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

Abstract

Interleukin 17 (IL-17) is produced by T(H)17 cells and was recently implicated in the development of the T(H)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. 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). 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. 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. Nasal allergen challenge induces the enhanced secretion of IL-17 and RANTES in the lower airways of nonasthmatic patients with AR.