EARLY INTRATHECAL PRODUCTION OF INTERLEUKIN-6 PREDICTS THE SIZE OF BRAIN LESION IN STROKE

Background and Purpose We have previously demonstrated that stroke inf luences systemic immune responses. The aim of the present study was to investigate patterns of local inflammatory response as a consequence of acute stroke. Methods Thirty stroke patients were studied prospecti vely on days 0 to 3, 7 to 9, 21 to 26, and after day 90 with clinical evaluations, radiological assessments, and analysis of serum and cereb rospinal fluid cytokine levels. Results Significantly increased levels of interleukin-6 (IL-6) in cerebrospinal fluid (P < .001) were observ ed in virtually all patients studied compared with healthy control sub jects. This increase was observed during the whole observation period but was significantly more pronounced within the first days after stro ke onset, with a peak level on days 2 and 3. This initial increase was significantly correlated (r = .65, P = .002) with the volume of infar ct measured by MRI 2 to 3 months later. Serum levels of IL-6 in stroke patients were significantly lower than cerebrospinal fluid levels of IL-6 (P = .013) and did not display any significant correlation to the size of the brain lesion. Also, increase in intrathecal but not syste mic production of IL-1 beta was observed early during the stroke. Only minor increases of cerebrospinal fluid interferon-gamma levels were o bserved in two patients. Conclusions Our study demonstrates an intrath ecal production of IL-6 and IL-1 beta in patients with stroke, support ing the notion of localized inflammatory response to acute brain lesio n. In addition, the significant correlation between early intrathecal production of IL-6 and the subsequent size of the brain lesion can be used as a prognostic tool, predicting the size of the brain damage bef ore it is possible to accurately visualize it with radiological method s.