RT Journal Article SR Electronic T1 Allergen-induced airway responses JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 819 OP 831 DO 10.1183/13993003.00536-2015 VO 46 IS 3 A1 Gail M. Gauvreau A1 Amani I. El-Gammal A1 Paul M. O'Byrne YR 2015 UL http://erj.ersjournals.com/content/46/3/819.abstract AB Environmental allergens are an important cause of asthma and can contribute to loss of asthma control and exacerbations. Allergen inhalation challenge has been a useful clinical model to examine the mechanisms of allergen-induced airway responses and inflammation. Allergen bronchoconstrictor responses are the early response, which reaches a maximum within 30 min and resolves by 1–3 h, and late responses, when bronchoconstriction recurs after 3–4 h and reaches a maximum over 6–12 h. Late responses are followed by an increase in airway hyperresponsiveness. These responses occur when IgE on mast cells is cross-linked by an allergen, causing degranulation and the release of histamine, neutral proteases and chemotactic factors, and the production of newly formed mediators, such as cysteinyl leukotrienes and prostaglandin D2. Allergen-induced airway inflammation consists of an increase in airway eosinophils, basophils and, less consistently, neutrophils. These responses are mediated by the trafficking and activation of myeloid dendritic cells into the airways, probably as a result of the release of epithelial cell-derived thymic stromal lymphopoietin, and the release of pro-inflammatory cytokines from type 2 helper T-cells. Allergen inhalation challenge has also been a widely used model to study potential new therapies for asthma and has an excellent negative predictive value for this purpose.Environmental allergens are an important cause of asthma http://ow.ly/NxkGi