The evaluation of patients with essential thrombocythemia in terms of risk of thrombosis

Abstract

OBJECTIVE:The aim of this study was to compare the incidence of factors associated with an increased risk of thrombosis in patients with essential thrombocythemia.METHODS: A total of 200 patients followed-up in our unit with a diagnosis of essential thrombocythemia in 13 years were analyzed retrospectively.RESULTS: Of the study participants, 60.5% were females and 39.5% were males, with an overall mean (±SD) age of 54.93 (±14.21) years. In 119 patients, Janus Kinase 2 was positive with 56.3% of cases. When two patient categories were defined as those with or without history of thrombosis, no significant differences were found in terms of Janus Kinase 2 positivity, mean age, as well as white blood cells and platelet counts (p>0.05). Also, no significant differences in thrombotic event incidence were found between patient categories defined on the basis of cut-off values for white blood cells (cut-off values of 15×10 3 /mm 3 and 8.7×10 3 /mm 3 ) and platelets (cut-off values of 1500×10 3 /mm 3 ) (p>0.05).CONCLUSION: Although our results are generally in line with the published data, some divergence from previous results has been observed with respect to risk factors for thrombotic events. Absence of a correlation between leukocytosis and thrombosis may be related with the significant decline in white blood cells after treatment. Also, a significant reduction in platelet counts occurring in association with treatment is linked with a lowered incidence of thrombosis. Janus Kinase 2-positive patients had a similar thrombosis frequency with that reported in the literature.

Molecular landscape of the JAK2 gene in chronic myeloproliferative neoplasm patients from the state of Amazonas, Brazil

“…Furthermore, it has been highlighted that MPN is associated with a high risk of thrombotic and thromboembolic events when compared with the general population, and is also associated with increased hematopoietic counts (40), which was also observed in the present study. This fact may be explained by the presence of a high VAF of JAK2V617F (≥50%), which likely stimulates deregulation signaling in hematopoietic progenitor cells and may be potentialized by the presence of other variants in genes such as CALR and MPL; these are directly implicated in platelet activation and increased platelet account (40).…”

“…The effects of JAK2 VAF are well established; however, the specific populations affected are poorly understood. Through the comparison of JAK2V617F VAF, it was shown that patients from the state of Amazonas with PV had a JAK2V617F VAF that was higher than those diagnosed with ET, and individuals with a VAF of ≥50% had more thrombo-hemorrhagic events and a slight prolongation in coagulation tests, especially in PT-INR and aPTT when compared with those with a VAF of <50%, which is that not dissimilar to previous studies (40,46). This fact directly suggests that individuals with a high JAK2V617F VAF exhibit increased intracellular signaling, cellular activation, and possible alterations in coagulation factors, thus contributing to the deregulation of hemostasis.…”

“…This fact may be due to an increased platelet count with functional platelet disorders, such as impaired platelet aggregation response to collagen and reduced number of dense granules in platelets (45). In addition, current literature notes that ET is more common in females, and bleeding and thrombotic risks are the major complications in MPN patients (40,46). Nevertheless, female biology may play a role in the development of bleeding and thrombotic events, likely due to pregnancy and the use of contraceptives interfering with the interactions of platelets and other molecules in the endothelium.…”

Case report: Metastatic pancreatic neuroendocrine tumour associated with portal vein thrombosis; successful management with subsequent pregnancies

“…More than half of ET patients are JAK2V617F mutation-positive. According to our present knowledge, JAK2 mutation has been an independent factor for thromboembolic events; however, the precise mechanism remains unknown (3). Most ET patients enjoy a near-normal life expectancy (4).…”