Involvement of interleukin-18 in the pathogenesis of human eosinophilic esophagitis

Food allergy is one of the major causes that promote EoE; therefore, we tested the hypothesis that IL-18 is involved in food allergen-induced EoE pathogenesis. Accordingly, we examined normal SPT+ and SPT− EoE patient blood and biopsy samples for IL-18, IL-18Rα, ICAM and VCAM expression Herein, we show increased IL-18 level is highly significant in food allergen SPT+ compared to SPT− EoE patients. We also report that IL-18Rα+ cells and mRNA levels are induced in the esophageal biopsies of EoE patients and blood IL-18 levels correlate with esophageal eosinophilia (p<0.01). Additionally, we report that the levels of esophageal eosinophil and mast cells correlate with ICAM expression in human EoE. Mechanistically, we show that IL-18 in vitro stimulates iNKT cells and endothelial cells and induce eosinophil active cytokines IL-5, IL-13. We provide the evidence that IL-18 is critical cytokine involved in activation of iNKT cells and ICAM in promoting human EoE..