Plasma level of IL-6 and its relationship to procoagulant and fibrinolytic markers in acute ischemic stroke

Procoagulant or impaired fibrinolytic states as well as inflammatory reactions mediated by cytokines are likely involved in the pathogenesis of acute ischemic stroke. We examined the potential relationship between interleukin 6 (IL-6) and hemostatic markers. The procoagulant and fibrinolytic states were assessed in 46 patients with acute stroke by measuring plasma levels of plasminogen activator inhibitor-1 (PAI-1), thrombin-antithrombin complex (TAT), and plasminogen-antiplasmin complex (PAP). Circulating IL-6 levels were measured using ELISA (Quantikine, R and D systems, MN, USA). Circulating IL-6 (mean, 26.5 pg/mL) and PAI-1 (mean, 19.9 ng/mL) levels were higher in patients with acute stroke than in healthy subjects (mean, 3.0 pg/mL, 10.4 ng/mL, respectively). TAT levels were statistically different according to the etiologic subtypes of stroke (atherogenic, 2.5 ng/mL; lacunar 3.2 ng/mL; cardiogenic 9.9 ng/mL, p = 0.021). Neither procoagulant levels nor fibrinolytic markers significantly correlated with circulating IL-6 levels. Our findings suggest that elevated proinflammatory cytokines during the initial hours of ischemic stroke may be an independent pathogenic factor or a consequence of the thrombotic event with no relationship to the procoagulant or fibrinolytic states.