Th2-type cytokines are powerful activators of the production of antibodies by B cells, specially IgE, through the stimulation of IL-4 and IL-13 [31], a process that can be particularly important in the pathophysiology of EoE, we have evidence for in situ IgE production and class switching to IgE in the esophageal mucosa of EoE patients [32], which appears to be present into the esophageal epithelium linked to the surface of activated mast cells [33-37]. This evidence concerns the gene IL4 and eosinophilic esophagitis.