Growing evidence suggests that CRSwNP in Western patients is characterized by a TH2-based immune response with high interleukin (IL)-5 levels and abundant eosinophilic infiltration, whereas studies of CRSwNP in Asian patients predominantly show a mixed T cell immune response and non-eosinophilic inflammation [3–9]. Here, IL5 is linked to chronic rhinosinusitis with nasal polyps.