A statistically significant reduction in the percentage of memory B cells (CD19+CD27+) was observed in individuals heterozygous for the C/T PTPN22 variant (both healthy individuals and T1D patients) compared to C/C individuals (KS-test p>0.10; unpaired t test with Welch’s correction p = 0.0359).(Figure S1B). Here, CD27 is linked to type 1 diabetes mellitus.