Myeloproliferative neoplasms (MPNs) are uncommon in children/young adults. Here, we present data on unselected patients diagnosed before 25 years of age included from 38 centers in 15 countries. Sequential patients were included. We identified 444 patients, with median follow-up 9.7 years (0-47.8). Forty-nine (11.1%) had a history of thrombosis at diagnosis, 49 new thrombotic events were recorded (1.16% patient per year [pt/y]), perihepatic vein thromboses were most frequent (47.6% venous events), and logistic regression identified JAK2V617F mutation (P = .016) and hyperviscosity symptoms (visual disturbances, dizziness, vertigo, headache) as risk factors (P = .040). New hemorrhagic events occurred in 44 patients (9.9%, 1.04% pt/y). Disease transformation occurred in 48 patients (10.9%, 1.13% pt/y), usually to myelofibrosis (7.5%) with splenomegaly as a novel risk factor for transformation in essential thrombocythemia (ET) (P= .000) in logistical regression. Eight deaths (1.8%) were recorded, 3 after allogeneic stem cell transplantation. Concerning conventional risk scores: International Prognostic Score for Essential Thrombocythemia-Thrombosis and new International Prognostic Score for Essential Thrombocythemia-Thrombosis differentiated ET patients in terms of thrombotic risk. Both scores identified high-risk patients with the same median thrombosis-free survival of 28.5 years. No contemporary scores were able to predict survival for young ET or polycythemia vera patients. Our data represents the largest real-world study of MPN patients age < 25 years at diagnosis. Rates of thrombotic events and transformation were higher than expected compared with the previous literature. Our study provides new and reliable information as a basis for prospective studies, trials, and development of harmonized international guidelines for the specific management of young patients with MPN.

• MeSH
• dítě MeSH
• dospělí MeSH
• esenciální trombocytemie * MeSH
• lidé MeSH
• mladý dospělý MeSH
• myeloproliferativní poruchy * komplikace   diagnóza   epidemiologie   MeSH
• polycythaemia vera * komplikace   MeSH
• primární myelofibróza * genetika   MeSH
• prospektivní studie MeSH
• trombóza * etiologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND/AIM: This work aimed to prospectively evaluate the clinical significance of circulating microparticles (MPs) in relation to thrombotic risk factors and thrombotic complications in patients with BCR/ABL1-negative myeloproliferative neoplasms (MPN). PATIENTS AND METHODS: In a cohort of 206 patients with MPN, MPs' procoagulant activity was measured by the Zymuphen functional assay in 429 samples, while platelet- and erythrocyte-MPs were enumerated by flow cytometry in 558 samples. RESULTS: MPN patients had higher MP levels than the control group. The levels of MPs were higher in male patients, smokers, and those who were older than 60 years, and in the presence of JAK2V617F mutation, history of thrombosis, platelets >400×109/l, hematocrit >45%, or leukocytes >10×109/l. Cytoreductive treatment reduced MP levels, with anagrelide being associated with lower MP levels than hydroxyurea. CONCLUSION: The relationship with thrombotic risk factors indicates a possible role of MPs in the complex thrombotic mechanism, though cytoreductive treatment seems to affect this role through reducing MP levels.

• Klíčová slova
• Myeloproliferative neoplasm, anagrelide, hydroxyurea, microparticle, procoagulant activity, thrombosis,
• MeSH
• lidé MeSH
• mikropartikule * MeSH
• myeloproliferativní poruchy * farmakoterapie   genetika   MeSH
• nádory * MeSH
• trombocyty MeSH
• trombóza * etiologie   genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Arterial thrombosis is a common complication in patients with Ph- myeloproliferative neoplasms (MPN). We searched for the risk factors of stroke in MPN patients from anagrelide registry. We analyzed the potential risk factors triggering a stroke/TIA event in 249 MPN patients with previous stroke (n = 168) or Transient Ischemic Attack (TIA) (n = 140), and in 1,193 MPN control subjects (without clinical history of thrombosis). These patients were registered in a prospective manner, providing a follow-up period after Anagrelide treatment. The median age of the patients in the experimental group was of 56 years of age (ranging from 34-76) and of 53 years of age (ranging from 26-74) in the control group (p < 0.001). Using a multivariate model, we determined the following as risk factors: JAK2V617F mutation (OR 2.106, 1.458-3.043, p = 0.006), age (OR 1.017/year, 1.005-1,029, p = 0.006), male gender (OR 1.419, 1.057-1.903, p = 0.020), MPN diagnosis (OR for PMF 0.649, 0.446-0.944, p = 0.024), BMI (OR 0.687 for BMI > 25, 0.473-0.999, p = 0.05) and high TAG levels (OR 1.734, 1.162-2.586, p = 0.008), all of which were statistically significant for CMP development. Concerning the risk factors for thrombophilia, only the antiphospholipid syndrome (OR 1.994, 1.017-3.91, p = 0.048) was noteworthy in a stroke-relevant context. There was no significant difference between the blood count of the patients prior to a stroke event and the control group, both of which were under a cytoreductive treatment. We found that age, male gender, JAK2V617F mutation, previous venous thrombosis, and hypertriglyceridemia represent independent risk factors for the occurrence of a stroke in Ph- MPN patients.

• Klíčová slova
• JAK2, Myeloproliferation, Risk factor, Stroke, TIA, Thrombosis,
• MeSH
• cévní mozková příhoda etiologie   MeSH
• chinazoliny terapeutické užití   MeSH
• dospělí MeSH
• fibrinolytika terapeutické užití   MeSH
• Janus kinasa 2 genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• myeloproliferativní poruchy komplikace   genetika   MeSH
• rizikové faktory MeSH
• senioři MeSH
• trombóza etiologie   prevence a kontrola   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anagrelide MeSH Prohlížeč
• chinazoliny MeSH
• fibrinolytika MeSH
• JAK2 protein, human MeSH Prohlížeč
• Janus kinasa 2 MeSH