Abstract

Proton Pump Inhibitors Therapy for Eosinophilic Esophagitis

Javier Molina-Infante, Jose Zamorano, Maria D. Rivas and Miguel Fernandez-Bermejo

Proton pump inhibitors (PPIs) are the pharmacological cornerstone for acid-related peptic disorders, especially gastroesophageal reflux disease (GERD), on account of their powerful suppression of gastric acid secretion. GERD is the most common esophageal disease, with approximately 10-20% of adult Western population affected, mainly males between 20 and 50 yrs-old. Eosinophilic esophagitis (EoE) is an emerging immuno/antigen-mediated disorder, characterized by esophageal symptoms and eosinophil-predominant inflammation. It is an allergic condition of growing recognition and prevalence, so much so that it is currently recognized as the second cause of chronic esophagitis after GERD. EoE usually presents in allergic males under 40 yrs-old, so GERD and EoE coexist frequently in adult patients. Initially, both disorders were distinguished since EoE was, by definition, unresponsive to PPIs. However, case reports and small series since 2006 have progressively shown patients with clinical, endoscopic and histological data consistent with EoE having complete remission on PPIs. Notwithstanding the fact that these patients have been historically classified as having mislabelled GERD, recent evidence has made way for a new potential phenotype of EoE (PPI-responsive esophageal eosinophilia), even in patients with normal acid exposure. Furthermore, more confusion has been added to the debate since GERD has been recently redefined as a cytokinemediated disorder rather than acid-injury mediated. As such, PPIs might also affect GERD-related or EoE-related esophageal eosinophilia through immunomodulatory mechanisms beyond acid suppression. This report intends to update the available evidence on PPI-responsive esophageal eosinophilia and briefly review the mechanisms whereby PPIs might exert potential anti-inflammatory effects on allergic diseases such as EoE.