Expression of Protease-activated Receptor 2 in Nasal Polyp: Immunohistochemical Study

BACKGROUND AND OBJECTIVES: Protease-activated receptor 2 (PAR-2) has been known to play an important role in modulating homeostasis and inflammation in the airways. But only a little is known about the localization of PAR-2 in nasal mucosa and relationship between PAR-2 and nasal mucosal inflammation. In this study, we investigated the localization of PAR-2 in nasal polyp and turbinate mucosa and examined the relationship between the PAR-2 expression and eosinophil infiltration. MATERIALS AND METHOD: Nasal polyp tissues were obtained from 20 nasal polyposis patients and inferior turbinate tissues were taken from 12 nasal septal deviation patients as control. PAR-2 expression was assessed by immunohistochemical staining. We compared PAR-2 immunoreactivity between nasal polyp and turbinate mucosa. Infiltrated eosinophils were counted ands its correlation with the intensity of PAR-2 immunoreactivity in nasal polyp was determined. Also, we evaluated the PAR-2 expression in the presence of allergic rhinitis. RESULTS: PAR-2 immunoreactivity was detected in the nasal mucosal epithelium, endothelial cells, vascular myocytes, submucosal glands, fibroblasts and inflammatory cells. PAR-2 expression was similar between nasal polyp and turbinate mucosa, but inflammatory cells of nasal polyp showed stronger immunoreactivity than those of turbinate. Immunoreactivity in inflammatory cells showed correlation with eosinophil infiltration in nasal polyp. There were no differences in the PAR-2 expression between allergic rhinitis patients and non-allergic rhinitis patients. CONCLUSION: Increased expression of PAR-2 in inflammatory cells of nasal polyp and its correlation with eosinophil infiltration raise the possibility that PAR-2 may play a role in pathophysiology of nasal polyposis