Su1123 Milk-Specific Immunoglobulin Free Light Chain Secretion Is Increased in Children With Eosinophilic Esophagitis

Abstract

Background: Eosinophilic esophagitis (EoE) is an esophageal inflammatory disease caused by multiple food triggers. The mechanism by which foods trigger EoE is unknown. Milk is by far the most common trigger. Standard allergy tests to milk (skin prick tests, atopy patch tests, and serum milk-specific IgE) have not been predictive. Immunoglobulin free light chains (IgfLC) were shown to be elevated in allergic diseases in an antigen-dependent manner and independently from serum IgE levels. We sought to investigate whether milk-specific IgfLC secretion is increased in children with EoE. Methods: Serum samples from 40 children with EoE, 11 inflammatory controls (gastroesophageal reflux disease or GERD) and 11 non-inflammatory controls (normal esophageal histology) were retrieved, following their identification from a research database at the Mount Sinai Center for Eosinophilic Disorders that includes age and atopic status. Serum milk-specific IgfLC levels were determined using an ELISA-based assay in which milk protein concentrate was coated to a plate. Binding of milk-specific IgfLC was detected by κ or λ IgfLC-specific antibodies. Optical density (O.D.) values for milk-specific κ and λ IgfLC were recorded and compared among the 3 groups. In addition, serum milk-specific IgE levels were measured in all subjects using a fluoroenzyme immunoassay. P