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Background: Seasonal allergic rhinitis could predispose to the development of chronic bronchial inflammation as observed in asthma. However, direct links between nasal inflammation, bronchial inflammation and airway responsiveness in patients with seasonal allergic rhinitis and without asthma are not fully understood. The aim of this study was to analyse the changes induced by allergic nasal challenge outside the pollen season in airway responsiveness and bronchial inflammation of patients with seasonal allergic rhinitis. Methods: Nine patients were evaluated after either grass pollens or placebo nasal challenge in a randomized cross-over double-blinded trial. Nasal parameters were recorded hourly and airway responsiveness was assessed by methacholine challenge. Cytological examinations and cytokine measurements were performed in nasal lavage and induced sputum. Eosinophil activation was investigated by eosinophil-cationic protein expression and secretion. Results: Airway responsiveness was increased after allergic nasal challenge. Total eosinophils and eosinophils expressing eosinophil-cationic protein were increased in induced sputum after allergic nasal challenge. Both eosinophil number and eosinophil-cationic protein concentration in induced sputum were correlated to methacholine responsiveness. Conclusions: These results suggest that eosinophils participate to the bronchial inflammation in patients with seasonal allergic rhinitis following allergic nasal challenge outside the pollen season and might explain changes in airway responsiveness. [ABSTRACT FROM AUTHOR]

Background: We previously showed that patients with severe allergic asthma have high numbers of circulating ILC2s expressing CCR10., Method: Herein, CCR10 + ILC2s were further analyzed in the blood of healthy individuals or patients with allergic and non-allergic asthma. Characteristics of human CCR10 + and CCR10 - ILC2s were assessed by flow cytometry as well as single-cell multiplex RT-qPCR. The role of CCR10 + ILC2s in asthma pathophysiology was studied in allergen-treated mice., Results: When compared to healthy controls, CCR10 + ILC2s are enriched in the blood of both allergic and non-allergic severe asthmatic patients, and these cells are recruited to the lungs. Plasma concentrations of the CCR10 ligand CCL27 are significantly increased in severe asthmatics when compared to non-asthmatic patients. CCR10 + ILC2s secrete little T H 2 cytokines, but exhibit ILC1-like properties, including a capacity to produce IFN-γ. Also, single-cell analysis reveals that the CCR10 + ILC2 subset is enriched in cells expressing amphiregulin. CCR10 + ILC2 depletion, as well as blocking of IFN-γ activity, exacerbates airway hyperreactivity in allergen-challenged mice, providing evidence for a protective role of these cells in allergic inflammation., Conclusions: Frequencies of circulating CCR10 + ILC2s and CCL27 plasma concentrations represent candidate markers of asthma severity. The characterization of CCR10 + ILC2s in human samples and in mouse asthma models suggests that these cells downregulate allergic inflammation through IFN-γ production., (© 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)