In an effort to use immunological abnormalities as markers of HI V -I infectionrnprogression in Ethiopian individuals, this work assessed the changes in in vitro and inrnvivo T-cell responses to recall M. tuberculosis antigen, purified protein derivativern(PPO). This was further evaluated against C04+ and C08+ T-cells count and viral loadrnin the same subjects. Peripheral blood mononuclear cells (PBMCs) isolated from 36rnHIV -I seropositive and 105 seronegative individuals were subjected to 6 days in vitrornPPO stimulation and cytokine production. The T-cell proliferative response was thenrnevaluated using 5-bromo-2-deoxyuridine (BrdU) instead of thymidine incorporation asrna method of assay. Cytokines (IFN-y and IL-4) production was measured in the PBMCrnculture supernatants using sandwich ELISA. Three days phytoheamagglutinin (PHA)rnstimulation responses were used as positive controls. In vivo tuberculin PPO responsesrnwere measured for 18 HIV -I seropositive and 74 seronegative individuals by standardrnMantoux reaction. Results show that T-cell responses to PPO both in vitro and in vivornwere affected by HIV -I infection, in contrast to HIV -I seronegatives. Significantrnreduction in IFN-y production was also observed between the two groups followingrnPPO stimulation (p = 0.000), but not with IL-4. Thus, a shift from Thl to Th2rncytokines production was not observed. Analysis of T --;;ell responses to PPO showed arnpositive correlation with C04+ T cell counts, and negative with plasma viral load. Thisrnconfirmed that HIV -I infection progression is followed by a depletion of C04+ T cellsrncount and high viral load. Change in proliferation and cytokine production was specificrnto PPO. It suggests that Alycobacteriulll tuberculosis specific immune responses arernaffected in HIV -I infected sUbjects. Taken together our results indicated that evaluatingrnT-cell responses to recall antigen, PPO can be used as an early marker for HIV -Irninfection progression.of unemployment, sexual promiscuity and the presence of a wide diversity of HIV-Irnsubtypes in Africa have also been indicated as powerful components in HIV -I spread andrntransmission.rnThe virus has profound economic and social implications for both developed andrndeveloping countries. No country in the world is free of the disease and can claim that itrnhas stopped its spread. The most effective and efficient method to prevent HIV -infectionrnand disease manifestation would be through vaccination and effective treatment, whichrncurrently are not available. The generally accepted method of implementing preventivernstrategies for HIV infection is education that will inform and increase awareness of thernsociety