The association of JAK2V617F 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 MPLW515L/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. (C) 2007 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc.