Background

Esophageal eosinophilia can be proton pump inhibitor (PPI) resistant or responsive, representing 2 entities known as eosinophilic esophagitis (EoE) and PPI-responsive esophageal eosinophilia (PPI-REE), respectively. Although they present with similar clinical features, EoE is accepted to be an antigen-driven, TH2-associated allergic disorder, whereas the cause of PPI-REE remains a mystery.

Objective

In this study, our aim was to investigate the pathogenesis of PPI-REE by using a recently described EoE diagnostic panel (EDP) composed of a set of 94 esophageal transcripts and to determine whether PPI therapy reverses any esophageal transcriptional abnormalities.

Methods

We evaluated the EDP signature in biopsy samples obtained from adult and pediatric patients with PPI-REE from 4 institutions and compared the pre- and post-PPI therapy expression profiles of these subjects with those of patients with active EoE.

Results

The EDP differentiated patients with EoE from control subjects with 100% accuracy among the 4 clinical sites. Bioinformatics analysis revealed largely overlapping transcriptomes between patients with PPI-REE and those with EoE, including the genes for eosinophil chemotaxis (eotaxin 3, CCL26), barrier molecules (desmoglein 1, DSG1), tissue remodeling (periostin, POSTN), and mast cells (carboxypeptidase A, CPA3). PPI monotherapy alone almost completely reversed the allergic inflammatory transcriptome of patients with PPI-REE. Furthermore, we identified a set of candidate genes to differentiate patients with EoE from those with PPI-REE before treatment.

Conclusion

These findings provide definitive evidence that PPI-REE is a disease entity with significant molecular overlap with EoE, suggesting that many patients with PPI-REE represent a continuum of the same pathogenic allergic mechanisms that underlie EoE and thus might constitute a subphenotype of patients with EoE. The ability of PPI therapy to nearly entirely reverse gene expression associated with PPI-REE, particularly that associated with classic features of allergic inflammation, provides new insight into potential disease etiology and management strategies for patients with significant esophageal eosinophilia.

Background & aims

Standardized instruments are needed to assess the activity of eosinophilic esophagitis (EoE) and to provide end points for clinical trials and observational studies. We aimed to develop and validate a patient-reported outcome (PRO) instrument and score, based on items that could account for variations in patient assessments of disease severity. We also evaluated relationships between patient assessment of disease severity and EoE-associated endoscopic, histologic, and laboratory findings.

Methods

We collected information from 186 patients with EoE in Switzerland and the United States (69.4% male; median age, 43 y) via surveys (n = 135), focus groups (n = 27), and semistructured interviews (n = 24). Items were generated for the instruments to assess biologic activity based on physician input. Linear regression was used to quantify the extent to which variations in patient-reported disease characteristics could account for variations in patient assessment of EoE severity. The PRO instrument was used prospectively in 153 adult patients with EoE (72.5% male; median age, 38 y), and validated in an independent group of 120 patients with EoE (60.8% male; median age, 40.5 y).

Results

Seven PRO factors that are used to assess characteristics of dysphagia, behavioral adaptations to living with dysphagia, and pain while swallowing accounted for 67% of the variation in patient assessment of disease severity. Based on statistical consideration and patient input, a 7-day recall period was selected. Highly active EoE, based on endoscopic and histologic findings, was associated with an increase in patient-assessed disease severity. In the validation study, the mean difference between patient assessment of EoE severity (range, 0-10) and PRO score (range, 0-8.52) was 0.15.

Conclusions

We developed and validated an EoE scoring system based on 7 PRO items that assess symptoms over a 7-day recall period. Clinicaltrials.gov number: NCT00939263.