Role of incidental and/or cured intestinal parasitic infections on profile of CD4⁺ and CD8⁺ T cell subsets and activation status in HIV-1 infected and uninfected adult Ethiopians

Intestinal parasitic infections have been suggested to cause persistent immune activation leading to an unbalanced immune state. Such a state has been proposed to be a major factor in the pathogenesis of AIDS in an African context. The present study investigated the effect of incidental parasitic infection and treatment on the profile of T cell differentiation and activation markers on CD4+ and CD8+ T cells from HIV-1 infected and uninfected adult Ethiopians. Cryopreserved PBMCs from 64 subjects (41 HIV-negative and 23 HIV-positive) with follow-up visits at 6-monthly intervals were used to compare the effect of incidental intestinal parasites and their treatment upon T cell subset profiles and activation status. The samples were stained with antibodies to various T cell differentiation and activation markers allowing naive, memory, effector, memory/effector, activated and resting CD4+ and CD8+ T cell subsets to be quantified by triple-colour FACScan. Incidental intestinal parasitic infections resulted in a significant increase in memory CD4+ T cell numbers both in HIV-negative and HIV-positive subjects (P < 0.05). There was also a significant increase in the percentage of CD8+ HLA-DR+ T cells (P < 0.05) in HIV-positive subjects co-infected with parasites. In HIV-negative subjects, a significant decline in activated cells and a significant increase in resting CD8+ T cells (P < 0.05) was observed after treatment for parasites. These data suggest that intestinal parasitic infections could result in the alteration of T cell subset counts and also in the up-regulation of T cell activation markers in peripheral blood. Treatment of parasitic infections showed a tendency to reduce the activation suggesting that, together with other community based intervention strategies, such treatment could be used to down-regulate immune activation and hence protect the host from being easily attacked by HIV.