Abstract: Objective:To investigate the distribution of JAK2V617F mutation in the patients with myeloproliferative neoplasms (MPN), to explore the association between JAK2V617F mutation and the clinical features of MPN, and to clarify its clinical significance in the diagnosis and treatment of the MPN patients. Methods:A total of 170 patients with MPN were selected as the subjects and divided into true polycythemia (PV) group (n=68), primary thrombocytopenia (ET) group (n=88) and primary myelofibrosis (PMF) group (n=14).The JAK2V617F mutations in 170 patients with MPN were detected by allele-specific PCR (AS-PCR). The differences in gender, age, white blood cell count, hemoglobin,platelet count, prothrombin time(PT),activated partial thromboplastin time(APTT), D-dimer, whether complicated with splenomegaly and thromboembolism of the JAK2V617F mutant-type and wild-type patients in each group were analyzed. Results:The total mutation rate of JAK2V617F mutation in 170 patients with MPN was 68.2% (116/170),and the mutation rates in PV, ET, and PMF groups were 72.1% (49/68), 68.1% (60/88), and 50.0% (7/14), respectively.The JAK2V617F mutation rate in PV group was higher than those in the other two groups, but there were no statistical differences(P=0.281). Compared with wild type group, the age of onset, the white blood cell and platelet counts of the PV patients with JAK2V617F mutation were significantly increased(P<0.01), PT and APTT were significantly prolonged(P<0.01), and the incidence of splenomegaly was increased (P<0.05); the white blood cell count of the the ET patients with JAK2V617F mutation was increased(P<0.01),the hemoglobin level was decreased(P<0.01), APTT was significantly prolonged(P<0.01), and the incidence of thromboembolic events was increased (P<0.05); the age of onset, the white blood cell and platelet counts of the PMF patients with JAK2V617F mutation were signficantly increased (P<0.05 or P<0.01).Compared with the ET and PMF patients with JAK2V617F mutation, APTT in the PV patients with JAK2V617F mutation was significantly prolonged(P<0.05). Compared with the JAK2V617F mution PV and ET patients, the age of onset and white blood cell count of the PMF patients with JAK2V617F mutation were increased(P<0.05). Conclusion:The clinical characteristics of the MPN patients with JAK2V617F mutation are significantly different from those in the wild-type patients. The clinical features of PV, ET and PMF in the patients with JAK2V617F mutation are also different. The PV patients with JAK2V617F mutation are more prone to APTT prolongation. The PMF patients with JAK2V617F mutation have the higher onset age and the white blood cell count.

Key words: myeloproliferative neoplasms, JAK2V617F mutation, white blood cell count, activated partial thromboplastin time, thrombosis