Immunopathogenesis of Food Allergy and Eosinophilic Gastrointestinal Disorders

Food allergy refers to a number of disorders characterized by clinical diseases associated with abnormal immune responses to food antigens. Classical IgE mediated anaphylactic food allergy is characterized by immediate hypersensitivity, and has a prevalence of approximately 6% and 3% in children and adults, respectively. In contrast, eosinophil associated gastrointestinal disorders (EGIDs), including eosinophilic esophagitis (EoE) and eosinophilic gastroenteritis (EG), are food allergy associated disorders characterized by eosinophilic inflammation of the gut, typically without anaphylaxis. Progress in the treatment and management of these food allergies requires further understanding of the immunological pathogenesis of these disorders. A subset of peripheral blood food allergen specific interleukin (IL) -5 producing T cells that are present in EGID but not peanut allergic subjects has recently been characterized. The primary objective of this study is to determine if similar IL-5 producing T cells are present in the gut of EGID subjects. To this end, both EGID and healthy non-allergic subjects will be enrolled and gastrointestinal biopsies will be obtained for intracellular cytokine staining, RT-PCR and ELISA. Additionally, this protocol will supply blood and leukapheresis samples for exploratory studies on immunologic mechanisms underlying anaphylactic food allergy and EGIDs. A total of up to 400 subjects recruited from outside physician referrals and support groups, as well as from those in existing National Institutes of Health (NIH) protocols will be enrolled in this Clinical Center study.