Poster Session I: Myeloproliferative neoplasms - Clinical
Thrombosis is one of the major causes of morbidity and mortality in patients with chronic phase myeloproliferative neoplasms (MPN) comprising polycythemia vera (PV) and essential thrombocythemia (ET). The JAK2 V617F mutation is the most common driver mutation in BCR-ABL1 negative MPNs and the presence of JAK2 V617F is an independent risk factor of thrombotic events in patients with ET.
In this study, we analyzed whether the JAK2 V617F allele burden is associated with the incidence of thrombosis in JAK2 V617F-positive patients with PV or ET.
This was a retrospective study that assessed the impact of JAK2 V617F allele burden on clinical and laboratory characteristics in JAK2 V617F-positive patients with PV or ET. Patients with a diagnosis of PV or ET according to the WHO criteria at Daegu Catholic University Hospital between 2008 and 2018 were included in this study. JAK2 V617F allele burden were measured by pyrosequencing.
A total of 127 patents, median age 68 years, with PV (n = 61) or ET (n = 66) were included in our analyses. The JAK2 V617F allele burden in the entire population of patients was 45.0 ± 25.9%. A higher V617F allele burden was associated with higher white blood cell counts, higher hemoglobin values, lower platelet counts and higher LDH level (p < 0.001, p < 0.001, p = 0.001, and p = 0.001, respectively). There was a statistically significant difference in the JAK2 V617F allele burden between PV and ET (p < 0.001). The median V617F allele burden in PV patients was 58%, and ET was 30%. Thrombotic events were observed in 27.8% and 51.5% in patients with PV and ET, respectively. Multivariate logistic regression analysis revealed that older age (odds ratio, 1.07; 95% CI 1.01-1.18) was associated with higher incidence of thrombosis in patients with PV. In patients with ET, multivariate logistic regression analysis revealed that older age (odds ratio, 1.36; 95% CI 1.14-1.72), higher hemoglobin (odds ratio, 1.26; 95% CI 1.09-1.54), and V617F allele burden≥30% (odds ratio, 1.03; 95% CI 1.00-1.08) was elucidated as risk factors for thrombotic complications.
JAK2 V617F allele burden can represent the disease phenotype. The incidence of thrombotic complications in ET patients with high JAK2 V617F allele burden is significantly higher than patients with low JAK2 V617F allele burden. There was no significant difference of the rate of thrombosis in PV patients according to the JAK2 V617F allele burden.