CpG stimulation of PBMC for 4 days resulted in greater expansion of IgM+ memory B cells (CD19+CD27+IgM+) and IgM- Plasma cells (CD19+CD27hiIgM-) in PTPN22620R/W patients with T1D compared to PTPN22620R/R patients with T1D and in healthy control PTPN22620R/W donors compared to healthy control PTPN22620R/R donors (99). This evidence concerns the gene CD19 and type 1 diabetes mellitus.