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Show 48 Allergy testing (e.g., skin prick testing, IgE antibody testing, or atopy patch testing) cannot be used to identify foods that trigger EoE [8]. We previously found that IgG4, not IgE, is increased in tissue homogenates from EoE [9]. This finding has been corroborated by other groups [10, 11, 12, 13, 14, 15]. Wright et al. showed that food-specific IgG4 was associated with active EoE and became undetectable after resolution in a small patient cohort [10]. It is still unclear whether the detection of food-specific IgG4 is an accurate predictor of food antigens that trigger EoE. EoE is associated with disruption in epithelial barrier function [16]. As a result, foodspecific IgG4 could enter the secretions of the esophagus. IgA is secreted into the esophageal lumen and mediates mucosal immunity [17]. Diagnostic tests for antigen-specific IgA have been used for other disorders, such as celiac disease [18]. However, whether a food-specific IgA response occurs in EoE is unknown. We previously showed that esophageal secretions can be collected by an endoscopic cytobrush [19]. Compared to biopsy, esophageal brushing is less invasive and allows secretions to be collected from a larger surface area. Due to the focal nature of lesions in EoE, sampling a larger surface area may increase the likelihood of detecting food-specific antibodies . In this study, we hypothesize that esophageal secretions from patients with active EoE contain IgG4 and/or IgA against disease-triggering foods, and that these food-specific antibodies (FSAs) are not produced in treatment-resolved EoE patients or controls. Together, these results would suggest that (FSAs) in esophageal secretions could be used as biomarkers to predict food triggers for EoE, guide therapeutic diet elimination, and monitor treatment response. 5.3 5.3.1 Methods Study design This prospective observational study was conducted under IRB 00052527 at the University of Utah. Patients were offered enrollment if they met either of two criteria: 1) no prior diagnoses of esophageal disorders that required endoscopy due to dysphagia, or 2) previously diagnosed EoE presenting for a follow-up endoscopic biopsy in order to assess disease status. Patients diagnosed with other gastrointestinal immunologic disorders were |
