A striking local esophageal cytokine expression profile in eosinophilic esophagitis

Abstract

Background Eosinophilic esophagitis (EE) is an emerging worldwide disease that mimics gastroesophageal reflux disease. Objective Early studies have suggested that esophageal eosinophilia occurs in association with T helper type 2 allergic responses, yet the local and systemic expression of relevant cytokines has not been well characterized. Methods A human inflammatory cytokine and receptor PCR array containing 84 genes followed by PCR validation and multiplex arrays were used to quantify cytokine mRNA in esophageal biopsies and blood levels. Results Esophageal transcripts of numerous chemokines [e.g. CCL1, CCL23, CCL26 (eotaxin-3), CXCL1, and CXCL2], cytokines (e.g. IL13 and ABCF1), and cytokine receptors (e.g. IL5RA) were induced at least 4-fold in individuals with EE. Analysis of esophageal biopsies (n=288) revealed that eotaxin-3 mRNA level alone had 89% sensitivity for distinguishing EE from non-EE individuals. The presence of allergy was associated with significantly increased esophageal expression of IL4 and IL5 mRNA in active EE patients. We identified 8 cytokines (IL-4, IL-13, IL-5, IL-6, IL-12p70, CD40L, IL-1α, and IL-17) whose blood levels retrospectively distinguished 12 non-EE from 13 EE patients with 100% specificity and 100% sensitivity. When applied to a blinded, prospectively recruited group of 36 patients, the cytokine panel scoring system had a 79% positive predictive value, 68% negative predictive value, 61% sensitivity, and 83% specificity for identifying EE. Conclusion Evidence is presented that IL13 and IL5 associate with eosinophil and eotaxin-3 levels, indicating the key role of adaptive Th2 immunity in regulating eotaxin-3-driven esophageal eosinophilia in the absence of a consistent systemic change in cytokines.