In order to validate the existence and localization of fibrocytes, co-immunofluorescence staining was performed and the results showed that numerous CD45+COL1+ fibrocytes were significantly increased in both mouse (Figures 5A,B) and human (Figures 5C,D) AAA tissues, suggestive of fibrocytes mainly in the adventitia. This evidence concerns the gene PTPRC and triple-A syndrome.