title: Phospholipid-dependent procoagulant activity is highly expressed by circulating microparticles in patients with essential thrombocythemia.
abstract: This study evaluates the functional procoagulant features of plasma microparticle (MP) to explore the MP contribution to the hypercoagulable state of patients with essential thrombocythemia (ET). Platelet-free plasma samples were obtained from 73 ET patients (37 positive for the JAK2V617F mutation) and 72 control subjects. The calibrated automated thrombogram (CAT) was performed in plasma samples to determine thrombin generation of MP-associated tissue factor (TF) and procoagulant phospholipid (PPL) activity, and the STA Procoag PPL assay to measure MP-PPL activity only. Both thrombin generation and PPL procoagulant activities were found significantly elevated in ET patients compared to controls, and were associated to significantly higher levels of TF antigen and FVIIa/AT complex. Thrombin generation was significantly greater in JAK2-V617F positive compared to JAK2-V617F negative patients and normal subjects. Significant correlations were found between the PPL-assay and the different parameters of the CAT assay. No difference was seen between the thrombosis and no thrombosis group. Prospective studies are needed to test whether MP-associated thrombin generation and procoagulant activity may predict for thrombosis in these patients.
authors.affiliation: Division of Immunohematology and Transfusion Medicine, Hospital Papa Giovanni XXIII, Bergamo, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Marchetti
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Tartari
authors.forename: Laura
authors.initials: L
authors.lastname: Russo
authors.forename: Marina
authors.initials: M
authors.lastname: Panova-Noeva
authors.forename: Annamaria
authors.initials: A
authors.lastname: Leuzzi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rambaldi
authors.forename: Guido
authors.initials: G
authors.lastname: Finazzi
authors.forename: Barry
authors.initials: B
authors.lastname: Woodhams
authors.forename: Anna
authors.initials: A
authors.lastname: Falanga
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001777:Blood Coagulation; D016022:Case-Control Studies; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D015942:Factor VIIa / Q000378:metabolism; D005260:Female; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010743:Phospholipids / Q000378:metabolism*; D013917:Thrombin / Q000096:biosynthesis; D013920:Thrombocythemia, Essential / Q000097:blood / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D013925:Thromboplastin / Q000378:metabolism; D055815:Young Adult
chemical_list: D010743:Phospholipids; D013925:Thromboplastin; D053614:Janus Kinase 2; D015942:Factor VIIa; D013917:Thrombin