Table 1.
Activation endpoints of procoagulant platelets and common flow cytometry markers to detect and discriminate them.
| Endpoint | Description | Common Markers | Phenotype in Procoagulant Platelets | Phenotype in Non-Procoagulant Platelets |
|---|---|---|---|---|
| Necrotic-like | ||||
| Phosphatidylserine | Negatively charged amino-phospholipids of platelet membrane bilayer, contribute to the procoagulant activity | Annexin V, lactadherin |
Positive | Negative |
| Mitochondrial membrane depolarization | Mitochondrial events (depolarization) are implicated in platelet procoagulant activity process | Rhodamine (such as TMRM) |
Low TMRM staining | High TMRM staining |
| JC-1 | Lower JC-1 fluorescence ratio (red/green) | Higher JC-1 fluorescence ratio (red/green) | ||
| Fibrinogen receptor GPIIb/IIIa (integrin αIIbβ3) |
Platelet membrane glycoprotein; in its activated conformation binds to fibrinogen and mediates platelet aggregation | Anti-CD41/CD61 IgM antibody recognizing the activated conformation (PAC-1) | Negative | Positive |
| Platelet surface coating by α-granule proteins | Proteins present in α-granule secreted upon platelet activation and retained on the platelet surface by a serotonin- and transglutaminase mechanism | Specific antibodies against α-granule proteins, such as FV/Va, fibrinogen, VWF, fibronectin, thrombospondin, and α2-antiplasmin | Positive | Negative |
Legend: FV, coagulation factor V; FVa, activated coagulation factor V; TMRM, tetra-methyl-rhodamine methyl ester; VWF, von Willebrand factor.