Significance of interleukin-17A in patients with nasal polyposis

Interleukin-17A (IL-17A) is a key inflammatory cytokine in many disorders, while the significance of IL-17A in nasal polyposis (NP) is still obscure. This study aimed to investigate the expression of IL-17A in nasal polyps from both atopic and nonatopic patients and its associations with clinical and histological features.

In all, 30 patients with NP were included, and were grouped into atopic and nonatopic patients according to skin prick test (SPT). Disease severity was evaluated by symptom score, endoscopy score and CT score. Histological characteristics were assessed by eosinophilic infiltration, basement membrane (BM) thickness, epithelial damage, squamous metaplasia, and goblet cell hyperplasia. IL-17A expression in polyps was detected by ELISA and immunohistochemistry.

Endoscopy score and CT score were significantly higher in atopic NP patients than in nonatopic NP patients (p < 0.05). IL-17A levels were significantly upregulated in both atopic (p < 0.01) and nonatopic (p < 0.05) patients versus controls. Furthermore, IL-17A levels were significantly higher in the atopic group versus nonatopic group. Significantly positive correlations were found between IL-17A levels and CT scores, eosinophilic infiltration and BM thicknesses.

These results indicated that expression of IL-17A was significantly upregulated in NP patients and was more severe in atopic NP patients, suggesting that IL-17A may play an important role in the pathology of NP and atopy may contribute to NP by stimulating the production of IL-17A.