Tumor necrosis factor alpha serum levels and inflammatory response in acute ischemic stroke

OBJECTIVE: To assess the implication of tumor necrosis factor alpha (TNF-alpha) and interleukine-6 (IL-6) in acute ischemic stroke and to correlate this with lesion size, vascular risk factors, and neurological impairment.

METHODS: We included 70 patients consecutively admitted to the Department of 1st Neurology, Haydarpasa Numune Educational and Research Hospital, Istanbul, Turkey, between September 2001 and April 2002, with first-ever ischemic cerebral infarction within the first 24 hours from onset. The TNF-alpha, IL-6, fibrinogen, C-reactive protein, erythrocyte sedimentation rate (ESR) and leukocytes were determined in plasma on admission. Neurological impairment was evaluated with the modified Rankin Scale.

RESULTS: We found higher baseline levels of TNF-alpha and IL-6 in the plasma of patients with acute ischemic stroke and neurological impairment in comparison to control subjects. In the large infarct group, TNF-alpha, IL-6, low-density lipoprotein-cholesterol and fibrinogen were found significantly higher compared to the small infarct group. While an association between TNF-alpha and IL-6 values and lesion size were determined, no relation was found between localization and etiology. The TNF-alpha level was found to be in positive correlation with IL-6, fibrinogen, and ESR. The IL-6 level was found to be in positive correlation with ESR fibrinogen, and leukocytes.

CONCLUSION: Inflammatory findings are associated with the early stage of ischemic stroke. The TNF-alpha and IL-6 were also higher in patients with clinical worsening. The release of proinflammatory cytokines after focal cerebral ischemia indicates a step leading to tissue necrosis or reflects the amount of ischemic brain injury, since the higher concentrations of TNF-alpha and IL-6 are found in patients with large infarctions.