Esophageal Eosinophilia Treated With Long-Duration Proton Pump Inhibitor Therapy

Proton Pump Inhibitor Therapy for Eosinophilic Esophagitis: History, Mechanisms, Efficacy, and Future Directions

Over the past decade, the role of proton pump inhibitor (PPI) medication has evolved from a diagnostic tool for Eosinophilic Esophagitis (EoE), by excluding patients with PPI responsive esophageal eosinophilia (PPI-REE), to a therapy for EoE. This transition resulted from the Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the Appraisal of Guidelines for Research and Evaluation II (AGREE) Conference to support PPI therapy for EoE in children and adults. Additional recent advances have suggested a role for genetic variations that might impact response to PPI therapy for EoE. This review article will explore a brief background of EoE, the evolution of PPI therapy for EoE and its proposed mechanisms, efficacy and safety in children and adults, and considerations for future PPI precision medicine in patients with EoE.

Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the AGREE Conference

BACKGROUND & AIMS

Over the last decade, clinical experiences and research studies raised concerns regarding use of proton pump inhibitors (PPIs) as part of the diagnostic strategy for eosinophilic esophagitis (EoE). We aimed to clarify the use of PPIs in the evaluation and treatment of children and adults with suspected EoE to develop updated international consensus criteria for EoE diagnosis.

METHODS

A consensus conference was convened to address the issue of PPI use for esophageal eosinophilia using a process consistent with standards described in the Appraisal of Guidelines for Research and Evaluation II. Pediatric and adult physicians and researchers from gastroenterology, allergy, and pathology subspecialties representing 14 countries used online communications, teleconferences, and a face-to-face meeting to review the literature and clinical experiences.

RESULTS

Substantial evidence documented that PPIs reduce esophageal eosinophilia in children, adolescents, and adults, with several mechanisms potentially explaining the treatment effect. Based on these findings, an updated diagnostic algorithm for EoE was developed, with removal of the PPI trial requirement.

CONCLUSIONS

EoE should be diagnosed when there are symptoms of esophageal dysfunction and at least 15 eosinophils per high-power field (or approximately 60 eosinophils per mm²) on esophageal biopsy and after a comprehensive assessment of non-EoE disorders that could cause or potentially contribute to esophageal eosinophilia. The evidence suggests that PPIs are better classified as a treatment for esophageal eosinophilia that may be due to EoE than as a diagnostic criterion, and we have developed updated consensus criteria for EoE that reflect this change.

Diagnosis and Treatment of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a new disease. It is caused by a T-helper type 2 cell response to food antigens in contact with the esophageal mucosa. Although no single feature defines EoE, a constellation of compatible demographic, clinical, endoscopic, and histologic findings establish the diagnosis. Children present with symptoms and endoscopic patterns characteristic of inflammation, whereas adolescents and adults have manifestations of fibrosis and gross esophageal strictures. Clinical and endoscopic scoring systems have helped to standardize diagnosis. There is controversy in EoE research over the optimal endpoint for treatment. Although the most common endpoint is a reduced number of eosinophils in biopsies, changes in symptoms and endoscopic features are becoming important targets of therapy. We should improve our understanding of EoE progression and the need for maintenance therapy, and continue development of diagnostic tools that avoid endoscopy and biopsy analyses to more easily monitor disease activity.

Proton pump inhibitor-responsive esophageal eosinophilia: still a valid diagnosis?

PURPOSE OF REVIEW

To update rapidly evolving concepts regarding the controversial entity of 'proton pump inhibitor (PPI)-responsive esophageal eosinophilia,' referring to patients with clinical, endoscopic and histologic features of eosinophilic esophagitis (EoE) who achieve remission on PPI therapy.

RECENT FINDINGS

Up to half of pediatric and adult patients with typical EoE symptoms and histology achieve clinico-pathologic remission on PPI therapy, irrespective of whether esophageal pH monitoring demonstrates abnormal acid reflux. In patients with clinical and histologic features of EoE, genotypic and phenotypic features of PPI responders and nonresponders are virtually indistinguishable, and different from those of patients with gastroesophageal reflux disease. In PPI responders, PPIs effects on esophageal Th2 inflammation and gene expression are similar to those of topical steroids in PPI nonresponders. These therapies, along with diets, recently have been shown to be potentially interchangeable in two small series.

SUMMARY

Proton pump inhibitor-responsive esophageal eosinophilia is an inappropriate disease descriptor, arbitrarily based on a response to a single drug, and should be abandoned. Patients who have esophageal eosinophilia and esophageal symptoms that resolve with PPI therapy have phenotypic, molecular, mechanistic, and therapeutic features indistinguishable from similar patients who do not respond to PPIs. These patients with PPI responsiveness should be considered within the spectrum of EoE.