Unravelling CD4⁺ T cell diversity and tissue adaptation of Tregs in abdominal aortic aneurysms through single‐cell sequencing

Immune cell infiltration is a significant pathological process in abdominal aortic aneurysms (AAA). T cells, particularly CD4 + T cells, are essential immune cells responsible for substantial infiltration of the aorta. Regulatory T cells (Tregs) in AAA have been identified as tissue‐specific; however, the time, location, and mechanism of acquiring the tissue‐specific phenotype are still unknown. Using single‐cell RNA sequencing (scRNA‐seq) on CD4 + T cells from the AAA aorta and spleen, we discovered heterogeneity among CD4 + T cells and identified activated, proliferating and developed aorta Tregs. These Tregs originate in the peripheral tissues and acquire the tissue‐specific phenotype in the aorta. The identification of precursors for Tregs in AAA provides new insight into the pathogenesis of AAA.