In particular, it has been shown that on allergen exposure, several epithelial cytokines, such as IL-25, IL-33, and thymic stromal lymphopoietin (TSLP), are involved in the pathogenesis of asthma.5, 6 Moreover, several genes discovered in genome-wide association studies (ie, IL-33, IL-1RL1, and TSLP) support a key role for these cytokines.7, 8 On the one hand, these epithelium-derived cytokines have the capability to activate the adaptive immune system by stimulating TH2-polarizing dendritic cells (DC).5 This evidence concerns the gene TSLP and asthma.