HIV-1 Cervico-Vaginal Reservoir in the Era of HAART

Nunnari G¹, Kulkosky J¹, Sullivan J¹, Xu Y¹, Cavert W², Frank I³, and Pomerantz RJ¹. ¹Center for Human Virology, Thomas Jefferson University, Philadelphia, PA, USA, ²Department of Microbiology, University of Minnesota, Minneapolis, USA, ³Division of Infectious Diseases, University of Pennsylvania, Philadelphia (USA)

Background: The aim of the study was the evaluate the role played by the cervical and vaginal tract of HIV-1 infected women on stable HAART as a possible viral reservoir. Material and Methods: 12 HIV-1 infected women on virally-suppressive HAART (blood plasma HIV-1 RNA levels below 50 copies/ml) were enrolled in this study. Cervicovaginal lavage (CVL) and peripheral blood samples were obtained from 9 women, and ecto and endo cervical biopsies were obtained from 3 additional patients. Cervicovaginal cells and peripheral blood mononuclear cells (PBMC) were separated from CV fluid and blood plasma, respectively. HIV-1 RNA copies numbers were determined by gag specific RT-PCR Southern blot technique. PBMC and CV-cells, as well as ecto and endo cervical cells were co-cultured with CD8-depleted PBMCs from healthy donors and in vitro viral growth was determined by p24 ELISA. In situ hybridization, HIV-1 proviral DNA and RNA copy number were performed in both endocervical and ectocervical tissues. Results: In seven out of nine patients, cervicovaginal fluids and blood plasma were found positive for cell-free HIV-1 RNA (HIV-1 RNA copy number mean 7.6 and 15, respectively), while no viral outgrowth was detected from both PBMCs and CVL-cells co-cultures assays. Endo and ecto cervical co-cultures were also negative for HIV-1 viral growth, and neither intracellular proviral DNA nor RNA were detected (detection limit 5 copies/ml) in these tissues. Furthermore, in situ hybridization of the ecto and endo cervical tissues did not detect the presence of any clearly infected cells. Viral growth was detected from CD8-depleted PBMCs co-cultures from 3 patients. Conclusions: This study suggests that the cervicovaginal tract, unlike seminal cells, of patients on suppressive HAART, with blood plasma HIV-1 RNA copies/ml below 50, is likely not a major reservoir for HIV-1. Nonetheless, the presence of cell-free HIV-1 RNA in cervicovaginal secretions suggests the importance of practicing protected sex even in the era of HAART.