PDCD1 and type 2 diabetes mellitus: Interestingly, when evaluating the metabolic groups, a sequential increase in PD-1+ Th1 cells from IS (54% ± 19.8) to IRn (62% ± 16.7), Pre-T2D (67% ± 14.6), and T2D (75% ± 14.9; Supplementary Table S4) was observed.