Plasma galectin-9 relates to cognitive performance and inflammation among adolescents with vertically acquired HIV

Objective: Adolescents with perinatally acquired HIV (AWH) are at an increased risk of poor cognitive development yet the underlying mechanisms remain unclear. Circulating galectin-9 (Gal-9) has been associated with increased inflammation and multimorbidity in adults with HIV despite antiretroviral therapy (ART); however, the relationship between Gal-9 in AWH and cognition remain unexplored. Design: A cross-sectional study of two independent age-matched cohorts from India [AWH on ART (n = 15), ART-naive (n = 15), and adolescents without HIV (AWOH; n = 10)] and Myanmar [AWH on ART (n = 54) and AWOH (n = 22)] were studied. Adolescents from Myanmar underwent standardized cognitive tests. Methods: Plasma Gal-9 and soluble mediators were measured by immunoassays and cellular immune markers by flow cytometry. We used Mann – Whitney U tests to determine group-wise differences, Spearman’s correlation for associations and machine learning to identify a classifier of cognitive status (impaired vs. unimpaired) built from clinical (age, sex, HIV status) and immunological markers. Results: Gal-9 levels were elevated in ART-treated AWH compared with AWOH in both cohorts (all P < 0.05). Higher Gal-9 in AWH correlated with increased levels of inflammatory mediators (sCD14, TNFa, MCP-1, IP-10, IL-10) and activated CD8⁺ T cells (all P < 0.05). Irrespective of HIV status, higher Gal-9 levels correlated with lower cognitive test scores in multiple domains [verbal learning, visuospatial learning, memory, motor skills (all P < 0.05)]. ML classification identified Gal-9, CTLA-4, HVEM, and TIM-3 as significant predictors of cognitive deficits in adolescents [mean area under the curve (AUC) = 0.837]. Conclusion: Our results highlight a potential role of Gal-9 as a biomarker of inflammation and cognitive health among adolescents with perinatally acquired HIV.