Objective: To study the concentration and expression of IL-5 in nasal polyp tissues and explore its significance in the micro-environment differentiation of eosinophils accumulation and clarify the conception of nasal polyposis.
Methods: The concentration and expression of IL-5 in nasal polyp tissues of 40 patients were determined by ELISA and immunohistochemistry, and inferior turbinate mucosa from patients with nasal polyps and healthy volunteers was used as control.
Results: 1. IL-5 concentration in the polyp tissues was significantly higher than that in inferion turbinate mucosa(P < 0.05). There was no significant difference in inferion turbinate mucosa between the patients with nasal polyps and healthy volunteers (P > 0.05). IL-5 concentration in polyp tissues was markedly higher in patients with extensive polypoid change of nasal mucosa, history of previous polypectomy and allergic rhinitis compared with those without these features (P < 0.05). IL-5 concentration had no correlation with age and sex (P > 0.05). 2. 80.1% of the eosinophils were positive for IL-5 and 90.9% of IL-5 positive cells were eosinophils. Only 3.7% of the lymphocytes and neutrophils were IL-5 positive, and IL-5 was not detectable in epithelial cells. IL-5 expression in eosinophils of polyp tissues was remarkably stronger than that of the turbinate mucosa (P < 0.05). There was no significant difference in inferion turbinate mucosa between the patients with nasal polyps and healthy volunteers (P > 0.05). IL-5 expression of eosinophils in polyp tissues was significantly stronger in patients with extensive polypoid change of nasal mucosa, history of previous polypectomy and allergic rhinitis compared with those without these features (P < 0.05). There was no significant difference in IL-5 expression in lymphocytes and neutrophils between polyp tissues and inferior turbinate nasal mucosa (both P > 0.05).
Conclusion: IL-5 is a key protein in eosinophilic pathologic mechanisms in nasal polyp tissues.