IL-33 Expression in Chronic Rhinosinusitis with Nasal Polyps and Its Relationship with Clinical Severity

Chronic rhinosinusitis (CRS) is a heterogeneous disease characterized by epithelial inflammation and tissue eosinophilic infiltration. Interleukin-33 (IL-33) is a key inflammatory cytokine that mediates eosinophilic infiltration.

The aim of our study was to investigate the expression and role of IL-33 in eosinophilic CRS with nasal polyps (ECRSwNP) and in noneosinophilic CRS with nasal polyps (nECRSwNP), and to analyze their correlation with clinical severity.

The study enrolled 25 patients with ECRSwNP, 27 patients with nECRSwNP, and 12 control subjects, based on immunohistochemical staining. Protein and mRNA expressions of IL-33 in sinus mucosal samples were determined by immunohistochemistry and real-time polymerase chain reaction. Sino-Nasal Outcome Test-20 (SNOT-20) score, visual analog scale (VAS) score, endoscopy score, and computed tomography (CT) score were assessed preoperatively.

IL-33 expression levels in the CRSwNP group were significantly higher than those in the control group (p < 0.01), especially in the ECRSwNP group (p < 0.05). There were no significant differences between the ECRSwNP and nECRSwNP groups with respect to SNOT-20 score, VAS score, endoscopy score, or CT score. IL-33 mRNA expression showed a positive correlation with the number of eosinophils (p < 0.05) and endoscopy score (p < 0.05) but not with VAS score and CT score.

IL-33 expression plays an important role in patients with CRSwNP. No significant differences were observed between the ECRSwNP and nECRSwNP groups with respect to SNOT-20 score, VAS score, endoscopy score, or CT score. IL-33 expression was correlated with eosinophil counts and endoscopy score.