Predictive value of gene mutations as a diagnostic tool for ART resistance in a Zambian population

[摘要] Background: While Selection of reverse transcriptase (RT) mutation has beenreported frequently, protease (PR) mutations on antiretroviral therapy (ART) includingboosted Protease inhibitor (PI) have not been reported as much in Zambia. Affordablein-house genotyping assays can been used to expand the number of patients receivingdrug resistance geno-typing, which can aid in determining prevalence of RT/PIemerging mutations.Methods: A previously published drug resistance genotyping assay was modified andused to genotype RT and PR genes. 19 patients virologically failing first-line regimenand 24 failing second-line regimen were studied to determine resistance patterns.Virological failure was defined as failing to maintain <1000 copies/mL during ART.Only major and minor RT and PR mutations (IAS-USA 2010) were considered foranalysis. The in-house assay was validated by comparing sequence data of 7 previouslyViroSeq tested samples and 5 randomly selected samples to determine reproducibility.Results: The in-house assay efficiently amplified all 12 validation samples with thelowest sample scoring 99.4% sequence homology. The most common RT mutation wasM184V (79% n=19) and (71% n=24) first and second-line respectively. No significantdifferences were reported in all the other RT mutations between first-line and secondlineregimens. Drug resistant PI mutations (I54V, M46I and V82A all present 20.8%)were only found in the second-line regimen and were insignificant, p= 0.0562.Conclusion: The in-house assays can be used as alternatives for commercial kits togenotype HIV-1C in Zambia without compromising test quality. The insignificant PIdrug resistant mutations which were found, despite virological failure in patients, couldindicate a possibility of other mutations within the HIV-1 genome that could reduce PIsusceptibility.

[发布机构] Stellenbosch University