Conclusions:
The gastrointestinal tissue of patients with IN-COL is characterised by
high levels of activated memory CD8+ T cells and MAIT
cells. These changes were distinct from the peripheral blood compartment
where CD8+ T cell activation reflected an on-treatment
effect, and where circulating MAIT cell count was significantly lower
than in health but neither could predict the onset of colitis. Further
work is required to determine the pathway by which
CD8+ T cells and MAIT cells become activated in the
gut of patients with ICI-associated colitis and whether MAIT cells
contribute to tissue damage or repair. Advancements in this area have
the potential to inform novel treatment strategies for this new and
distinct inflammatory bowel disease.