Gene Expression Patterns in Distinct Endoscopic Findings for Eosinophilic Gastritis in Children

Background: Eosinophilic gastritis (EG) is clinicopathologically characterized by both marked gastric eosinophilia and clinical symptoms. The endoscopic findings in EG vary among patients, leading to clinical confusion. However, little is known about the relationship between precise endoscopic findings and the pathophysiological process responsible for EG. Objective: We aimed to elucidate whether the gross endoscopic findings of EG can be classified into distinct gene expression profiles. Methods: We enrolled pediatric patients who underwent gastrointestinal endoscopy for clinical symptoms suggestive of eosinophilic gastrointestinal disorder between 2011 and 2016. EG was diagnosed when gastric eosinophilia was greater than or equal to 30 eosinophils/hpf. The gene expression profiles of gastric biopsies were assessed using microarray technology. Results: Patients with EG and control subjects (n = 8, each) were examined. On the microarray, 1,999 genes were differentially expressed between EG and the controls (≥2-fold difference, adjusted P value < .05), including significant upregulation of eotaxin-3 (C-C chemokine ligand 26). The endoscopic findings of patients with EG fell roughly into 2 types, namely, ulcerative and nodular lesions. Despite identifying distinct patterns of gene expression, most differentially regulated genes overlapped between the 2 endoscopic finding types. Several gene ontology terms were enriched in the substantially overlapped genes, but not in each of the distinct genes. Conclusions: Our results strongly indicate that ulcerative and nodular lesions are a single disease, EG, or a variation thereof, in spite of morphological differences. Our findings may contribute to a better understanding of the pathogenesis of EG, as well as to more accurate diagnosis of this disease.