The cleavage products C3a and C3b of C3 derived from the nasal epithelial cells can act to dilate the blood vessels, increase vascular permeability, promote histamine release, function as chemoattractants, activate eosinophils, regulate Th2 inflammation, and are closely related to the onset of CRSwNP (67). The gene discussed is C3; the disease is chronic rhinosinusitis with nasal polyps.