Figure 3

Activation of platelets identified by the binding of the antibody PAC-1 to the activated conformer of GP IIb-IIIa. Patients with ESRD (n = 33) were stratified into 2 groups on the basis of median expression of FcγRIIa. Activation of platelets was quantified with the use of flow cytometry to define the percentage of platelets that bound PAC-1 in the absence of agonist and in response to the collagen mimetic convulxin (1 ng/ml), PAF (1 nM), ADP (0.2 μM), or thrombin (1 nM). Patients with high expression of FcγRIIa did not exhibit greater activation of platelets in the absence of agonist but did exhibit greater activation in response to each of the agonists used.