TSLP and inflammatory response: Airway epithelial cells are the first line of defense against environmental allergens (8) and secrete IL-33, IL-25, and thymic stromal lymphopoietin (TSLP) that can induce Th2 cells and type 2 innate lymphoid cell (ILC2) activation to potentiate allergen-induced Th2-associated airway inflammation (9, 10).