Reduced naive and increased activated CD4 and CD8 cells in healthy adult Ethiopians compared with their Dutch counterparts

Abstract

To assess possible differences in immune status, proportions and absolute numbers of subsets of CD4⁺ and CD8⁺ T cells were compared between HIV⁻ healthy Ethiopians (n = 52) and HIV⁻ Dutch (n = 60). Both proportions and absolute numbers of naive CD4⁺ and CD8⁺ T cells were found to be significantly reduced in HIV⁻ Ethiopians compared with HIV⁻Dutch subjects. Also, both proportions and absolute numbers of the effector CD8⁺ T cell population as well as the CD4⁺ CD45RA⁻ CD27⁻ and CD8⁺ CD45RA⁻ CD27⁻ T cell populations were increased in Ethiopians. Finally, both proportions and absolute numbers of CD4⁺ and CD8⁺ T cells expressing CD28 were significantly reduced in Ethiopians versus Dutch. In addition, the possible association between the described subsets and HIV status was studied by comparing the above 52 HIV⁻ individuals with 32 HIV⁺ Ethiopians with CD4 counts > 200/μl and/or no AIDS-defining conditions and 39 HIV⁺ Ethiopians with CD4 counts < 200/μl or with AIDS-defining conditions. There was a gradual increase of activated CD4⁺ and CD8⁺ T cells, a decrease of CD8⁺ T cells expressing CD28 and a decrease of effector CD8⁺ T cells when moving from HIV⁻ to AIDS. Furthermore, a decrease of naive CD8⁺ T cells and an increase of memory CD8⁺ T cells in AIDS patients were observed. These results suggest a generally and persistently activated immune system in HIV⁻Ethiopians. The potential consequences of this are discussed, in relation to HIV infection.