Surface protein and functional analyses identify CD4⁺CD39⁺ TCR ⁺ and activated TCR V1⁺ cells with distinct pro-inflammatory functions in Crohn's disease lesions

Crohn's disease (CD) is a chronic immune-mediated disorder of the gastrointestinal tract. Extensive screening studies have revealed the accumulation of immune cell subsets with unique plasticity and immunoregulatory properties in patients with CD. We performed phenotypic and functional studies on inflamed and non-inflamed bioptic tissue to investigate the presence of distinct T cells in the intestinal mucosa of CD patients. We analysed hundreds of surface molecules expressed on cells isolated from the intestinal tissue of CD patients using anti-CD45 mAbs-based barcoding. A gene ontology enrichment analysis showed that proteins that regulate the activation of T cells were the most enriched group. We, therefore, designed T-cell focused multicolour flow-cytometry panels and performed clustering analysis which revealed an accumulation of activated T-EM CD4(+)CD39(+) T cells producing IL-17 and IL-21 and increased frequency of terminally differentiated TCR V delta 1(+) cells producing TNF-alpha and IFN-gamma in inflamed tissue of CD patients. The different functional capacities of CD4(+) and TCR V delta 1(+) cells in CD lesions indicate their non-overlapping contribution to inflammation. The abnormally high number of terminally differentiated TCR V delta 1(+) cells suggests that they are continuously activated in inflamed tissue, making them a potential target for novel therapies.