Eosinophilic inflammation in intrinsic asthma

Mayo Clinic Coll Of Medicine, Rochester, Rochester MN

Investigators

Linked publications & trials

Abstract

Description (provided by applicant): Toward the achievement of the overall goal of this AADRC, Project 3 "Eosinophilic Inflammation in Intrinsic Asthma" will address why eosinophilia inflammation persists in the airways of patients with asthma and what significance eosinophil degranulation has in the disease process of human asthma. Bronchial mucosal abnormalities that characterize asthma, such as persistent airway eosinophilia and increased T cells producing IL-5, strongly suggest an ongoing T helper (Th)2-like immune response of the airways. Atopy and an IgE-mediated response to extrinsic antigens are the known and identifiable predisposing factors for asthma. However, many adult patients with asthma do not seem to be particularly atopic. The objective of this project is to elucidate the causes and pathophysiologic mechanisms of asthma in patients that are not demonstrably atopic, a condition commonly referred to a non-atopic or intrinsic asthma. We will test the hypothesis that bronchial asthma in patients with non-atopic asthma is caused by a chronic immunologic reaction to intrinsic antigen, namely fungi present in the airways, resulting in persistent IL-5 production and eosinophil activation in the airways. In Specific Aim 1, we will define the enhanced immunological responses, especially IL-5 and IFN-gamma production, of patients' immune cells to non-pathologic fungal organisms present in the airways. In Specific Aim 2, we will directly test whether fungal organisms present in the airways are involved in the disease process by removing the fungi from the airways by instillation of an antifungal agent. Conversely, the effects of an increased fungal antigen burden will be investigated by segmental broncho-provocation. In Specific Aim 3, we will use novel antibodies that recognize eosinophil degranulation activities to define the clinical relevance of eosinophil activation in human asthma by testing the hypothesis that enhanced eosinophil activation and degranulation in the airway lead to exacerbation of asthma symptoms in patients with non-atopic asthma. Elucidation of the causes and mechanisms of inflammation in non-atopic asthma will likely foster a better understanding of eosinophilia inflammation in human asthma and will enhance development of specific and effective therapies for this difficult disorder.