Eosinophil-Derived Neurotoxin Predicts Response to Proton-Pump Inhibitor Treatment in Pediatric Eosinophilic Esophagitis

Objectives: There are no tests or patient factors to help predict the best treatment approach for a patient with eosinophilic esophagitis (EoE). The prevalence of proton-pump inhibitor (PPI) responsive EoE in children ranges from 30% to 71% with multiple studies showing similar characteristics in responders and nonresponders. Eosinophil-derived neurotoxin (EDN), an eosinophilic granule protein, measured in esophageal brushing has been shown to be a viable measure of disease activity in EoE. Our aim is to determine if EDN can help predict response to PPI in pediatric patients with EoE. Methods: We conducted a prospective cross-sectional study to compare EDN between PPI-responsive and PPI-nonresponsive EoE subjects from 2018 through 2020. Enrolled patients with active EoE were treated with high-dose PPI and underwent repeat endoscopy to determine PPI-responsiveness. EDN was measured at baseline endoscopy, before any treatment, and at follow up endoscopy, after PPI therapy. Subjects were divided into PPI-responsive and nonresponsive groups. EDN, endoscopic reference score (EREFS), and peak eosinophilic count (PEC) were compared. Results: Fifteen out of the 36 enrolled subjects with EoE (age range 2-18 years, 73.3% male) were PPI-responsive and 21 (age range 2-19 years, 95.2% male) were PPI-nonresponsive. EDN concentration was significantly higher in the PPI-nonresponsive group than in the PPI-responsive group (219.1 +/- 229 mcg/mL vs 75.7 +/- 60 mcg/mL, respectively, P = 0.036). There was no difference between the two groups in EREFS (P = 0.55) or PEC (P = 0.15). Conclusions: EDN measured in esophageal epithelial samples obtained by brushing during endoscopy may predict PPI-responsiveness in children and young adults with EoE.