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.