Complement proteins changes in ischemic stroke patients and their relation to outcome

We studied plasma levels of complement system factors C1q, C2, C3, C3b, C4, C4b, C5, C5a, C9 of 84 patients with ischemic stroke within 24 h from onset of symptoms and on seventh day after admission, using Luminex immunoassay. C1q, C2, C3, C3b, C4, C4b, C5, C5a levels were significantly lower at Day 7, compared to Day 1. Patients with poor outcome (NIHSS ≥16 or death) had significantly higher C9 levels at both time points, and higher C2, C5 and C5a levels on Day 7 than the rest of the group. C2, C5, C5a and C9 correlated with final NIHSS score at both time points. Conclusions: Plasma levels of complement change dynamically within first days of the acute phase of ischemic stroke. Higher baseline C9 is associated with worse outcome in acute phase of ischemic stroke.