CTLA4 and aneurysm: Treg FOXP3 possessed special gene expression properties resembling both Treg and naïve T-cell traits (Figure 5C) with expression of unique Treg hallmarks FOXP3, IL2RA, TIGIT, TNFRSF14, and CTLA4 and blood T-cell-related genes SELL, LEF1, and CCR7, suggesting it as a subset of blood Treg that might exist in aneurysm dissection (Figure 5C).