Earlier studies reported a similar tissue specific inhibitory effect of estrogen on HIV-1 replication in the cervico-vaginal tract despite similar plasma viral load.[26] Literature indicates that estrogen inhibits HIV-1 replication by suppressing HIV-1 long terminal repeats (LTR) promoter activity[27,28] thereby inhibiting HIV-1 transcription and by reducing susceptibility of CD4+ lymphocytes and macrophages to HIV-1 infection.[29,30] Further studies are needed to confirm this association. This evidence concerns the gene CD4 and HIV-1 infection.