Association of plasma viremia with HIV-1 RNA levels in cervicovaginal lavage secretions in HIV-1 seropositive ART naïve women from Pune, India

Systemic Immune Activation and HIV Shedding in the Female Genital Tract

BACKGROUND

Plasma HIV RNA is the most significant determinant of cervical HIV shedding. However, shedding is also associated with sexually transmitted infections (STIs) and cervical inflammation. The mechanism by which this occurs is poorly understood. There is evidence that systemic immune activation promotes viral entry, replication, and HIV disease progression. We hypothesized that systemic immune activation would be associated with an increase in HIV genital shedding.

METHODS

Clinical assessments, HIV RNA in plasma and genital secretions, and markers of immune activation (CD38(+)DR(+) and CD38(-)DR(-)) on CD4(+) and CD8(+) T cells in blood were evaluated in 226 HIV+ women enrolled in the Women's Interagency HIV Study. There were 569 genital evaluations of which 159 (28%) exhibited HIV RNA shedding, defined as HIV viral load >80 copies per milliliter. We tested associations between immune activation and shedding using generalized estimating equations with logit link function.

RESULTS

In the univariate model, higher levels of CD4(+) and CD8(+) T-cell activation in blood were significantly associated with genital tract shedding. However, in the multivariate model adjusting for plasma HIV RNA, STIs, and genital tract infections, only higher levels of resting CD8(+) T cells (CD38(-)DR(-)) were significantly inversely associated with HIV shedding in the genital tract (odds ratios = 0.44, 95% confidence interval: 0.21 to 0.9, P = 0.02).

CONCLUSIONS

The association of systemic immune activation with genital HIV shedding is multifactorial. Systemic T-cell activation is associated with genital tract shedding in univariate analysis but not when adjusting for plasma HIV RNA, STIs, and genital tract infections. In addition, women with high percentage of resting T cells are less likely to have HIV shedding compared with those with lower percentages. These findings suggest that a higher percentage of resting cells, as a result of maximal viral suppression with treatment, may decrease local genital activation, HIV shedding, and transmission.

Evaluation of Performance Characteristics of the Aptima HIV-1 Quant Dx Assay for Detection and Quantitation of Human Immunodeficiency Virus Type 1 in Plasma and Cervicovaginal Lavage Samples

Quantification of HIV-1 RNA has become the standard of care in the clinical management of HIV-1-infected individuals. The objective of this study was to evaluate performance characteristics and relative workflow of the Aptima HIV-1 Quant Dx assay in comparison with the Abbott RealTime HIV-1 assay using plasma and cervicovaginal lavage (CVL) specimens. Assay performance was evaluated by using an AcroMetrix HIV-1 panel, AcroMetrix positive controls, Qnostics and SeraCare HIV-1 evaluation panels, 208 clinical plasma samples, and 205 matched CVL specimens on the Panther and m2000 platforms. The Aptima assay demonstrated good linearity over the quantification range tested (2 to 5 log10copies/ml), and there was strong linear correlation between the assays (R(2)= 0.99), with a comparable coefficient of variance of <5.5%. For the plasma samples, Deming regression analyses and Bland-Altman plots showed excellent agreement between the assays, with an interassay concordance of 91.35% (kappa = 0.75; 95% confidence interval [CI], 0.65 to 0.85), and on average, the viral loads determined by the Aptima assay were 0.21 log10copies/ml higher than those determined by the RealTime assay. The assays differed in their sensitivity for quantifying HIV-1 RNA loads in CVL samples, with the Aptima and RealTime assays detecting 30% and 20%, respectively. Aptima had fewer invalid results, and on average, the viral loads in CVL samples quantified by the Aptima assay were 0.072 log10copies/ml higher than those of the RealTime assay. Our results demonstrate that the Aptima assay is sensitive and accurate in quantifying viral loads in both plasma and CVL specimens and that the fully automated Panther system has all the necessary features suitable for clinical laboratories demanding high-throughput sample processing.