The objective of this study is to determine the performance characteristics of a series of novel, non-invasive allergen-activated T cell assays designed to identify Eosinophilic esophagitis (EoE) causal foods, when used in conjunction with standard-of-care (SOC) practices.

The question it aims to answer is:

Will assay results accurately predict EoE food allergies in concordance with SOC endoscopies after diet changes?

This proof-of-concept, interventional prospective cohort study will enroll subjects with Eosinophilic esophagitis (EoE) who have not yet identified causal foods. Subject blood will be drawn and food-activated T cell responses will be assayed. Subjects will be advised to remove foods based on standard-of-care practices and/or the outcome of their T cell assays ("personalized elimination diet"). Symptoms will be measured by the Pediatric Eosinophilic Esophagitis Symptom Scores (PEESS) Child and Parent Surveys and standard of care (SOC) endoscopy with esophageal biopsy, respectively. Response to research assay-directed diet changes will provide information about the assay's clinical value.

Inclusion Criteria:

Diagnosis of Eosinophilic esophagitis (EoE) based on positive esophageal biopsy (>15 eosinophils/high power field) within three months of enrollment.

AND Intention to undergo dietary intervention for treatment of their EoE. AND Unknown contribution of one or more of milk, soy, egg, and wheat to their EoE disease state.

AND Willingness to adopt an elimination diet based in part on the results of the experimental testing.

Exclusion Criteria:

Proton pump inhibitor (PPI)-responsive EoE: Resolution or response of EoE to high-dose PPI (2 mg/kg) alone, at the PI's discretion.

OR Presence of other inflammatory or infectious gastrointestinal pathology (e.g. eosinophilic gastrointestinal diseases, irritable bowel disease, Infectious Colitis, etc.), at the discretion of the Principal Investigator (PI).

OR Prior medical or surgical history that precludes safely performing an upper endoscopy with biopsy or restriction of diet.

OR Current immunomodulatory therapy >4 weeks (swallowed or systemic steroids, biologic therapy, chemotherapy. etc.) that may interfere with the blood test or biopsy results, at the PI's discretion.

OR Inability to read or understand English.

There is no plan to share individual participant data with other researchers. All data that may be published or shared with other researchers will be deidentified and will not include information such as informed consent forms.