Immunopathogenesis of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) arises from a complex interplay between genetic susceptibility, environmental triggers and the mucosal immune system. Central to its immunopathogenesis is disruption of the intestinal barrier, allowing luminal antigens and microbiota to engage both innate and adaptive immune pathways. Innate mechanisms, including epithelial cell integrity, antimicrobial peptides and pattern recognition receptors, set the stage for immune sensing. On this foundation, antigen-presenting cells such as dendritic cells orchestrate T-cell responses. A hallmark of IBD is the imbalance between proinflammatory T helper 17 (Th17) cells and immunoregulatory T cells (Tregs), driven by cytokine networks centred on interleukin-23, interleukin-17 and tumour necrosis factor. Dysregulated cytokine production perpetuates barrier damage, recruits neutrophils and monocytes, and sustains chronic inflammation. Genetic variants affecting mucosal barrier proteins, cytokine signalling molecules and microbial sensing receptors further amplify immune dysregulation. Metabolic factors, diet and the composition of the gut microbiota modulate T-cell differentiation pathways, reinforcing a cycle of epithelial injury and immune activation. Understanding these interconnected mechanisms has informed novel therapies aimed at restoring immune balance, reinforcing barrier function and reshaping microbial communities to achieve durable remission.

Research from Nature Portfolio

Recent studies have elucidated how extra-intestinal microbes influence gut inflammation via metabolic signalling. One investigation demonstrated that the oral pathogen Porphyromonas gingivalis worsens colitis by altering the gut microbiota and suppressing linoleic acid metabolism. Reduced linoleic acid diminishes aryl hydrocarbon receptor activation, skewing the Th17/Treg balance towards proinflammatory Th17 cells. Restoring linoleic acid levels in experimental colitis models rebalanced T-cell subsets and ameliorated inflammation, highlighting a modifiable metabolic axis for patients with concurrent periodontitis and IBD.

Immunopathogenesis of Inflammatory Bowel Disease publication trend

The graph below shows the total number of articles in immunopathogenesis of inflammatory bowel disease across all publications each year (not limited to Nature Index journals).

Technical terms

Immunopathogenesis: The process by which immune mechanisms contribute to disease development and progression.

Th17 cells: A subset of CD4+ T helper cells that produce interleukin-17 and promote mucosal inflammation.

Regulatory T cells (Tregs): A T-cell subset that suppresses immune responses to maintain tolerance and limit inflammation.

Cytokines: Soluble proteins released by immune cells that mediate signalling and coordinate inflammatory responses.

Necroptosis: A regulated form of cell death characterised by membrane rupture and release of inflammatory mediators.

Aryl hydrocarbon receptor (AHR): A ligand-activated transcription factor that links microbial metabolites to T-cell differentiation.

References

1. Type 17 immunity: novel insights into intestinal homeostasis and autoimmune pathogenesis driven by gut-primed T cells. Cellular & Molecular Immunology (2024).
2. Porphyromonas gingivalis aggravates colitis via a gut microbiota-linoleic acid metabolism-Th17/Treg cell balance axis. Nature Communications (2024).
3. Metabolic regulation of the Th17/Treg balance in inflammatory bowel disease. Pharmacological Research (2024).
4. High-Salt-Diet (HSD) aggravates the progression of Inflammatory Bowel Disease (IBD) via regulating epithelial necroptosis. Molecular Biomedicine (2023).