PTPN22 and type 1 diabetes mellitus: Neutrophils isolated from the healthy donors WT (n = 5, mean age 31.10 years), PTPN22 C1858C T1D patients (n = 6, mean age 11.58 years), and PTPN22 C1858T T1D patients (n = 10, mean age 13.57 years) exhibited a significantly greater ability to produce ROS in response to TNF-α priming, fMLP stimulation, or the combination of TNFα+fMLP (Figures 2A–C).