Blood Eosinophils Are Accurate Biomarkers for the Management of Eosinophilic Oesophagitis: Prospective, Multi‐Centre Study

Background & Aims: The diagnosis and follow-up of eosinophilic oesophagitis (EoE) currently rely on repeated upper endoscopies (EGD) with biopsies, which are invasive, resource-intensive and environmentally costly. Non-invasive biomarkers for EoE are needed. We investigated the role of blood eosinophils and lymphocytes in the management of EoE. Methods: This was a prospective study conducted at four EoE referral centres. Consecutive adults undergoing EGD with biopsies for known or suspected EoE were enrolled. Based on oesophageal peak eosinophil count (PEC) and clinical history, patients were divided into EoE (histologically active or in remission) and non-EoE dysphagia (NED). Prior to the EGD, a full blood count was obtained. Clinical, endoscopic and histologic findings were recorded. Receiver operating characteristic curve analysis was used to assess the predictive ability of blood biomarkers (AUC). Results: We enrolled 209 patients (123 EoE and 86 NED). For the diagnosis of EoE, an absolute eosinophil count (AEC) of 155 eosinophils/mm3 had an AUC of 85%. For the assessment of histological disease activity, an AEC of 325 eosinophils/mm3 had an AUC of 70.5% for the identification of histological remission following treatment. AEC showed a positive correlation with PEC on histology and the EoE endoscopic reference score with Spearman's Rho of 0.4 (p < 0.0001). Conclusion: Eosinophil absolute and relative counts in the peripheral blood could be used in the initial assessment of patients presenting with dysphagia to accurately differentiate EoE from NED and to predict histological remission of EoE.