Effects of progesterone on the content of CCR5 and CXCR4 coreceptors in PBMCs of seropositive and exposed but uninfected Mexican women to HIV-1

► P regulates HIV coreceptors in PBMCs from HIV seronegative and seropositive women. ► CCR5 expression is down-regulated while that of CXCR4 is up-regulated by P. ► In exposed but uninfected women to HIV, CCR5 and CXCR4 are down-regulated by P. ► P receptor isoforms (PR-A and PR-B) are expressed in PBMCs from women. ► RU486 does not block P effects on CCR5 and CXCR4 expression. CCR5 and CXCR4 play an important role in the establishment of HIV infection and disease progression. Caucasian people exposed to HIV but uninfected (EU) present a deletion of 32bp in CCR5 that has not been reported in EU Hispanics from Latin America. Therefore, other factors besides mutations should be involved in this phenomenon. Studies in healthy women have shown that sex hormones such as progesterone (P) can modulate CCR5/CXCR4 expression through an unknown mechanism. The aim of this paper was to determine the role of P in the regulation of CCR5 and CXCR4 in peripheral blood mononuclear cells (PBMCs) of HIV-1 infected and EU women. We analyzed HIV-1-infected women with stable highly active antiretroviral therapy (HAART) with CD4+ cell counts