CXCR5 and type 1 diabetes mellitus: As previously described [4, 15, 22], based on CXCR5 and PD‐1 expression we divided peripheral blood memory CD4+ T cells into CXCR5−PD‐1hi (putative cTph cells) and CXCR5+PD‐1hi (putative cTfh cells), as well as into CXCR5−PD‐1lo and CXCR5+PD‐1lo fractions (Figure 1A), and analyzed these in a cohort including 27 children with newly diagnosed T1D, 29 AAb+ subjects who later progressed to T1D, as well as 57 age‐matched healthy controls.