MKI67 and aortic aneurysm: Aortic conventional T cells (Tconvs, defined as CD4+Foxp3–cells) in aortic aneurysm also exhibited an increased amount of Ki67 expression compared with the spleen Tconvs, however the fractions of Ki67+ within aorta Tconvs was significantly lower than that of the aorta Tregs, indicating that Tregs in AAA exhibited a proliferative phenotype (Figure 3a).