•PTPN22, the gene encoding for protein tyrosine phosphatase non-receptor type 22, was identified as a potential AAA biomarker during cross-comparisons of GO public datasets. Analysis of the GSE166676 scRNA-seq database demonstrated upregulation of PTPN22 within AAA tissues. Re-clustering using lineage-specific biomarkers identified the cells expressing higher PTPN22 as immune cell origin. Subpopulation analysis defined these cells as T cells, NK cells, and B cells•Analysis of VSMCs via ACTA2 expression showed AAA VSMCs to have higher expression of PTPN22. This evidence concerns the gene PTPN22 and triple-A syndrome.