PDCD1 and type 1 diabetes mellitus: Regarding CD8+ Tregs, the percentages of PD-1+ cells was lower in the LT T1D group of patients in respect to the control subjects, in particular, the percentages relative to total PD-1 and PD-1high (Fig 4D, Kruskal–Wallis one-way analysis of variance p = 0.0397; 4e, Kruskal–Wallis one-way analysis of variance p = 0.0054; 4f, Kruskal–Wallis one-way analysis of variance p = 0.1608).