JAK2V617F mutation and circulating extracellular vesicles in essential thrombocythemia.

The clinical course of essential thrombocythemia (ET) is complicated with thrombosis which significantly impacts patients' mortality. Studies have identified JAK2V617F mutation as an independent risk factor for thrombosis. Circulating extracellular vesicles (EVs) were evaluated in several studies regarding myeloproliferative neoplasms and thrombosis as potential biomarkers. The present study investigates the relationship between JAK2V617F mutation and EVs levels in 119 ET patients. Our analyses revealed that JAK2V617F-positive patients are at a significantly increased risk of thrombosis within five years before the ET diagnosis (hazard ratio [95% CI]: 11.9 [1.7-83.7], P = 0.013), and that JAK2V617F mutation is an independent risk factor for thrombosis at ET diagnosis or during the follow-up (hazard ratio [95% CI]: 3.56 [1.47-8.62], P = 0.005). ET patients have higher levels of platelet-EVs, erythrocyte-EVs and procoagulant activity of EVs than the healthy population. Absolute and relative counts of platelet-EVs are increased in the presence of JAK2V617F mutation (P = 0.018, P = 0.024, respectively). In conclusion, our results support the role of JAK2V617F mutation in the pathogenesis of thrombosis in essential thrombocythemia through enhancing platelet activation.

Risk factors of thrombosis in a cohort of 206 patients with BCR-ABL1 negative myeloproliferative neoplasms.

Thrombosis is the most common complication in BCR-ABL1 negative myeloproliferative neoplasms (MPN) that significantly impacts patients' mortality. Generally, there is an agreement on risk factors that possibly contribute to the increased risk of thrombosis, including age, history of thrombosis, JAK2V617F mutation, and cardiovascular risk factors. This study retrospectively investigates MPN-related and patient-related variables in relation to the thrombosis occurrence in MPN. Our analyses show that JAK2V617F-mutated patients are at a significantly increased risk of thrombosis within five years before the MPN diagnosis point with a hazard ratio (HR) of 15.49 (p=0.006). In multivariate analyses, independent risk factors for thrombotic complications during the follow-up are history of thrombosis (HR=2.23, p=0.019), age over 60 years at diagnosis (HR=1.56, p=0.037), the presence of JAK2V617F mutation (HR=3.01, p=0.002), and tobacco smoking (HR=1.75, p=0.01). Our results support the multifactorial mechanism of thrombosis in MPN patients, which demands individual and complex management.

The Clinical Significance of Circulating Microparticles Concerning Thrombosis in BCR/ABL1-negative Myeloproliferative Neoplasms.

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.

Interferon-alpha in the treatment of myeloproliferative diseases.

Despite significant progress, the treatment options for myeloproliferative neoplasms (MPN) are still limited. Interferon α (IFNα) has been recognized as a substance for the treatment of MPN for more than 30 years, but its widespread use has been limited by higher frequency of short-term adverse reactions compared to conventional treatment and until recently, by its off-label indication in BCR/ABL negative MPNs. With the development of pegylated forms of IFNα with a more favorable toxicity and pharmacokinetic profile have renewed interest in the use of IFNα in the treatment of MPN. Recent studies confirm that IFNα is important drug capable of reducing the tumor population in MPN. Thus, IFNα is currently a more frequently considered drug in the treatment of MPN and has adop-ted into of some expert recom-mendations as a first-line drug for younger patients with various subtypes of MPN.

Thrombosis in thrombocythemic Ph- myeloproliferations is associated with higher platelet count prior to the event: results of analyses of prothrombotic risk factors from a registry of patients treated with anagrelide.

Controversies still exist regarding definition of the thrombotic risks in Ph- (BCR/ABL1-) myeloproliferative disorders with thrombocythemia (MPD-T). Platelet counts at diagnosis are currently not taken as a risk factor of thrombosis. In our cohort of 1179 patients with MPD-T, prospectively registered for anagrelide treatment, we found that the median platelet count prior to the thrombotic event was significantly higher than at time points without any ensuing thrombosis (453 vs. 400 × 10(9)/L, P < 0.001), albeit higher platelet counts at diagnosis tended to be connected with fewer thrombotic events (in contrast to WBC counts at diagnosis). The JAK2(V617F) mutation predicted both arterial and venous events, while age >65 yr, hypertension, diabetes mellitus, smoking, elevated triglyceride and homocysteine levels predicted arterial events only. For venous events, the specific thrombophilic risk factors (factor V 'Leiden' and others), antiphospholipid antibodies, and elevated factor VIII levels played a major role. During anagrelide treatment (± aspirin), we documented a decrease in both venous (6.7-fold) and arterial events (1.8-fold), while bleeding (mostly minor events) increased twofold compared to history. Our results suggest that keeping platelet counts at low levels may be a meaningful therapeutic measure to prevent thrombosis, although their counts at diagnosis lack any prognostic value.

