Inflammatory characteristics in different types of nonallergic rhinitis

Objective: Nonallergic rhinitis (NAR) is classified on the basis of the eosinophil (EOS) level. Our study aimed to describe the inflammatory characteristics in different types of nonallergic rhinitis. Methods: In our study, 12 patients with allergic rhinitis (AR), 10 patients with nonallergic rhinitis with eosinophilia syndrome (NARES), 12 patients with nonallergic rhinitis without eosinophilia, and 11 healthy participants were enrolled from May 2016 to July 2016. We assessed the inflammatory characteristics by using skin prick testing (SPT) and determinedthe nasal/ serum cytokine levels and regulatory T cells (Tregs) in the peripheral blood. Results: The nasal IL-4 (42.27 +/- 22.10 vs. 24.93 +/- 8.90) and IL-17 (25.51 +/- 5.11 vs. 16.80 +/- 4.92) levels, as well as the serum IL-4 (49.87 [24.76-101.35] vs. 20.92 [9.40-29.87]) and IL-17 (31.07 [22.14-96.41] vs. 21.85 [18.55-26.46]) levels were higher in the NARES group than in the control group (P < 0.05). The nasal IL-10 (3.65 [3.45-4.03] vs. 4.16 [3.55-4.27]) levels and the proportion of Tregs in the peripheral blood ([5.0 +/- 1.8)% vs. [6.5 +/- 1.0]%) were lower in the NARES group than in the control group (P < 0.05). There were no significant differences between the AR group and the NARES group or between the NAR without eosinophilia group and the control group (P > 0.05). Conclusions: Nonallergic rhinitis was classified on the basis of the EOS level, and the two types of NAR had different pathogenesis of inflammation and inflammatory manifestations. Further, NARES and AR had similar pathogenesis of inflammation, which resemble the Th2 and Th17 inflammatory characteristics. Therefore, it would be more logical to determine the classification of rhinitis on the basis of EOS level.