ABSTRACT: We used Affymetrix U133A 2.0 chips to better understand transcriptional changes associated with HIV-1 infection and perinatal transmission in human PBMCS obtained from young adult mothers with infants in Botswana in vivo. HIV seropositive and drug naïve samples: GSM94333, GSM94334, GSM94335, GSM94336, GSM94337, GSM94338, GSM94340, GSM94342, GSM94343, GSM94345, GSM94351, GSM94353, GSM94354, GSM94355, GSM94357, GSM94358, GSM94360, GSM94361, GSM94362, GSM94364, GSM94365, GSM94367, GSM94369, GSM94370, GSM94378 HIV seronegative samples: GSM92590, GSM92788, GSM92789, GSM92790, GSM92791, GSM92792, GSM92793, GSM92794, GSM92795, GSM92796, GSM92797, GSM92798, GSM92799, GSM92800, GSM92801, GSM92802, GSM92803, GSM92804, GSM92805, GSM92806 HIV seropositive transmitter mothers: GSM94333, GSM94334, GSM94335, GSM94336, GSM94337, GSM94338, GSM94340, GSM94342, GSM94343, GSM94345, GSM94378 HIV seropositive nontransmitter mothers: GSM94351, GSM94353, GSM94354, GSM94355, GSM94357, GSM94358, GSM94360, GSM94361, GSM94362, GSM94364, GSM94365, GSM94367, GSM94369, GSM94370 Keywords: Cross-sectional, peripheral host response to HIV-1 infection, transmission associated gene expression.