[Myopathy in patients with Waldenströms macroglobulinemia. A case study and an overview of autoimmune expressions of type IgM monoclonal immunoglobulins]. / Myopatie pri Waldenströmove makroglobulinemii. Popis prípadu a prehled autoimunitních projevu monoklonálních imunoglobulinu typu IgM.

Waldenströms macroglobulinemia which was manifested by muscle pain and anemia. The female patient had suffered from back pain for about 3 years before she came to our clinic. In the last year pain in the muscles of the upper and lower extremities developed in addition to back pain. This led to the suspicion of polymyositis. However this was not confirmed by a special examination. The patient was diagnosed with clearly established infiltration of lympho-plasmacytic lymphoma and 10.8 g/l of type IgM monoclonal immunoglobulin in the bone marrow. Serum myoglobin levels and serum CK activity were repeatedly significantly increased. Therefore the treatment with anti-CD20 monoclonal antibody (Mabthera) 375 mg/m2 i. v. was started, administered once a month, with cyclophosphamide 500 mg/m2 i. v. on days 1 and 15 of a 28-day cycle, and dexamethasone 20 mg from 1st through to 4th days and 15th through to 18th days of the treatment cycle. There were 8 cycles planned. Already after a 5th cycle, the disappearance of monoclonal immunoglobulin (negative immunofixation), normalisation of myoglobin and CK values and significant relief from muscle pain were achieved. The hemoglobin concentrations before treatment were significantly reduced, while they were normalised after treatment. After 5 cycles, the complete remission of Waldenströms disease was reached according to biochemical parameters, and normalisation of the serum myoglobin and creatine kinase levels was achieved.

Increasing procoagulant activity of circulating microparticles in patients with Philadelphia-negative myeloproliferative neoplasms: a single-centre experience.

Microparticles are small membrane fragments with dimension between 0.1 and 1 µm, which are released during cell activation or apoptosis, exposing the phospholipid phosphatidylserine and membrane antigens typical for cellular origin. Philadelphia-negative myeloproliferative neoplasms (MPNs) are characterized by an increased risk of thrombosis. Data from literature suggest an association between thrombosis and the procoagulant activity of microparticles. Association between the procoagulant activity of microparticles and the incidence of thrombosis was assesed in a group of 126 patients with Philadelphia-negative MPNs. Measurement of microparticles procoagulant activity was performed using a functional assay, namely the Zymuphen MP-activity (Hyphen Biomed, Neuville-sur-oise, France). A total of 539 samples were analysed within this group of patients, regardless of patients' state of health. A significantly higher circulating microparticles procoagulant activity was found in MPN patients as compared with the control group (P < 0.001). A pathological level of procoagulant activity was observed more frequently in patients with polycythaemia vera (88%, P = 0.002) than groups of patients with essential thrombocythaemia (73.2%) and primary myelofibrosis (68.3%); the same result was confirmed in patients with a history of venous thrombosis in comparison with patients without thrombosis (84.7 vs. 73.2%, P = 0.029). Patients without cytoreductive treatment had a higher activity of microparticles (P = 0.010). Furthermore, presence of JAK2 V617F mutation was associated with an increased procoagulant activity (P = 0.007), as well as the higher JAK2 V617F allele burden (P = 0.001). Further prospective clinical studies will be necessary to evaluate the clinical relevance of microparticles in the prediction hypercoagulable state in these patients.

[Differential diagnostics of hypereosinophilia]. / Diferenciální diagnostika eozinofilie.

Hypereosinophilia is characterized by chronic increase of peripheral blood eosinophiles with common damage to vari-ous organs due to eosinophilic infiltration and release of mediators. Hypereosinophilia should be both reactive and clonal, and accompanies group of heterogeneous disorders (infectious, pulmonary, immunologic, malignant). Based on recent advances in molecular and genetic diagnostic techniques and increasing experience with differences in clinical features and prognosis, some subtypes of clonal hypereosinophilic syndromes have been defined, such as myeloproliferative variants, including chronic eosinophilic leukemia, and lymphocytic variants, but other subtypes remain undefined. Differential diagnostics oh hypereosinophilie therefore remains one of very important medical issues.Key words: differential diagnostics - hypereosinophilia.

