Activation and maturation of peripheral blood T cells in HIV‐1‐infected and HIV‐1‐uninfected adults in Burkina Faso: a cross‐sectional study

Abstract

BackgroundWe wanted to explore to what extent environmental exposure to immune stimulants, which is expected to be more present in rural than in urban settings, influences T cell activation and maturation in healthy and in HIV-1-infected individuals in Burkina Faso in west Africa.MethodsThe proportion of circulating naïve T cells and the expression of the T cell activation markers, CD95 and CD38, were analyzed by immunophenotyping and three-colour flow cytometry in 63 healthy individuals and 137 treatment-naïve HIV-1-infected subjects from Ouagadougou (urban setting) and 26 healthy adults and 61 treatment-naïve patients from Nouna (rural).ResultsA slightly higher activation level of CD4+ and CD8+ peripheral blood T cells was seen in healthy adults living in Nouna than in those living in Ouagadougou. The percentages of naïve CD45RAbright CCR7+ T cells were not significantly different between both study sites. Taking into consideration that relatively more HIV-1-infected patients in Nouna were in an advanced disease stage, no relevant differences were seen in T cell activation and maturation between patients at both study sites. As expected, the percentage of CD95+ CD4+ and CD38+ CD8+ T cells and the respective antigen density on these cells was significantly higher in patients than in controls in both settings. The percentage of naïve CD8+ T cells was lower in HIV-1-infected subjects than in healthy controls irrespective of the study site, while a lower proportion of naïve CD4+ T cells in patients compared with controls was seen only in Nouna.ConclusionsEnvironmentally triggered immune activation may contribute to the increased expression of the activation markers CD95 and CD38 on peripheral blood T cells from healthy adults living in rural versus urban settings in Burkina Faso. T cell activation is further increased in HIV-1-infected individuals due to T cell loss and high plasma viral load levels. The observed variations in T cell activation levels or the proportion of naïve T cells in our study patients, however, are not explained by differences in CD4+ T cell counts or HIV-1 plasma viral load levels alone.

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“… Tiba et al (2011) in Burkina Faso, Africa, noted different expression of CD38 on CD8 + T cells among healthy individuals. The authors hypothesised that environmental exposure may influence peripheral blood T cell activation.…”

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“…3A,C ) that are consistent with previous studies. Alterations in the frequencies of CD8+ naive and T EM during the course of HIV infection have been described 26 with an expanded T EM cell population 27 , 28 and lower frequency of naive T cells 29 compared to healthy controls or acutely infected persons. This skewed distribution of memory phenotypes has been associated with immune activation and disease progression.…”