Unexpected low expression of platelet fibrinogen receptor in patients with chronic myeloproliferative neoplasms: how does it change with aspirin?

This study was conducted to evaluate the expression of fibrinogen receptors on platelets of Philadelphia-negative chronic myeloproliferative neoplasm (MPN) patients. We collected blood samples from 40 consecutive MPN patients and healthy volunteers. We performed flow cytometry analysis of P-selectin expression and integrin beta-3, activation of glycoprotein (GP) IIb/IIIa and fibrinogen receptor exposure (PAC-1 binding). Surprisingly, we found a very low PAC-1 binding capacity in MPN patients; however, the expression of PAC-1 was almost completely recovered with aspirin intake. We hypothesize that the hypercoagulable states observed in MPN patients could depend on a primarily plasma-driven impairment of fibrin turnover and thrombin generation.