Innate and adaptive abnormalities in youth with vertically acquired HIV through a multicentre cohort in Spain

Immune abnormalities have been described among youth with vertically acquired HIV (YWVH) despite antiretroviral treatment (ART). The CD4/CD8 ratio could be a useful prognostic marker. We assess immune activation and senescence in a cohort of YWVH in comparison to youth without vertically acquired HIV.

YWVH under suppressive ART were included and compared to a group of HIV-negative donors (HD) matched by age and sex, from September 2019 to September 2020. Subset distribution and expression of activation, maturation, senescence and exhaustion markers on T and NK cells were studied on peripheral blood mononuclear cells by multiparametric flow cytometry.

Thirty-two YWVH (median age: 24.4 years (interquartile range: 22.5 to 28.3 years)) were included. Among YWVH, CD4- and CD8-T cells showed high levels of activation (HLA-DR/CD38), IL-7 receptor expression (CD127) and exhaustion (TIM-3). Regarding NK cells, YWVH showed increased levels of activation and exhaustion markers compared to HD. Strong inverted correlations were observed between T-cell activation (HLA-DR/CD38), senescence (CD57) and exhaustion (TIGIT, PD-1) levels with the CD4/CD8 ratio among YWVH. HLA-DR, CD69, NKG2D and NKG2A expression levels on NK cells also correlated with the CD4/CD8 ratio. Age at ART initiation was directly associated with higher frequency of CD16^high NK-cell subsets, exhaustion T-cell levels (CD57, TIM3) and NK cells activation levels.

Immunological changes associated with vertically acquired HIV, characterized by increased activation and exhaustion levels in innate and adaptive immune components, are only partially restored by ART. The CD4/CD8 ratio can be a useful marker of disease progression for routine clinical practice.