Vaginal Flora May Affect HIV RNA Concentrations


CHARLESTON, S.C. — Certain vaginal isolates affect the quantity of HIV RNA in cervicovaginal lavage, a study suggests.

Hydrogen peroxide-producing lactobacilli, for example, were associated with a significant decrease in cervicovaginal lavage (CVL) HIV RNA concentrations, and Trichomonas vaginalis, Prevotella bivia, and Mycoplasma hominis. Other anaerobes were associated with increases in CVL HIV RNA concentrations, Jane Hitti, M.D., reported at the annual meeting of the Infectious Diseases Society for Obstetrics and Gynecology.

Factors affecting the HIV RNA concentrations are important, because genital viral load is an important determinant of sexual and perinatal HIV transmission, she noted.

For the study, 38 HIV-positive women completed 163 study visits. Vaginal cultures, CVL, and plasma were collected at each visit for HIV RNA quantitation. Of 163 CVL samples, 95 had detectable HIV RNA, and the levels correlated significantly with plasma HIV RNA levels, said Dr. Hitti of the University of Washington, Seattle.

After adjustment for log plasma HIV RNA, the log difference in CVL HIV RNA was significant for H2O2 lactobacillus and T. vaginalis. Increased CVL HIV RNA concentrations were associated, although not significantly, with M. hominis, P. bivia, black gram negative rods, Candida albicans, and bacterial vaginosis or indeterminate flora.

Also, CVL HIV RNA concentrations were increased with higher vaginal concentrations of IL-8 in this study.

Several vaginal isolates appear to directly influence CVL viral load, and the effects appear to be independent of plasma viral load, she concluded, noting that an antibiotic treatment trial is underway to determine whether treatment for bacterial vaginosis and associated infections will decrease genital viral load.

“A very logical next step would be looking at ways to augment endogenous lactobacilli and looking at what effects that has,” she said.

The prevalence of H202-producing lactobacilli is lower than what has been reported among HIV-negative women, even in the presence of bacterial vaginosis, she explained.

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