Mass cytometry profile of PBMCs from 12 recent-onset T1D patients 15 months post-GAD65 Alum administration into an inguinal lymph node showed, among other changes, a significant increase in Tfh cells, which are heavily engaged in IL-17 and IL-21 secretion, upregulation of PD-1+CD8+ T-cells, and reduction in naïve memory B-cells (Barcenilla et al, 2021). Here, PDCD1 is linked to type 1 diabetes mellitus.