The role of the innate and adaptive immune system in pediatric inflammatory bowel disease

Area of Science:

• Pediatric Gastroenterology
• Immunology
• Genetics

Background:

• Translational studies offer new insights into pediatric-onset inflammatory bowel disease (IBD) pathogenesis.
• Distinct clinical phenotypes are identified with increasing age of onset, leading to the Paris classification system.
• IBD is categorized into infantile (<1 year), very early onset (VEO) (1-10 years), and early onset (10-17 years) forms.

Purpose of the Study:

• To review recent advances in understanding the pathogenesis of pediatric-onset IBD.
• To highlight the revised phenotyping system (Paris classification) and its implications.
• To discuss the roles of genetics, environmental factors, and gut dysbiosis in pediatric IBD.

Main Methods:

• Review of translational studies and registry data.
• Analysis of genetic mutations in infantile and VEO IBD.
• Examination of environmental influences and their impact on enteric flora and immune responses.

Main Results:

• Identification of distinct IBD phenotypes based on age of onset (infantile, VEO, early onset).
• Discovery of rare genetic mutations in infantile and VEO IBD, distinct from adult-onset IBD pathways.
• Increasing incidence in infantile and VEO forms suggests significant environmental influence, leading to dysbiosis and immune dysregulation.

Conclusions:

• Pediatric IBD pathogenesis is complex, involving genetic predisposition and environmental triggers.
• Gut dysbiosis and immune dysregulation are critical in initiating mucosal inflammation.
• Understanding these factors is essential for developing new pathogenic models, guiding therapy, and informing disease prevention strategies for at-risk families.