A2M and abdominal aortic aneurysm: Similarly matched trends for abundance in both circulating plasma and tissue proteome of DTAA relative to Type B patients was observed for another heme scavenger, A2M, as well as proteins IGHV6-1, HRG, PGLYRP2 and F13A and B. Prominent involvement of immunoglobulins including IGHV6-1 is consistent with recent reports of a potentially pathogenic role for B cells and immunoglobulin deposition in abdominal aortic aneurysm (AAA) [37], and suggests similar involvement in the descending thoracic aorta.