Periostin has been shown to be upregulated in the subepithelial region in asthma (10), AD (37, 49), allergic conjunctivitis (AC) (52), eosinophilic esophagitis (EoE) (31) and familial idiopathic pulmonary fibrosis (IPF) (47, 48). This evidence concerns the gene POSTN and eosinophilic esophagitis.