PTPN2 and autoimmune disease: This is reminiscent of the results of several genome wide associations studies (GWAS) that recently described a number of susceptibility genes associated with a variety of autoimmune diseases, such IL-2, the IL-2 receptor alpha chain (CD25), CTLA-4, and PTPN2, a phosphatase involved in downstream signaling of the IL-2 receptor [62–66].