Increase of Vδ2⁺ T Cells That Robustly Produce IL-17A in Advanced Abdominal Aortic Aneurysm Tissues

Abdominal aortic aneurysm (AAA) is a chronic dilation of the aorta with a tendency to enlarge and eventually rupture, which constitutes a major cause of cardiovascular mortality. Although T-cell infiltrates have been observed in AAA, the cellular, phenotypic, and functional characteristics of these tissue-infiltrating T cells are not fully understood. Here, we investigated the proportional changes of T-cell subsets-including CD4⁺ T cells, CD8⁺ T cells, and γδ T cells-and their effector functions in AAAs. We found that Vδ2⁺ T cells were presented at a higher frequency in aortic aneurysmal tissue compared to normal aortic tissue and PBMCs from patients with AAA. In contrast, no differences were observed in the frequencies of CD4⁺, CD8⁺, and Vδ1⁺ T cells. Moreover, we observed that the Vδ2⁺ T cells from AAA tissue displayed immunophenotypes indicative of CCR5⁺ non-exhausted effector memory cells, with a decreased proportion of CD16⁺ cells. Finally, we found that these Vδ2⁺ T cells were the main source of IL-17A in abdominal aortic aneurysmal tissue. In conclusion, our results suggest that increased Vδ2⁺ T cells that robustly produce IL-17A in aortic aneurysmal tissue may contribute to AAA pathogenesis and progression.