Interleukin 17 and RANTES levels in induced sputum of patients with allergic rhinitis after a single nasal allergen challenge

Background: Interleukin 17 (IL-17) is produced by T, 17 cells and was recently implicated in the development of the T,2 cell response. RANTES (regulated on activation of normal T cells expressed and secreted), among other chemokines, plays a crucial role in chemotaxis of eosinophils into airway mucosa. According to the "united airway" hypothesis, markers of inflammation in allergic diseases are elevated in the upper and lower airways. Objective: To assess the impact of a single nasal allergen challenge on IL-17 and RANTES levels in induced sputum of patients with allergic rhinitis (AR). Methods: Eighteen patients with a history of AR due to grass pollen confirmed by positive skin prick test results and 10 control subjects entered the study. Initially, all the patients underwent sputum induction. A single nasal placebo challenge was performed 24 hours later, with repeated sputum induction 24 hours after challenge. After 4 weeks of washout, these procedures were repeated with allergen challenge. Differential cell counts in sputum were determined, and concentrations of IL-17 and RANTES were measured by means of enzyme-linked immunosorbent assay. Results: Levels of IL-17 and RANTES significantly increased in sputum of patients with AR after allergen (but not placebo) challenge (P=.03 and P=.007, respectively). Postallergen levels of both cytokines in sputum were positively correlated (r = 0.570, P=.02). Allergen challenge led to increased total inflammatory cell (P=.005) and eosinophil (P=.03) counts in induced sputum of patients with AR. Conclusions: Nasal allergen challenge induces the enhanced secretion of IL-17 and RANTES in the lower airways of nonasthmatic patients with AR. Ann Allergy Asthma Immunol. 2009; 103:418-424.