Differences in CSF and plasma levels of Gal-9 among younger (<40) and older (40-70) HIV negative (HIV−), HIV+ ART suppressed, and CSF HIV VL detectable (a). Correlations between CSF and plasma Gal-9 levels and age among participants HIV-, HIV+ ART suppressed, or HIV+ CSF VL detectable (b). Differences between groups were analyzed by Mann-Whitney tests. Associations between variables were analyzed by Spearman correlations. Statistical significance is indicated as *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001.