Cellular Changes 24 Hours after Endobronchial Allergen Challenge in Asthma

Asthma Eosinophils Lymphocytes Endobronchial challenge Histology Correspondence to: Dr. A.J. Frew, University of Southampton, Room CD 139, Level D, Centre Block, Southampton General Hospital, Tremona Road, Southampton SO16 6YD (UK) Local endobronchial allergen challenge allows a high dose of allergen to be delivered to a single airways segment to study the release of spasmogenic mediators [1] and recruitment of T cells and other leucocytes in small blood vessels in the subjacent bronchial mucosa [2], in comparison to matched control sites. Six hours after challenge, we found an increased number of eosinophils and neutrophils with up-regulation of the endothelial adhesion molecules ICAM-1 and Eselection [3]. We have extended these studies to address the cellular changes 24 hours after local allergen exposure. caine. Endobronchial challenge was performed in the medial segment, right middle lobe with 20 ml of prewarmed allergen solution, the concentration used being calculated by skin test titration. Control challenge was performed with 20 ml saline diluent in the anterior segment, right upper lobe. The airway was observed for 5 min to confirm bron-choconstriction. A second bronchoscopy was performed with identical premedication 24 h later. Bronchoalveolar lavage (BAL) was performed in each of the challenged segments with 120 ml isotonic warm saline and four mucosal biopsies were obtained from each segment. Mucosal biopsies were processed into glycol methacrylate and stained with monoclonal antibodies and an indirect peroxidase technique. BAL cells were processed for flow cytometry and in a small number of cases, samples were studied by PCR for cytokine transcription.