or archived proviral DNA epitopes according to HLA I alleles.

<p>After characterization of HLA alleles, we investigated the CTL epitopes that should be recognized by the patients and have determined the affinity through the MHC IC 50 values. The reference epitopes are from the HXB2 reference. Whether identical or variant, the epitopes were noted in the circulating virus at baseline (RNA) and/or the archived proviral DNA at therapeutic success.</p

Dynamic and rapid changes in viral quasispecies by UDPS in chronic hepatitis C patients receiving telaprevir-based therapy

International audienceBackground: Telaprevir (TVR) is a protease inhibitor (PI) used in chronic hepatitis C treatment with pegylated interferon plus ribavirin. We analysed the prevalence and kinetic development of TVR resistance upon treatment.Methods: A total of 24 cirrhotic patients (genotype 1a, n=8; genotype 1b, n=16) previously non-responders to standard therapy were treated with TVR-based therapy. The distribution of TVR-resistant variants was assessed at every HCV-RNA-positive time point by 454 ultra-deep pyrosequencing (UDPS) during a mean follow-up period of 9.4 months.Results: A median of 6,837 reads/specimen was studied. Based on control UDPS, we considered mutations as real when present >0.4%. TVR-resistant variants were found at baseline in 8/24 patients (33.3%). Four of the 24 patients (16.7%), all genotype 1a, did not achieve HCV RNA20%), did not always preclude TVR treatment success. The detection of R155K/T/Q at baseline may predict failure in genotype 1a patients. At failure, which occurred in genotype 1a patients, a significant enrichment in V36A/M and R155K/T/Q was observed

Primers used for Gag, Nef and Pol amplification.

<p>Primers used for Gag, Nef and Pol amplification.</p