Is Mast Cell Infiltration Associated with a Reduced Response to Proton Pump Inhibitors in Pediatric Eosinophilic Esophagitis

Summary: The variability of response to proton pump inhibitor (PPI) therapy in eosinophilic esophagitis (EoE) is poorly understood. It is well known that intraepithelial mast cell numbers are increased in EoE; however the role of mast cells and associated epithelial changes as a predictor of treatment response in EoE has yet to be established. We examined mast cell burden in esophageal biopsies of pediatric subjects with PPI-responsive (PPI-R) EoE, PPI-nonresponsive (PPI-NR) EoE, and non-EoE esophageal dysfunction (controls). Although CD117 counts did not differ between PPI-R and PPI-NR EoE at baseline, subjects with PPI-NR EoE had higher expression of TPSB2 and CPA3 genes compared to PPI-R EoE. Mast cell activation may help identify PPI-R and PPI-NR EoE prior to treatment. Additional research is warranted to assess the role of mast cell activation on PPI effectiveness in EoE.