Association between increased duodenal eosinophil count and functional dyspepsia

BACKGROUND: Functional dyspepsia (FD) is a common gastrointestinal disorder with multifactorial pathogenesis. Recent evidence suggests that duodenal eosinophilia may contribute to low-grade immune activation in FD. This study evaluated the association between increased duodenal eosinophil count and functional dyspepsia. MATERIALS AND METHODS: This case-control study was conducted in the Department of Gastroenterology, Sir Salimullah Medical College, Mitford Hospital, Dhaka, Bangladesh, from January to December 2022. Forty-six adult patients with functional dyspepsia diagnosed by Rome-III criteria were included as cases, while forty age- and sex-matched individuals without functional dyspepsia undergoing upper gastrointestinal endoscopy for other indications with normal endoscopic findings served as controls. Multiple biopsies were obtained from the second part of the duodenum. Formalin-fixed paraffin-embedded tissue sections were stained with hematoxylin and eosin. Eosinophils were counted manually by light microscopy in five randomly selected high- power fields (x 400 magnification), and the mean eosinophil count per high-power field (HPF) was calculated. RESULTS: The mean duodenal eosinophil count was significantly higher in patients with functional dyspepsia compared with controls (23.98 ± 7.98 versus 15.63 ± 5.94 eosinophils/HPF, p <0.001). Duodenal eosinophilia (≥21 Eosinophils/HPF) was present in 69.6% of patients with functional dyspepsia compared with 17.5% of controls. Increased duodenal eosinophil count was significantly associated with functional dyspepsia (odds ratio 9.74, 95% confidence interval 3.50-27.08). CONCLUSIONS: Patients with functional dyspepsia demonstrated significantly greater duodenal eosinophil infiltration than controls, supporting the role of low-grade immune activation in its pathogenesis. Further multicenter studies with larger samples are required to clarify the clinical implications of duodenal eosinophilia in functional dyspepsia.