In Philadelphia chromosome-negative chronic myeloproliferative neoplasia, i.e. polycythemia vera, essential thrombocythemia and primary idiopathic myelofibrosis enhanced risk of thrombosis could be connected with Janus kinase 2 gene mutation occurring in various frequency in these diseases (JAK2V617F). Since 2002 the presence of JAK2 mutation in chronic myeloproliferative neoplasia has been regularly detected.
Aims: In a retrospective survey the possible connection between JAK2 mutation and thrombosis was analyzed in patients with chronic myeloproliferative neoplasia subgroups cared and treated in their hospital and outpatient departments.
Patients and methods: Between 2007-2010 peripheral blood samples of 171 patients with chronic myeloproliferative neoplasia (68 patients of polycythemia vera, 84 of essential thrombocythemia and 19 ones with primary idiopathic myelofibrosis) were sent to several molecular biological laboratories, where V617F mutation from DNA specimens was detected by allele-specific polymerase chain reaction, as well. Thromboembolic complications (arterial, i.e. cerebro-and cardiovascular and venous thrombosis) occurred during course of illness of patients were registered. Statistical analysis was made by statistical software program for Windows.
Results: JAK2 mutation in 53 patients with polycythemia vera (77.9%) was detected, whilst in essential thrombocythemia 55 patients (65.4%) and in primary idiopathic myelofibrosis 7 patients (36.8%) proved to be JAK2 positive. In 18 JAK2 positive patients of polycythemia vera thromboembolic episodes were observed (18/53, 33.9%), whilst in essential thrombocythemia JAK2 mutational status was accompanied with thromboembolic events in 17/55 patients (30.9%). In the 7 JAK2 positive ones with primary idiopathic myelofibrosis thrombotic complication did not occurred. However, in JAK2 negative cases thrombotic events could also be detected (from 10 JAK2 negative patients with polycythemia vera in four ones, and in six with JAK2 negative 23 essential thrombocythemic patients.
Conclusions: Incidence of the JAK2 mutation in their patients with chronic myeloproliferative neoplasia subgroups mainly corresponds to the literary data. Thrombosis ensued both in JAK positive polycythemia vera and essential thrombocythemia cases occurred nearly in the same number, but the incidence of thrombosis ensued in JAK2 negative cases did not differ significantly from the JAK2 positive patients. From these results it could be suggested that the presence or absence of JAK2 mutation in the development of thrombosis has no predictive value in patients with chronic myeloproliferative neoplasia.