HIV-1 reverse transcriptase gene 103K/N and 184M/V combinations in tandem: detection and quantification of HIV-1 populations in the CD45RO+ T-cell compartment by a double-ARMS real-time PCR assay.

Background: The proviral HIV-1 reverse transcriptase gene for the 103K/N and 184M/V combinations were studied in tandem. The CD45RO(+) T (memory) cell compartment was investigated. Methods: A new double-ARMS (amplification refractory mutation system) real-time polymerase chain reaction assay was developed to detect and quantify 4 populations (103K-184M, 103K-184V 103N-184M, and 103N-184V) in the CD45RO(+) T-cell compartment. Twenty-one patients, 18 lamivudine and efavirenz/nevirapine experienced, were enrolled in a cross-sectional study. Results: None of the mutation combinations were detected in patients on highly active antiretroviral therapy (HAART) (naive at start) with viremia suppression below detection limits. Conversely, all patients exposed to mono- or dual therapy (prior to HAART) carried at least 1 mutation combination regardless of viral load. In 9 patients, 17 mutations were detected in a mosaic of combinations. This study provides definite evidence of the existence of 103N and 184V mutation quasi-populations in tandem, and separately in combination with the wild-type codons, 184M and 103K, in the CD45RO(+) T-cell compartment. Conclusions: The initiation and continuation of potent antiretroviral therapy effectively hinders the appearance of 103N and 184V mutations alone or in tandem in memory cells. When switching therapies because of failure, caution should be exercised with drugs associated with single-mutation threshold; they can appear in tandem with contemporary resistant virus populations, leading to multidrug resistance.