Allergen Challenge for Evoked Phenotypes in Asthma (the ACE Study)

This protocol outlines a single-site mechanistic study aiming to investigate long RNAs differentially expressed in the airway epithelium of asthma patients both at baseline and in response to segmental airway allergen challenges. Over approximately 14 days, the study spanned three visits: Visit 1: Comprehensive characterization of participants, encompassing lung function testing, methacholine challenge testing, and allergen skin prick testing. Visit 2: Participants underwent bronchoscopy wherein three procedures were performed a. Epithelial brushings were performed in a segmental airway (baseline sample) b. Diluent (inactive control) was instilled into another segmental airway c. A small dose of allergen was administered into a third segmental airway using standardized cat or dust mite allergen extracts. Visit 3 (24 hours or 7 days post Visit 2): Another bronchoscopy was carried out to collect epithelial brushings in the diluent challenged and allergen challenged segments The collected epithelial brush samples underwent analysis for mRNA expression in the epithelial brushings. The study successfully incorporated a total of 23 subjects, which included 18 asthmatics (with stable or well-controlled conditions), 2 allergic non-asthmatics, and 3 non-allergic non-asthmatics.