Esophageal String Test in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an increasingly recognized rare disease of children and
adults characterized by symptoms including nausea, vomiting, abdominal pain, dysphagia and
food impaction that occur in conjunction with esophageal eosinophilia. To date, the only
method to make EoE diagnoses and follow treatment responses in EoE is invasive endoscopy with
biopsy. While endoscopy is generally safe, an accurate, less invasive, inexpensive,
comprehensive and durable test is urgently needed to determine therapeutic efficacy. To
address this need, the investigators will use a novel application of an existing technology,
the Enterotest™ (a string-based test used to detect intestinal Giardiasis), to measure
esophageal inflammation (herein termed the Esophageal String Test - EST). The investigators
supportive Preliminary Data provide proof-of-principle for the ability of ESTs to capture
esophageal inflammatory mediators in luminal samples from patients affected with EoE. The
investigators prospective study demonstrates that: (1) levels of eosinophil-derived granule
proteins (MBP1, EDN, ECP, EPX, CLC/Gal-10) in esophageal mucosal biopsies correlate with
levels quantitated in EST-captured samples, i.e., levels in luminal secretions captured by
the EST correlate with mucosal inflammation, and (2) these luminal biomarkers of eosinophilic
inflammation significantly correlate with EoE disease activity. These findings provide strong
support for using ESTs as novel minimally invasive instruments to monitor therapeutic
efficacy in EoE. The global objective of this project is therefore to bring the "Esophageal
String Test" (EST) to commercialization, so that it can be used to monitor therapeutic
efficacy in children and adults with EoE. The investigators hypothesize that ESTs will
capture an EoE Biomarker Panel (EBP) reflective of disease activity. The Specific Aims are
to: (1) Identify an EoE Biomarker Panel (EBP) that will improve the sensitivity and
specificity of the EST for monitoring disease activity and (2) Validate the ability of the
EST EBP to monitor therapeutic efficacy in 1-hour sampling time. The investigators supportive
Preliminary Data demonstrate the feasibility of using ESTs in both children and adults with
EoE to measure disease activity (esophageal inflammation) in an overnight (12-hour) test, and
shorter time periods, currently performed before a scheduled endoscopy with biopsy. In this
project, The investigators propose to shorten this time frame to a 1-hour test, a clinically
relevant time point that will markedly facilitate its use and potential impact in the
outpatient clinic setting.

Public Health Relevance/Impacts: At least four major impacts should result from these
studies:

(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.

Inclusion Criteria:

- Patients undergoing esophagogastroduodenoscopy (EGD) at Children's Hospital Colorado,
or

- Patients from a participating site in whom an inflammatory GI disease is suspected.

- Patients with symptoms of:

1. abdominal pain,

2. vomiting,

3. growth delay, or

4. malabsorption for which an etiology has not been determined.

- Patients with chronic eosinophilic esophagitis (EoE) in whom symptoms suggest ongoing
inflammation.

Exclusion Criteria:

- Patients suffering from bleeding diathesis, or any other comorbid condition which
their doctor feels may put them at additional risk.

- Patients with a family history of connective tissue disease.

- Patients undergoing a therapeutic endoscopy (such as dilatation, sclerotherapy,
variceal banding).

- Patients with a history of:

1. esophageal stricture, or

2. surgery such as fundoplication, or

3. allergy to gelatin, or

4. inability to swallow pills.