['The etiology of abdominal aortic aneurysm (AAA) includes atherosclerotic, inflammatory, immunological and coagulatory mechanisms. The aim of this study was to evaluate associations between markers for some of these mechanisms and AAA-size, in order to identify markers which might later be evaluated in relation to aneurysm growth.', 'Prospectively 360 AAA-patients and an age and sex-matched healthy control group (n=219) were analyzed. AAA-patients were divided in three groups according to AAA-diameter (small <45 mm, n=122, medium 45-55 mm, n=108, and large >55 mm, n=130). Associated diseases, blood pressures and routine laboratory markers were analyzed. Additionally we evaluated endothelin (ET)-1, tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, activated protein C-protein C inhibitor (APC-PCI) complex, and CD40 ligand. Groups were compared with the Kruskall-Wallis test and the Mann-Whitney U test.', 'Of routine markers platelet count was lower (p=0.0006) and creatinine level was higher (p=0.028) in patients with large AAA. Almost all non-routine markers analyzed were highly elevated in AAA-patients compared to the control group. IL-6 (p=0.0002) and thrombin activation measured as APC-PCI (p<0.0001) increased depending on the size of AAA.'] Are cytokines and systemic biomarkers related to the size of abdominal aortic aneurysms?