Immune responses and autoimmunity are tightly controlled via expression of immunosuppressive/immunoregulatory molecules such as CTLA-4, PD-1/PD-L1, and BTLA that, in turn, are regulated via activation of transcription factors NFAT, NF-κB, STAT3 or STAT4 [165, 166, 167]. Here, STAT3 is linked to Autoimmunity.