PTPN22 and atopic eczema: The targets included thymic stromal lymphopoietin (TSLP) in asthma; T helper (Th)2 and Th22 cells and their respective cytokines (interleukin [IL]-4R and IL-22) in atopic dermatitis; inhibitory/regulatory molecules involved in T-cell modulation, and protein tyrosine phosphatase, non-receptor type 22 (PTPN22) in rheumatoid arthritis; low-dose IL-2 therapy in SLE; and pro-resolution mediators in ulcerative colitis and asthma.