IL4 and chronic rhinosinusitis with nasal polyps: In many cases, CRSwNP is characterized by the activation of type 2 inflammatory pathways, with a series of concatenated effects that lead to an increase in the concentration of eosinophils (systemic and/or local), IgE (systemic or even just local), and interleukins IL-4, IL-5, and IL-13 [3,4].