FOXP3 and polyendocrinopathy: The Foxp3 transcription factor, through its expression in Treg cells, is essential for the prevention of autoimmunity as shown in the human immune dysregulation, polyendocrinopathy, enteropathy, X‐linked (IPEX) syndrome, as well as in scurfy and Foxp3−/− mice.24, 25, 26 The generation of tTreg cells also depends on the presentation of self‐antigens by thymic MHC proteins.