The Effect of Progesterone Levels and Pregnancy on HIV-1 Coreceptor Expression

The upregulation of HIV-1 co-receptor expression during certain clinical settings may explain the predisposition of individuals to enhanced HIV-1 acquisition. We sought to determine the effect of estrogen and pregesterone on the HIV-1 coreceptors, CCR5 and CXCR4. Co-receptor expression on CD3- and CD14-positive cells obtained systematically and locally (genital tissue in women) was determined in men, pre- and post-menopausal women, pregnant women in each trimester and in labor. CCR5 on both CD3- and CD14-positive cells was highest in pregnant women, and increased as gestation advanced (P < .01 and P < .001, respectively). Progesterone levels were significantly associated with CCR5 expression on PBMCs (P < .03 for CD3-positive, and P < .002 for CD14-positive cells) and from cells isolated from tissue (P < .001). CCR5 mRNA expression correlated with the cell surface marker expression from blood and tissue. These findings suggest that pregnancy and other high progesterone states may predispose women to HIV-1 acquisition.