In most patients, CRSwNP is related to type 2 airway inflammation, an inflammatory pattern characterized by a peculiar subset of CD4+ T cells known as Th2 cells that secrete type 2 cytokines such as interleukin-4 (IL-4), interleukin-5 (IL-5), and interleukin-13 (IL-13), by high levels of IgE and increased eosinophils [16]. This evidence concerns the gene IL4 and chronic rhinosinusitis with nasal polyps.