Immune Adaptations in Chronic Inflammation Promote Dysplasia in Colitis-Associated Cancer Risk

Overview

This study reveals that chronic inflammation in IBD patients induces immune adaptations characterized by increased anti-inflammatory cytokine production and decreased CD8+ intraepithelial T cells, which may undermine immunosurveillance and promote dysplasia. These findings were validated across multiple patient cohorts, highlighting persistent epithelial stress responses and immune reprogramming in histologically uninflamed mucosa.

Background

Colitis-associated cancer (CAC) is a severe complication of inflammatory bowel disease (IBD), with risk increasing alongside chronic inflammation duration and severity. Despite remission, IBD patients remain at elevated CAC risk, suggesting persistent pro-tumorigenic mucosal changes. While prior research focused on pro-inflammatory drivers of dysplasia, the role of endogenous anti-inflammatory mechanisms and immunosuppression in CAC onset remains underexplored. Understanding these immune adaptations in non-dysplastic, uninflamed mucosa is critical for early risk stratification and prevention.

Data Highlights

Key Findings

• Histologically uninflamed colon tissue from CAC patients showed upregulated metabolism and stress response pathways compared to sporadic colorectal cancer (SCRC) patients, indicating ongoing epithelial stress.
• Endogenous anti-inflammatory mechanisms were evident, including increased IL-10 expression by lamina propria IgA+ plasma cells and CD163+ macrophages in CAC patients.
• T cell recruitment and effector functions were downregulated in CAC, with a notable decrease in CD8+ intraepithelial lymphocytes (IELs) and reduced granzyme B levels within these cells.
• Lower CD8+ IEL density correlated with CAC susceptibility; IBD patients who developed dysplasia had significantly fewer CD8+ IELs than those who did not.
• Chronic inflammation induces immune adaptations that protect tissue from damage but may simultaneously impair immunosurveillance, facilitating dysplasia development.

Clinical Implications

These findings suggest that monitoring CD8+ intraepithelial lymphocyte density and IL-10 expression in histologically normal mucosa could aid in identifying IBD patients at higher risk for CAC. Therapeutic strategies balancing anti-inflammatory protection and preservation of immunosurveillance may improve prevention of dysplasia and cancer in this population.

Conclusion

Chronic inflammation in IBD triggers immune adaptations that reduce immunosurveillance by decreasing CD8+ IELs and increasing anti-inflammatory cytokines, thereby promoting dysplasia and CAC risk. Understanding these mechanisms offers new avenues for early detection and intervention.

References

1. Original Article 2024 -- Spatial Transcriptomics and Immune Profiling Reveal Immune Adaptations Induced by Chronic Inflammation That Promote Dysplasia in Colitis-Associated Cancer Risk Patients