Intestinal immune activation in presumed post-infectious functional dyspepsia

Area of Science:

• Gastroenterology
• Immunology
• Pathology

Background:

• Functional dyspepsia (FD) can arise after acute gastroenteritis.
• Post-infectious (PI) irritable bowel syndrome is linked to colonic inflammation and increased enterochromaffin cells.
• Duodenal inflammation and immune cell changes in PI-FD are not well understood.

Purpose of the Study:

• To compare duodenal inflammation and enterochromaffin cell (EC) hyperplasia in PI-FD versus unspecified-onset (U-FD) patients.
• To investigate the association between duodenal findings and gastric emptying in PI-FD.

Main Methods:

• Duodenal biopsies analyzed for intra-epithelial and intravillar immune cells (CD3, CD4, CD8, CD68) and Chromogranin A (CA).
• Compared immune cell counts and EC numbers between 12 PI-FD and 12 U-FD patients.
• Assessed gastric emptying and proximal stomach function using a barostat.

Main Results:

• PI-FD patients exhibited focal T-cell aggregates (5/12) and CD8+ aggregates (5/9), absent in U-FD.
• Focal aggregates correlated with delayed gastric emptying (189 min vs 98 min).
• PI-FD showed reduced duodenal CD4+ cells and increased CD68+ (macrophage) cells per crypt, with comparable EC and CA counts.

Conclusions:

• PI-FD is characterized by persistent focal duodenal T-cell aggregates and altered immune cell profiles.
• These findings suggest an impaired immune response resolution following acute infection in PI-FD.
• Duodenal immune changes may contribute to the pathophysiology of PI-FD.