Lapecorella Mario, Tabilio Antonio, Lucchesi Alessandro, Napolitano Mariasanta, Colagrande Marianna, Di Ianni Mauro, Mariani Guglielmo
Centro Emofilia e Trombosi- Unità Operativa Medicina Interna 2 - Ematologia, Università de L'Aquila - Ospedale San Salvatore, Coppito- L'Aquila, Italy.
Blood Coagul Fibrinolysis. 2008 Jul;19(5):453-7. doi: 10.1097/MBC.0b013e3283079e46.
The discovery of the Janus kinase 2 Val617Phe mutation has brought new insights into the development of myeloproliferative disorders; however, the pathogenesis of essential thrombocythemia and its related thrombotic complications has not been completely understood. Although the Janus kinase 2 Val617Phe mutation confirms the initially suspected clonal character of the disease, factors influencing clonal transformation and expansion in the bone marrow have not been fully detected. Furthermore, patients affected by essential thrombocythemia who are carriers of the Janus kinase 2 Val617Phe mutation show a higher incidence of venous thromboembolism both before, and at the time of diagnosis, compared with noncarriers, and recent evidence of splanchnic and cerebral vein thrombosis in carriers of the Janus kinase 2 Val617Phe mutation has been reported. The intake of oral contraceptives is a strong and independent risk factor for venous thromboembolism. In addition, in-vitro tests showed both an altered primary haemostatic plug formation and enhanced platelet aggregation in patients taking such drugs. Little is known, though, about the influence of steroid hormones on both megakaryopoiesis and platelet function in patients with the Janus kinase 2 Val617Phe mutation. Herewith, we report the case of a 30-year-old woman who took a third generation oral contraceptive for 5 months and developed an essential thrombocythemia with spleno-portal axis and superior mesenteric vein thrombosis. She was found to carry the kinase gene Janus kinase 2 mutation.
Janus激酶2（JAK2）Val617Phe突变的发现为骨髓增殖性疾病的发展带来了新的见解；然而，原发性血小板增多症及其相关血栓并发症的发病机制尚未完全明了。尽管JAK2 Val617Phe突变证实了该病最初所怀疑的克隆性特征，但影响骨髓中克隆转化和扩增的因素尚未完全查明。此外，与非携带者相比，携带JAK2 Val617Phe突变的原发性血小板增多症患者在诊断前及诊断时静脉血栓栓塞的发生率更高，并且已有报道称JAK2 Val617Phe突变携带者出现内脏和脑静脉血栓形成的最新证据。口服避孕药的摄入是静脉血栓栓塞的一个强烈且独立的危险因素。此外，体外试验显示服用此类药物的患者既有原发性止血栓形成改变，又有血小板聚集增强。然而，关于类固醇激素对JAK2 Val617Phe突变患者巨核细胞生成和血小板功能的影响却知之甚少。在此，我们报告一例30岁女性病例，该女性服用第三代口服避孕药5个月后发生原发性血小板增多症，并伴有脾门静脉轴和肠系膜上静脉血栓形成。她被发现携带激酶基因JAK2突变。
