OBJECTIVE: The role of inflammation in the pathogenesis of acute ischemic stroke 
is well known, but its association with the clinical picture is as yet unclear.
MATERIAL AND METHODS: In our study, we measured the serum levels of the 
proinflammatory cytokines interleukin-1beta (IL-1beta), tumor necrosis factor 
alpha (TNFalpha) and interleukin-6 (IL-6) within the first 50 h of stroke in 60 
acute stroke patients, and examined the association with the natural 
anticoagulants protein C and free protein S. We compared the results with a 
control group that consisted of 30 volunteers. We also correlated their levels 
with the clinical outcomes by using the Canadian Neurological Scale (CNS).
RESULTS: Neither stroke patients nor the control group had any elevations in 
IL-1beta serum levels. However, the levels of serum IL-6 were significantly 
higher in stroke patients (13.7 +/- 19.46 vs. 4.3 +/- 15.88, p = 0.002). In 
addition, the protein S levels of patients were lower than those of the controls 
(84.36 +/- 27.97 vs. 95.9 +/- 25.64, p = 0.007). Although IL-6 showed negative 
correlation with protein S (r = -0.504, p = 0.000), the other studied cytokines 
TNFalpha and IL-1beta did not correlate with these natural anticoagulants. 
Another negative correlation was found between IL-6 and CNS scores (r = -0.451, 
p = 0.000). In addition, both protein C and protein S positively correlated with 
CNS (r = 0.263, p = 0.042; r = 0.381, p = 0.003). There was also a positive 
correlation between protein C and protein S (r = 0.408, p = 0.001).
CONCLUSIONS: Our results suggest that TNFalpha and IL1beta serum levels are not 
elevated in the acute phase of stroke and have no correlation with the natural 
anticoagulants protein C and protein S. However, a decrease in free protein S 
may be related to elevated IL-6 levels. In addition, increased levels of IL-6 
and reduced levels of protein C and protein S may play a role in acute ischemic 
stroke severity.