IL13 and nasal cavity polyp: IL‐13, IL‐4Rα, IL‐13Rα1, and MUC5AC were found to be highly expressed in nasal polyp tissue from patients with eosinophilic chronic rhinosinusitis (ECRS), and IL‐13 expression was positively correlated with MUC5AC expression, indicating that IL‐13 can directly regulate mucin hypersecretion.61