CXCR4 and HIV-1 infection: In this proof of concept study we report levels of mRNA gene expression of CCL3, CCL4, CCL5 and CCR5 and CXCR4 in association with HIV-1 infection, DMPA exposure and endogenous progesterone level in a small group of women who were infected during a HIV prevention trial and a group of sexually active women who remained HIV uninfected well after the HIV prevention study ended.