An elevated TGF-β expression has repeatedly been found in esophageal biopsy samples of patients with active EoE (Aceves et al., 2007; Mishra et al., 2008; Straumann et al., 2010a), especially in mast cells (Aceves et al., 2010a). This evidence concerns the gene TGFB1 and eosinophilic esophagitis.