Major basic protein is a useful marker to distinguish eosinophilic esophagitis from IBD‐associated eosinophilia in children

Objectives The incidence of eosinophilic esophagitis (EoE) is 3−5 times greater in patients with inflammatory bowel disease (IBD) compared with the general population. This study aimed to differentiate true EoE from esophageal eosinophilia in IBD patients by evaluating expression of major basic protein (MBP) and interleukin‐13 (IL‐13) in esophageal biopsies. Methods This retrospective study included subjects who had an esophagogastroduodenoscopy with esophageal biopsies for IBD work up or suspicion for EoE. Patients were classified into 5 groups: EoE with ≥15 eosinophils per high power field (eos/hpf), EoE‐IBD with ≥15 eos/hpf, IBD eosinophilia with 1−14 eos/hpf, IBD and control groups. Biopsies were stained with MBP and IL‐13 antibodies and the results (% staining/total tissue area), demographic, and clinical findings were compared among the groups. Results The median for MBP staining levels in EoE‐IBD was 3.8 (interquartile range 1.3−23), significantly lower than in EoE at 52.8 (8.3−113.2), but higher than in IBD eosinophilia at 0.2 (0−0.9; p