Identification of CD8+ T cell subsets that normalize in early-treated people living with HIV receiving antiretroviral therapy

Background Although combined antiretroviral therapy (cART) has decreased the mortality associated with HIV infection, complete immune reconstitution is not achieved despite viral suppression. Alterations of CD8(+) T cells and some of their subpopulations, such as interleukin (IL)-17-producing cells, are evidenced in treated individuals and are associated with systemic inflammation and adverse disease outcomes. We sought to evaluate if different CD8(+) T cell subsets are differentially normalized during a clinical follow-up of people living with HIV (PLWH) receiving suppressive cART. Methods We explored the changes in the frequencies, activation/exhaustion phenotypes (HLA-DR, CD38, PD-1, and TIM-3), and function (total and HIV-specific cells expressing CD107a, perforin, granzyme B, interferon [IFN]-gamma and IL-17) of CD8(+) T cells from early-treated PLWH receiving cART in a 1-year follow-up, using a multidimensional flow cytometry approach. Results Despite continuous cART-induced viral suppression and recovery of CD4(+) T cells, after a 1-year follow-up, the CD8(+) T cell counts, CD4:CD8 ratio, PD-1 expression, and IL-17 production by CD8(+) T cells exhibited incomplete normalization compared with seronegative controls. However, the proportion of CD8(+) T cells with an exhausted phenotype (co-expressing PD-1 andTIM-3), and cells co-expressing cytotoxic molecules (Perforin and Granzyme B), reached normalization. Conclusions Although suppressive cART achieves normalization of CD4(+) T cell counts, only particular subsets of CD8(+) T cells are more rapidly normalized in PLWH receiving cART, which could be routinely used as biomarkers for therapy efficiency in these patients.