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

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.