IL13 and chronic rhinosinusitis with nasal polyps: In addition, it also promotes the adhesion of eosinophils via α4β1 integrin expressed on human eosinophils [45], prolonging eosinophil survival [45], and stimulates mediator release, including IL-13 and GM-CSF [6]; all activities may contribute to the localization and activation of eosinophils in polyp formation in CRSwNP patients.