Lack of HIV tat-gene amplification in blood monocytes compared to T lymphocytes

T-lymphocytes (T-Ly) and monocytes/macrophages are thought to be the main in vivo targets for HIV 1. We previously demonstrated, using the polymerase chain reaction (PCR), that HIV provirus could be detected in 20 out of 21 T-Ly samples and 13 out of 21 monocyte samples from HIV 1-seropositive individuals, with at least gag, env or LTR primers. In the present study, we wanted to find out whether the HIV 1 tat gene could be detected in 14 of these circulating monocyte and T-Ly samples. The tat primers were chosen in order to amplify the overall second exon of this regulatory gene. This new set of primers could not detect HIV provirus in monocytes but it did in T-Ly, among cells previously shown to be positive with one of the other 3 primer pairs. Further molecular studies should help characterize these probable monocytotropic variants and elucidate their contribution to HIV pathogenesis.