Temporal Dynamics of Complement Activation and Outcome in Patients with Acute Ischemic Stroke
Immune-mediated inflammatory responses exacerbate brain injury and affect the prognosis in acute ischemic stroke (AIS). We characterized longitudinal complement activation after AIS using serial plasma samples from 10 patients and 8 controls. Initial markers of classical (C1q), lectin (mannose-binding lectin [MBL]), and alternative (Factor Bb [CFBb]) pathways, as well as regulatory (Factor H [CFH]) and downstream markers (C3a, C5a and C5b-9) were measured by ELISA at 9 time points. Stroke patients showed broad complement activation with increased C1q, MBL, CFBb, C3a, C5a, and C5b-9, and reduced CFH. C1q, MBL, and CFBb peaked around day 17. MBL was higher in patients with poor outcome, CFBb was higher with good outcome, and C5b-9 in severe strokes. These findings reveal pathway-specific complement dynamics after AIS and support complement as a target for stage-specific therapy.