CXCR4 and HIV infectious disease: Since the detected increase in viral replication in HIV-1-infected cells in the presence of hormones was not induced by the enhanced production of CCR5 or CXCR4 co-receptors, we decided to investigate the possible effect of hormones on the expression of Toll-like receptors (TLRs), which, according to recent studies, might also play a key role in HIV infection [86,87,88,89].