PLATELET FUNCTION (PFA-100) AND ACTIVATION IN PATIENTS WITH CHRONIC PHILADELPHIA NEGATIVE MYELOPROLIFERATIVE DISORDERS: ROLE OF THE JAK2 V617F MUTATION
Abstract number: P-M-322
Moreno1 M.J., Martínez1 C., Navarro-Núñez1 L., Ferrer1 F., Vicente1 V., Lozano1 M.L., González1 M.H., Rivera1 J.
1Centro Regional de Hemodonación, University of Murcia, Murcia, Spain
How-to-cite Moreno MJ, Martínez C, Navarro-Núñez L, Ferrer F, Vicente V, Lozano ML, González MH, Rivera J. PLATELET FUNCTION (PFA-100) AND ACTIVATION IN PATIENTS WITH CHRONIC PHILADELPHIA NEGATIVE MYELOPROLIFERATIVE DISORDERS: ROLE OF THE JAK2 V617F MUTATION. J Thromb Haemost 2007; 5 Supplement 2: P-M-322
Introduction: The mechanisms of thrombotic complications in patients with chronic Philadelphia negative myeloproliferative disorders (MPDs) remain poorly understood. This study aimed to evaluate the role of JAK2 V617F mutation on platelet function and in the occurrence of major thrombotic events.
Methods: PFA-100 tests, using Col-EPI and Col-ADP cartridges, were done in citrated blood from 27 controls and 92 patients with MPDs [7 idiopathic myelofibrosis (IM), 26 polycythemia vera (PV), and 59 essential thrombocythemia (ET)][45M, 48F, median age 66 yrs). Fifty patients (54%) were under aspirin. The V617F mutation was identified on granulocyte DNA by allele specific PCR. Platelet activation (CD62) was evaluated by flow cytometry. Haematologic parameters were also measured and major thrombotic complications at diagnosis were recorded.
Results: As compared with controls, patients non-treated with aspirin (n=42) displayed closure times (CT, s) slightly longer for Col-ADP (11461 vs. 9213) and significantly prolonged for Col-EPI (17366 vs. 13659) (p<0.05). As expected, aspirin-treated patients showed significantly longer CT for Col-EPI (25467). In the patient group, CT correlated with platelet count, but not with haematocrit or vWF level. The V617F mutation was identified in 58 patients [3 IM(43%), 23 PV(88%), 32 ET(53%)]. In the absence of aspirin, 617F carriers (n=26) showed shorter, but non significantly different, CT for Col-EPI (16664 vs. 18368) and also a slightly higher CD62 (%) expression (5.97.0 vs. 3.92.3, and 4.73.5 in controls). A higher incidence of thrombosis was observed in F617 carriers (29.3 vs. 11.7%) (OR 3.11, p=0.05).
Conclusions: Patients with MPDs show a mildly affected platelet function in the PFA-100 system. The V617F mutation seems to increase the thrombotic risk and may associate to slightly increased platelet reactivity.
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Journal of Thrombosis and Haemostasis 2007; Volume 5, Supplement 2: abstract number
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