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Background: Primary myelofibrosis (PMF) is a chronic clonal myeloid disorder. Together with essential thrombocythemia (ET) and polycythemia vera (PV), it belongs to a group of Philadelphia chromosome-negative myeloproliferative neoplasms. Thrombotic events are serious complications negatively influencing the quality and length of these patients' lives. The confirmed risk factors for venous thromboembolism are age over 60 years, a positive history of thromboembolism, presence of common cardiovascular risks, JAK2 V617F mutation and, according to some authors, leukocytosis. Various opinions on the role of thrombocythemia have been published. The present study was undertaken to evaluate the benefit of thrombin generation test and its potential use in predicting the risk of thrombosis in MF patients., Methods: The analysis included plasma samples obtained from 36 patients diagnosed with MF in our center from 2004 to 2016 (JAK2 V617-positive 53%; CALR-positive 31%; MPL-positive 14%; triple negative 2%) and a control group comprising 20 healthy volunteer blood donors. Thrombin generation was measured in platelet-rich plasma using the TECHNOTHROMBIN® TGA kit (Technoclone, Austria) and the fully automated system Ceveron® Alpha (Technoclone). The results were correlated with clinical and laboratory parameters of the patients., Results: There were differences in thrombin generation as expressed by endogenous thrombin potential (ETP) between patients and healthy controls, with ETP being lower in the patient group (p = 0.0003). Analysis confirmed a significant correlation between thrombin generation and platelet counts, with higher thrombin generation in patients with thrombocythemia > 400 x 109/L (p = 0.04). ETP values were consistently higher in earlier disease stages and lower in CALR-mutated myelofibrosis., Conclusions: In MF patients, thrombin generation is mainly influenced by platelet counts and, to a lesser extent, by mutation status, activity, and progression of the disease. Thrombin generation test results have confirmed that thrombocythemia is a potential risk factor for thrombotic complications.

Background: In this part of the study, where we determined the causes of preeclampsia and other obstetric complications, we focused on the role of tissue factor (TF) in the activation of these pathophysiological processes. Recent findings attribute a significant part of the activation of coagulation creation of autoantibodies. Once this mechanism is activated, the antibodies induce expression of tissue factor (TF, CD142) on monocytes and vascular endothelial cells., Methods: We have proposed a monitor activation model of the coagulation system in preeclampsia and other pregnancy complications using TF expression on monocytes by flow cytometry and simultaneous determination the TF-induced thrombin generation in plasma. To determine expression of tissue factor (CD142) on monocytes, we proposed a method of multicolor flow cytometry using anti CD45 PerCP, anti CD14 APC, anti CD16b FITC, and anti CD142 PE antibodies and the corresponding isotype controls., Results: We verified the model on patients with severe antiphospholipid syndrome, which is a high expression of antibodies, in particular against beta-2GPI., Conclusions: We demonstrated complete inhibition of TF expression on monocytes and a significant reduction of thrombin generation in plasma.

The effect of direct oral anticoagulants (DOACs) on laboratory tests dependent on the production of their targets, factor IIa and factor Xa (FXa), is a well-known problem and can cause both false positive and negative results. Therefore, the correct interpretation of tests performed in patients receiving DOACs is necessary to avoid misclassification and subsequent clinical consequences. However, even with significant experience, there are situations where it is not possible to assess the influence of some methods. Particularly important is the situation in the diagnosis of lupus anticoagulants using the dilute Russell viper venom timetest, which is based on direct FXa activation. A very promising solution to this situation is offered by the DOAC laboratory balancing procedure DOAC-Stop. For evaluating the effectiveness of this procedure, 60 (20 apixaban, 20 dabigatran, and 20 rivaroxaban) patients treated with DOACs were enrolled. All patient samples were analyzed for the presence of individual DOAC types and subsequently subjected to the DOAC-Stop procedure. We evaluated its effectiveness by our own highperformance liquid chromatography-coupled tandem mass spectrometrymethod, which simultaneously sets all high-sensitivity DOACs. Unlike coagulation tests based on the determination of the residual effects of DOACs on target enzymes, which is complicated by extensive interindividual variation, this methodology is highly specific and sensitive. The DOAC-Stop procedure eliminated dabigatran from 99.5%, rivaroxaban from 97.9%, and apixaban from 97.1% of participants in our group. Residual amounts did not exceed 2.7 ng/mL for dabigatran, 10.9 ng/mL for rivaroxaban, or 13.03 ng/mL for apixaban, which are safe values that do not affect either screening or special coagulation tests. [ABSTRACT FROM AUTHOR]