IL-17 producing T cells correlate with polysensitization but not with bronchial hyperresponsiveness in patients with allergic rhinitis

Background: Th2-type T cell response has a considerable role in atopic diseases. The involvement of Th17 and IL-17 in atopy process provided new understanding of allergic diseases. Bronchial hyperresponsiveness is quite common in allergic rhinitis. We aimed to explore the expression of IL-17 producing CD3+ CD4+ T cells in peripheral blood of rhinitic patients, with/without bronchial hyperresponsiveness and sensitized to common allergens, as this relationship has not been examined. Methods: Sixty one patients with allergic rhinitis and thirty controls were examined. IL-17 producing T cells were detected by flow cytometry, IL-17, IL-4 and IL-13 levels in peripheral blood were evaluated by ELISA. Bronchial hyperresponsiveness was investigated with methacholine challenge test. Atopy was evaluated by skin prick tests with common allergens. Results: IL-17 producing T cell percentage of AR group was significantly higher: 2.59 +/- 1.32 than in controls 1.24 +/- 0.22, (p = 0.001). Significant sex related difference in CD3+ CD4+ IL-17 T cells was observed: respectively in male patients versus female 3.15 +/- 1.8% and 2.31 +/- 0.9%, (p = 0.02). Rhinitics had greater bronchodilator responses compared to controls (p = 0.001), however the percentages of T cells in both groups appeared equal. Serum IL-17 levels in AR group were significantly higher (5.10 +/- 4.40) pg/ml than in controls (3.46 +/- 1.28) pg/ml, (p = 0.04). IL-4 levels (0.88 +/- 1.27) and IL-13 levels (3.14 +/- 5.85) in patients were significantly higher than in controls (0.54 +/- 0.10) pg/ml, (p = 0.001) and (1.19 +/- 0.64) pg/ml; (p = 0.001) respectively. The percentages of T cells in patients sensitized to 5 allergens (group I) were significantly lower (1.91 +/- 0.62) than those sensitized to more than 5 allergens (group II) (2.91 +/- 1.5) (p = 0.004). Conclusions: The observed higher levels of IL-17 producing T cells in polysensitized males suggest a role of IL-17 in pathogenesis of AR. The higher airway responsiveness in AR may not be Th17 dependent. The higher serum values of IL-17, IL-4 and IL-13 demonstrate the presence of cytokine balance in atopic diseases.