CD4 and triple-A syndrome: The CD4 + T lymphocytes have been found to be the predominant cell type in AAA [56], which is consist with the T cell associated signaling pathways and MHC class II mediated antigen processes in our GO and KEGG analysis, since CD4 + T lymphocytes recognize antigens presented by MHC II class molecules while CD8 + T lymphocytes recognize antigens presented by MHC I class molecules.