[Ph-negative myeloproliferative diseases with thrombocythemia in the context of Thromboreductin® treatment, data from registry 2013]. / Ph-negativní myeloproliferativní onemocnení s trombocytemií ve svetle úcinku lécby prípravkem Thromboreductin® v datech registru ke konci roku 2013.

Czech Working Group for Ph-negative Myeloproliferative diseases (CZEMP) recommends anagrelid (Thromboreductin®) for the treatment of Ph-negative chronic myeloproliferative disease (MPO) with thrombocythemia accompanying. To evaluate the efficacy of this treatment, the patient registry with essential thrombocythemia and/or thrombocytosis accompanying other Ph-negative myeloproliferative diseases was established. The beginnings of data collection go back to 2001, registry itself is maintained from 2005 and the aim is to archive the medical records with detailed physical and laboratory examination, safety patient profile included. The longest follow-up monitors 150 months period. Registry database contained 1,325 patients in the end of 2013, with an annual increase of anagrelid therapy as a drug of first choice in accordance with CZEMP guidelines approved by the Czech Society of Hematology of Czech Medical Association of J. E. Purkyne. Indication criteria contribute to this trend as anagrelid is the first choice agent in 65 years old patients, instead previous 60 years of age. Often, we can observe the combined treatment, especially, in older patients and in patients with primary myelofibrosis and polycythemia vera. There have been founded 543 thrombotic events in 413 patients and 63 bleeding events in 58 patients of study group by the end of 2013. During treatment, thrombosis was diagnosed 225 times in 171 patients and bleeding was observed 139 times in 104 patients. The therapeutic response is achieved after 3 months in 77% and after 6 months in 83% of subjects, but after 12 months, the treatment still fails in 12,5% of patients. It might be caused by slow titration of Thromboreductin®. One of the most important indicators of treatment success is the effect on clinical symptoms presentation, especially the occurrence of thrombotic events. The proof of a good treatment efficacy is demonstrated by 1.8 fold decrease in arterial thrombosis, more than 1.5 fold decrease in microvascular thrombosis and even 6.2 fold decrease in venous thromboembolism events. Bleeding is observed in about double more patients in comparison to the period before inclusion in the systematic monitoring, but the bleedings are clinically insignificant.Key words: anagrelid (Thromboreductin®) - Ph-myeloproliferative diseases - registry - thrombosis.

Increased mean platelet volume and immature platelet fraction as potential predictors of thrombotic complications in BCR/ABL-negative myeloproliferative neoplasms.

BCR/ABL-negative myeloproliferative neoplasms (MPNs) are considered to be acquired thrombophilic conditions. Persistently enhanced platelet activation has been described in polycythaemia vera and essential thrombocythaemia (ET), and shown to contribute to a higher risk of arterial and venous thrombotic complications. Recent studies have shown that mean platelet volume (MPV) and immature platelet fraction (IPF) can serve as useful markers of platelet activation and increased risk of thrombosis. The aim of the present study was to investigate the relationship between these parameters and thrombotic events in BCR/ABL-negative MPN. MPV values in patients with BCR/ABL-negative MPN were significantly higher than MPV values of healthy individuals (P < 0.001). No significant difference in MPV or IPF was observed between groups of patients with and without thrombotic complications (P = 0.441; P = 0.110); the difference in IPF values was close to the significance level for patients with ET (P = 0.073). Higher values of IPF were more frequently detected in patients with JAK2 V617F positivity (P = 0.030). These patients had higher MPV more frequently than others, and this difference was close to the significance level (P = 0.056). Further studies should validate the use of platelet parameters to identify patients at high risk.

Second malignancies in philadelphia-negative myeloproliferative neoplasms-single-center experience.

AIM: The aim of this work was to retrospectively analyze patients with Philadelphia-negative myeloproliferative neoplasms through evaluation of frequency and characteristics of second malignancies (other than acute leukaemia and myelodysplastic syndrome). PATIENTS AND METHODS: Records of 172 patients were reviewed; an analysis was performed on data from 66 patients treated with hydroxyurea, 105 patients treated with other cytoreductive therapy, and 25 patients without treatment. RESULTS: A higher occurrence of second malignancies was found in the group treated with hydroxyurea (7.6%; other cytoreduction: 1.2%; without therapy: 0). After a median follow-up of 89 months in the hydroxyurea group, 13 patients developed second cancer during hydroxyurea therapy, located on the skin (68.75%) and other sites (31.25%). CONCLUSION: The incidence of second malignancies during hydroxyurea therapy in our cohort patient was significantly higher than the incidence of malignancies in the Czech population of corresponding age.