,23 PTPN2 directly dephosphorylates several transducers of cytokine receptor signaling including the STAT family of transcription factors (STATs 1/3/5/6) and JAK1 and JAK3 that are activated by inflammatory cytokines such as IFNγ.22, 23, 24 JAK inhibitors have emerged as an effective new therapeutic class in many patients with autoimmune diseases. This evidence concerns the gene PTPN2 and autoimmune disease.