Inversion of CD4⁺/CD4^- ratio in human iNKT cell ontogenesis. Histogram shows frequency of CD4, CD161, and CD56 expression in iNKT cells from CD8-depleted thymocytes compared to their counterparts from CB and adult PBMCs. Data are mean ± SD from thymuses, CB, and PBMCs obtained from 10, 8, and 12 individuals, respectively. Expression levels in CB and PB compared to that in thymus using one-way ANOVA; ^** and ^*** indicate that the P value is less than .01 and .001, respectively.