Complement activation alone does not cause platelet activation or aggregation.

Platelets were incubated in serum and the complement system activated using FH19-20. Hirudin was included in the assays to prevent thrombin-mediated activation. A: Flow cytometry analysis of exposure of the activation marker P-selectin showed no activation of platelets due to complement activation. Shown are representative histograms of an assay performed three times. B: Complement activation did not lead to platelet aggregation. Complete aggregation was set to 100% light transmission. Shown are average values of an assay performed three times.