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.