Allele-specific real-time PCR testing for minor HIV-1 drug resistance mutations: assay preparation and application to reveal dynamic of mutations in vivo / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>It is very important for the clinical management to test for minor HIV-1 resistance mutations accurately and sensitively. The conventional genotypic assays of HIV drug resistance detection based on sequencing can only discriminate the mutations which present in more than 20% - 30%. The aim of this study was to evaluate allele-specific real-time PCR (ASPCR) to detect the resistance-related mutations located at positions 103, 184 and 215.</p><p><b>METHODS</b>We developed the allele-specific PCR assay, using the most common drug resistance mutations in Chinese AIDS patients, K103N, M184V/I, T215F/Y as a model system. The standards were constructed by cloning the wild-type and mutant DNA fragments into the T-vector. We designed specific primers to discriminate mutant templates in the real-time PCR using SYBR green as a fluorescence reporter. And then we evaluated the ASPCR assay and tested 140 clinical samples using this method.</p><p><b>RESULTS</b>The sensitivities of ASPCR assay were 0.04% for K103N, 0.30% for M184I, 0.40% for M184V, 0.03% for T215F and 0.02% for T215Y. The intra-assay and inter-assay coefficients of variation were less than 0.42. One hundred and forty plasma samples were tested by ASPCR and dynamic resistance curves of ten patients were obtained.</p><p><b>CONCLUSIONS</b>Drug resistance emerged half a year after the start of antiretroviral therapy. The mutation of T215Y emerged 1 to 1.5 years after starting treatment and then increased rapidly. The ASPCR assay we developed was a sensitive, accurate and rapid method to detect the minor HIV-1 variants and it can provide earlier and more drug-resistance information for HIV research and AIDS antiretroviral therapy.</p>

Research on the selective kinetics of HIV-1 nucleoside reverse transcriptase inhibitor drug resistance-associated mutations among 4 AIDS patients receiving highly active antiretroviral therapy / 中华流行病学杂志

<p><b>OBJECTIVE</b>To elucidate the molecular evolutional characteristics of HIV-1 nucleoside reverse transcriptase inhibitor (NRTI) drug resistance-associated mutations in patients with AIDS receiving highly active antiretroviral therapy.</p><p><b>METHODS</b>We selected 4 AIDS patients receiving highly active antiretroviral therapy (HAART) with good adherence under a HIV-1 drug resistance cohort from a rural region in central China. Those people carried susceptible virus at the beginning of treatment and gradually came to produce virus resistant to NRTIs during the process of antiretroviral therapy (ART). Reverse transcriptase (RT) genes from each patient's peripheral blood samples (from 3 to 33 months after withdrawal) were cloned and sequenced in succession.</p><p><b>RESULTS</b>We sequenced a total number of 855 clones and obtained the HIV-1 NRTI drug resistance-associated mutations patterns of the 4 patients. Typical resistance mutations of thymidine analogue mutations (TAMs) pattern 1, such as L210W, T215Y and M41L, were generated in patient 'A'. TAMs pattern 2, including D67N, K70R and K219Q mutations, was discovered in patient 'B'. Interestingly, in patient 'C', some clones comprising not only TAMs pattern 1 mutations (T215Y) but also TAMs pattern 2 mutations (K70R, D67N).</p><p><b>CONCLUSION</b>The four patients show different pathways on HIV-1 NRTI drug resistance-associated mutations, including TAMs pattern 1, TAMs pattern 2 and the fusion pattern of TAMs-1 & TAMs-2. We also noticed that the tendency of gradual accumulation was obvious and those mutations detected earlier tended to be the predominant strains.</p>