Examining functional alterations of HIV-1 Tat variants associated with neurocognitively impaired patients in the Drexel Medicine CARES Cohort
Journal of virus eradication
of residual viremia. Current viral quantification methods are limited by lack of sensitivity or the need for specialized, lengthy processing. Methods: The Aptima HIV-1 Quant Assay provides standard viral load (VL) measurements on a 0.5 mL sample, but it also provides a reactive/non-reactive digital readout that may be reasonably sensitive even when only a single copy is present in the 0.5 mL sample. Readouts on multiple replicates (reps) on the system's automated platform using the standard
... ng the standard sample volume can provide ultrasensitive estimates of copies/mL (cp/mL) via Poisson analysis. An analytical panel comprised of 5 serial dilutions each of 4 HIV+ samples was blindly tested using the Aptima Assay in 45 reps on 25 mL per dilution, and 110 large volume samples from antiretroviral-suppressed RAVEN study participants with consistently negative standard VL assay results were subjected to rep testing. Results: Dilutions of the 4 samples calculated to range from 9 to 0.2 cp/mL had VL estimates generated via the 45-rep Poisson analysis that ranged from no underestimation to underestimation of the target concentrations up to 3-fold. On initial 9-rep testing of 110 samples from 59 ART-treated adults followed in the RAVEN cohort, 63 samples from 37 individuals had detectable VL. An additional 36 reps were performed on a subset of 19 samples, 7 of which were initially undetectable. Four of seven initially undetectable samples had positive results when tested with the additional reps. The Poisson-derived estimates in the 19 samples tested with 45 total reps ranged from 0 [95% CI 0 -0.18] to 2.197 [95% CI 1.52 -3.21] cp/mL. Conclusions: The Aptima HIV-1 Quant Assay provides a high throughput means to quantify VL to <1 cp/mL with large volume plasma specimens which allows detection and quantitation of VL in most ART-suppressed patients. Given the assay's performance characteristics, its lack of reliance on specialized specimen handling and the highly automated approach, this assay is well-suited to earlyand late-phase clinical trials of HIV curative interventions.