The association of JAK2^V617F mutation and leukocytosis with thrombotic events in essential thrombocythemia

Objectives: The Janus kinase 2 mutation, JAK2 (V617F), and megakaryocytic mutations, MPL (W515L/K), have been identified and correlated with a subtype of essential thrombocythemia (ET) patients. We investigated the frequency of mutations in ET patients and analyzed the relationship with their clinical features. Methods: Fifty-three ET patients were enrolled in the study. The amplification refractory mutation system was applied for the mutation survey of the JAK2^V617F, while the polymerase chain reaction with sequencing was used for the mutation survey of MPL^W515L/K. Results: Thirty-five (66%) patients harboring the JAK2 ^V617F mutation, including 3 homozygous and 32 heterozygous changes, but no MPL^W515L/K mutation, were found. During follow-up, 17 (32.1%) patients suffered from documented thrombotic events, with 15 having JAK2^V617F mutations. Statistical analysis showed that patients with the JAK2 mutation had significantly higher leukocytes, hemoglobin level, and thrombotic event (p = 0.043, p = 0.001, and p = 0.029, respectively). Thrombotic events were also significantly correlated with leukocytosis and older age. Conclusions: The JAK2^V617F mutation was noted in a certain population of ET patients and correlated with leukocytosis, high hemoglobin level, and thrombosis. Therefore, detection of the JAK2^V617F mutation can affect not only the diagnosis, but also the management of ET patients.