Purpose: Previous data have suggested that Filaggrin (FLG) gene may be dysregulated in eosinophilic esophagitis (EoE). We aimed to further evaluate the expression patterns of FLG protein in esophageal tissue samples of pediatric patients with EoE, as compared to those of normal controls. Patients and methods: During the period from September 2018 to February 2021, a total of 970 prospectively collected pediatric cases aging from 1 to 13 years including 474 females and 496 males that presented to our tertiary care center for upper gastrointestinal symptoms that necessitated upper gastrointestinal endoscopy and biopsy were included in our study. The immunohistochemical expression of Filaggrinwas evaluated in esophageal biopsies obtained from patients and controls, and the results were correlated with EoE-related clinicopathological parameters. Results: There were 970 patients in this research. Primaryeosinophilic esophagitis represented 1.9 percent of the subjects included in this study and hadsignificantly lowerFilaggrin expression.All endoscopic results improved considerably following therapy, as did the symptoms and the expression of Filaggrinwas dramatically increased. Conclusion:When compared to normal controls, the immunohistochemistry expression of Filaggrinwas downregulated in the esophageal mucosa of children with EoE in our research. Following therapy, the aforesaid changes were reversed in a statistically significant percentage of instances.

eosinophilic esophagitis; immunohistochemistry; Filaggrin; esophageal eosinophilia.