Inflammation in the wall of abdominal aortic aneurysm and its role in the symptomatology of aneurysm.

Cytosol levels of cytokines [interleukins 1b, 6, 8 (IL-1b, 6, 8), tumor necrosis factor-alpha (TNF-alpha)] in aneurysm walls were evaluated in a prospective non-randomized study of 57 patients. The group was divided into two subgroups: Subgroup I (ruptured aneurysms, n=11) and Subgroup II (asymptomatic aneurysms, n=32). A control group consisted of 14 kidney donors. Aortic walls were examined by immunohistochemistry and microscopy to detect inflammatory cells. More pronounced inflammatory changes and higher cytosol cytokine levels [IL6 (p<0.001), IL8 (p<0.0003) and TNFalpha (p<0.002)] were found in the walls of ruptured aneurysms than in the asymptomatic aneurysms. Immunohistochemically, most cells within the inflammatory infiltrates stained positively with the monoclonal antibody to the leucocyte common antigen (CD 45). The majority were of B-cell origin, which was demonstrated by positive staining with the monoclonal antibody L26 directed against the CD 20 antigen. These results show that an inflammatory process plays a significant role in patients with ruptured abdominal aortic aneurysms (AAA). A means of modifying the inflammatory process in the wall of AAAs might play an important role in preventing aneurysm rupture.