TSLP and viral infectious disease: The protease activity of antigens such as Streptococcus and HDM, as well as, fungal and viral infections, can cause the airway epithelium to secrete three epithelial-derived allergens, including IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) (47), which promote or modulate Th2 immunity by directly or indirectly affecting DC function, ultimately mediating the inflammatory immune response in asthmatic airways.