CD38 expression on CD8+ T cells as a marker of immune activation and ART efficacy in HIV

Antiretroviral therapy (ART) is treatment for people infected with human immunodeficiency virus (HIV). We aimed to investigate the short-term effects of ART on T lymphocyte counts and the expression of activation markers, CD38 and HLA-DR, on CD4+ and CD8+ T cells. Thirty HIV patients (people with HIV (PWH) group), 30 patients who received 3 months of ART (PWH on ART group), and 20 HIV-negative controls were included in the study. Whole blood samples were collected in ethylenediaminetetraacetic acid-containing tubes. The percentages of CD38- and HLA-DR-expressing T cells were estimated by flow cytometric assay. Absolute counts were calculated by the double platform method. Viral load was analyzed by the PCR method. PWH showed a significant decrease in CD4+ T cells, with numerical recovery after 3 months of ART (<i>p</i> = 0.001), while CD8+ T cells increased (<i>p</i> = 0.011) and remained unchanged post-ART (<i>p</i> = 0.943), despite a percentage decrease (<i>p</i> = 0.031). After adjusting for CD4+ T cell counts, there was no significant difference in the percentage of CD4+CD38+ T cells among the groups. In contrast, CD8+CD38+ and CD8+HLA-DR+ T cells significantly increased in the PWH group (<i>p</i> < 0.001) and decreased after ART (<i>p</i> < 0.001, <i>p</i> = 0.003), even after adjusting for CD8+ T cell counts and other potential confounders. The percentage of CD4+CD38+ T cells was negatively (<i>r</i> = -0.578, <i>p</i> = 0.030), and CD8+CD38+ T cells were positively correlated with viral load (<i>r</i> = 0.530, <i>p</i> = 0.013). However, we observed no correlation between HLA-DR-expressing CD4+ and CD8+ T cells and viral load. These findings suggest that CD8+CD38+ T cells could serve as a useful marker for both immune activation and assessing the effectiveness of ART in HIV patients.