Glucocorticoids have been suggested to amplify the IL-2-dependent expansion of FOXP3+CD4+CD25+ T cells in vivo (129), increase FOXP3 expression by Tregs in patients affected by asthma (130), and restore the impaired suppressive function of Tregs in patients with relapsing multiple sclerosis (131). Here, FOXP3 is linked to asthma.