FOXP3 and polyendocrinopathy: However, ours is only a proof-of concept study that can be easily adapted to the lentiviral delivery system, as has successfully been shown in PBMC from immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome patients, which was able to generate a large pool of FoxP3 expressing Tregs, phenotypically and functionally identical to Tregs from healthy donors (72).