Thymic stromal lymphopoietin (TSLP)—which is a member of the four-helix-bundle cytokine family and paralog of the cytokine IL-7—plays a fundamental role in maintaining immune homeostasis and has been linked to the pathogenesis of type 2 inflammatory diseases, including atopic dermatitis (AD), food-hypersensitivity reactions, and asthma [1]. This evidence concerns the gene TSLP and asthma.