A deregulation of FoxP3+ Treg seems to play an important role in allergic disease since a Treg impaired function has been associated with development of allergy [28,36,37], and mutations in the foxp3 gene induce a severe autoimmunity, polyendocrinopathy and allergy (IPEX) [38]. Here, FOXP3 is linked to immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome.