Interleukin-17A expression in patients with chronic rhinosinusitis and its relationship with clinical features

Objective To investigate the expression of interleukin (IL) 17A in Chinese patients with chronic rhinosinusitis (CRS) and analyse its correlation with clinical parameters. Methods Patients undergoing functional endoscopic sinus surgery and matched controls were included in this retrospective study. Clinical assessments (using a visual analogue scale of symptom severity, Johansson endoscopic score and Lund–Mackay computed tomography score) were performed preoperatively. Mucosal specimens were analysed for inflammatory infiltration and IL-17A expression, using immunohistochemistry. Results In total, 40 patients undergoing functional endoscopic sinus surgery and 16 controls were included in the study. IL-17A levels were significantly higher in tissues from patients with CRS (with or without nasal polyps) than in control tissues. In CRS, IL-17A expression tended to be higher in tissues with infiltrating neutrophils than in those with infiltrating eosinophils, but this difference was not significant. IL-17A expression in CRS was positively correlated with symptom severity, endoscopic findings and radiological appearance. Conclusions Expression of IL-17A was higher in Chinese patients with CRS than in controls, and was associated with infiltrating inflammatory cells, symptom severity, endoscopic findings and radiological appearance. These findings suggest that IL-17A may play a role in CRS pathogenesis and remodelling of nasal polyps.