Published Online: September 25, 2014
Many different cells—including eosinophils, lymphocytes, and dendritic cells—contribute to the inflammatory process in asthma, accumulating in the patients’ lungs. When a person inhales allergens (antigens) like pollen, house dust mite, or cat dander, among many others, dendritic cells (DCs) capture these particles in the airways and migrate to the lymph nodes located adjacent to the lungs. Inside the lymph nodes the DCs then activate lymphocytes and initiate a specific immune response. Until now, only research performed in animal models of allergic airways disease that mimic human asthma had investigated this process in the bronchopulmonary lymph nodes.
In a recent study published in the Journal of Allergy and Clinical Immunology, Cagnoni and colleagues investigated whether there were more dendritic cells, lymphocytes, eosinophils, inflammatory cytokines, and an adhesion molecule in the bronchopulmonary lymph nodes and airways of patients that had died due to a severe asthma exacerbation. The authors also examined whether the eosinophils infiltrating the lungs and lymph nodes of asthmatics could potentially present antigens by expressing co-stimulatory molecules, a very specialized function of DCs.
Results of this study showed that only eosinophils accumulated in the lymph nodes of the asthmatics subjects. In the airways there were increased eosinophils, T and B lymphocytes, and Factor XIIIa+ DCs. Importantly, eosinophils in both the lymph nodes and airways of asthmatics expressed human leukocyte antigen DR (HLA-DR), and the co-stimulatory molecules CD40 and CD80, supporting the idea that eosinophils might be able to present antigens during a fatal asthma exacerbation.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.