Changes in plasma levels of complement in patients with acute ischemic stroke.

Inflammatory processes are involved in cerebral ischemia. Patients with ischemic stroke may be predisposed to marked activation of the inflammatory system. The objective was to analyze the association between the level of complement at different stages after stroke and outcome. We collected blood samples from 179 patients (81 men and 98 women, mean age 73±5.6 years) within 24 hours after ischemic stroke, within 48 to 72 hours and at hospital discharge (16±7 days) as compared to 156 healthy controls, matching ischemic stroke patients with regard to sex and age. We measured levels of total hemolytic activity of serum complement (EIA method) and of C3, C4 (nephelometric measurements). The data were evaluated using χ 2 test. Within 24 hours after ischemic stroke in 38% patients mean value of CH50 was 148.4±57 CH50 U Eq/mL (p<0.05), of C3 was 1.49±0.24 mg/L (p<0.05) and of C4 was 0.32±0.08 mg/L (p<0.05). Within 48-72 hours after ischemic stroke in 34% patients mean value of CH50 was 167±5.9 CH50 U Eq/mL (p<0.01), of C3 was 1.58±0.27 mg/L (p<0.01) and of C4 was 0.38±0.08 mg/L (p<0.01). At hospital discharge in 31% patients mean value of CH50 was 192.8±64 CH50 U Eq/mL (p<0.001), of C3 was 1.66±0.28 mg/L (p<0.001) and of C4 was 0.49±0.07 mg/L (p<0.001). Patients with ischemic stroke who had elevated complement levels (inflammatory marker) at discharge had a worse neurological disability; complement might directly contribute to vascular damage.