(1) Identification of an EBP will permit monitoring of esophageal inflammation in EoE; (2) the EBP will be relevant to following disease progression, treatment responses, management and pathogenesis of EoE, (3) validation of the EST EBP will enable development of rapid and inexpensive assays to follow treatment responses, thus reducing the number of follow-up endoscopies with biopsy that are currently performed, and (4) provide a device to monitor EoE disease activity where endoscopy with biopsy may not be available or affordable.