Effect of JAK2 V617F on thrombotic risk in patients with essential thrombocythemia: measuring the uncertain

Abstract Background: the Registro Italiano Trombocitemia, that is a GIMEMA project, has been activated to registry Italian Essential Thrombocythemia (ET) patients, to improve the diagnosis appropriateness (WHO criteria), to verify the prognostic value of the clinical and biological parameters, to evaluate the compliance to the therapeutical Italian guidelines (1), and to create a network for activation of new studies. Objective: this analysis is mainly devoted to describe the ET patients registered in the RIT and to evaluate the therapeutic approach adopted in the 102 participating hematological centers. Material and methods: two thousand and fifteen ET patients have been registered after the written informed consent was obtained, and data validation by various expert panels is in progress. This preliminary report considers 1785 patients, diagnosed mainly (1078, 60.4%) since the publication in the year 2004 of the ET therapy Italian guidelines (1). Results: the patients, 678 (38%) males and 1107 (62%) females, showed at diagnosis: age 60.3 ± 16.8 years with higher values in males than in females (61.7 ± 15.3 vs. 59.4 ± 17.7, p<0.05), being the patients below 40 years 14% and those over 70 years 33% of cases; PLT count (109/L) 846 ± 309 with lower values in males than in females (813 ± 261 vs. 866 ± 334, p<0.002), and with values 1001–1500 and over 1500 in 16% and 4% of cases, respectively; WBC count (109/L) 9.1 ± 2.9, without difference by sex, and with values 12–15 in 10% and over 15 in 3% of cases; Hgb (g/dL) 14.2 ± 1.6 with higher values in males than in females (14.8 ± 1.5 vs. 13.8 ± 1.5, p<0.001), and with values over 16.5 in 8.5% of males and 2.7% of females, respectively; splenomegaly in 488 (27%), echo-documented in 324 cases (18%); history of hemorrhage and thrombosis in 90 (5%) and 325 (19%) of cases, respectively; disease-related symptoms in 41% and general thrombotic risk factors in 93% of cases, respectively. The WHO 2001 diagnostic criteria were reported for 33% of cases observed before the year 2004 and for 53 % of cases observed since the year 2004. Detailed data at diagnosis were reported as follows: bone marrow biopsy in 1087 cases (61%) with a frequency of 51% and 68% before and since the year 2004, respectively; bcr-abl study in 1045 cases (59%); cytogenetics in 828 cases (46%) with karyotype abnormalities in 27 patients (3%). The JAK2 V617F mutation, searched in 574 cases (32%), was observed in 320 of them (56%). The patient follow-up was 4.5 ± 4.5 years with a total of 5245 pt-yrs. During the follow-up the hemorrhagic events were 5.7% (1.3/100 pt-yrs), being the major events 1.9% (0.4/100 pt-yrs); the thrombotic complications were 14.9 % (3.3/100 pt-yrs), resulting the major arterial 9.4% (2.1/100 pt-yrs), the major venous 3.5% (0.8/100 pt-yrs) and the minor thrombosis 2% (0.4/100 pt-yrs). An antiplatelet treatment, almost always with low dose aspirin, was performed in 75% of the patients, without significant difference in the cases diagnosed before and since the 2004. A cytoreductive treatment was done with use of Hydroxyurea (HU, 64%), Interferon alpha (IFN, 16%), Anagrelide (ANA, 15%), Busulfan (BUS, 4%), and Pipobroman (PIPO, 2 %). In the ET patients diagnosed since the year 2004 respect those diagnosed before, it was observed a decrease in the use of all the cytoreductive drugs, particularly BUS (−62%), IFN ((−62%), and ANA ((−68%). The use of the cytoreductive drugs was related to the patient mean age (years): BUS (76), PIPO (72), HU (67), ANA (53), IFN (48). In the patients diagnosed since the 2004 as compared with those before 2004, the mean age of the treated patients increased for BUS (from 69 to 81 yrs, p<0.001) and for HU (from 64 to 69 yrs, p<0.001) while it decreased for IFN (from 49 to 46 yrs, p<0.05). Conclusion: in the analyzed patients of the ET Italian registry the diagnosis appropriateness resulted improved in the cases observed since the year 2004 respect those observed before, with an increase of bone marrow biopsies from 51% to 68% of patients. Moreover, in accord with the ET therapy Italian guidelines, the use of the cytoreductive drugs was less frequent in the patients diagnosed since the year 2004 than before (particularly for BUS, IFN, and ANA) and the more safe molecules IFN and ANA were preferentially deserved to the younger patients.

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Polymorphisms of NOS3 and FCGR2A Genes Contribute to Thrombotic Risk in Essential Thrombocythemia

Blood ◽

10.1182/blood.v110.11.1537.1537 ◽

2007 ◽

Vol 110 (11) ◽

pp. 1537-1537

Author(s):

Damla Olcaydu ◽

Heinz Gisslinger ◽

Harald Esterbauer ◽

Franz Wiesbauer ◽

Robert Kralovics

Keyword(s):

Nitric Oxide ◽

Essential Thrombocythemia ◽

Genetic Factors ◽

Jak2 V617f ◽

Candidate Snps ◽

Thrombotic Risk ◽

Mortality And Morbidity ◽

Clinical Variables ◽

Individual Snps ◽

Fv Leiden

Abstract Thrombosis is the most frequent complication in essential thrombocythemia (ET) that impairs quality of life and contributes to mortality and morbidity of patients. The molecular basis of thrombosis in ET remains unclear. Polymorphisms (SNPs) in coagulation factors (FII-G20210A, FV-Leiden) and the V617F mutation of JAK2 gene (JAK2-V617F) have previously been shown to associate with thrombosis in ET. Since thrombosis occurs frequently in JAK2-V617F negative ET and FII-G20210A and FV-Leiden polymorphisms occur only in up to 5% of patients, we examined the hypothesis that other genetic factors contribute to the thrombotic risk in ET. In addition to FII-G20210A and FV-Leiden we studied thirteen candidate SNPs of genes involved in coagulation (F7, F13A1, VWF, THSD1, ATIII), platelet aggregation (P2Y12, GPIIIA, GPIIB, FCGR2A) and endothelial function (NOS3, ADRA2B) previously implicated in thrombosis in non-MPD patients. We studied 94 patients with the diagnosis of ET retrospectively observed for clinical variables such as venous and arterial thrombosis, stroke, myocardial infarction, deep vein thrombosis (DVT), bleeding, angina pectoris, superficial venous thrombosis (SVT), and pulmonary embolism. SNP genotyping was performed using allele-specific PCR and sequencing. We examined the association of individual SNPs with the presence or absence of clinical variables (adjusted for age, sex, and BMI). In our ET cohort, JAK2-V617F showed significant correlation with the presence of DVT (OR 10.08; 95%CI 1.15–88.49; P=0.01). Both FII-G20210A and FV-Leiden were rare in this cohort (2% and 4%, respectively) and thus did not show any significant associations. Homozygosity for the 298Asp variant of NOS3 gene (encoding the endothelial nitric oxide synthase) showed significant correlation with stroke (OR 46.75, 95%CI 1.38–147, P=0.014). Similarly, homozygosity for the 131Arg variant of Fc receptor gamma 2A (FCGR2A) involved in platelet GPVI signaling correlated with the presence of SVT (OR 9.46, 95%CI 1.48–60.82, P=0.014). Our results indicate that genetic factors other than JAK2-V617F, FII-G20210A and FV-Leiden contribute to thrombotic risk in ET. Furthermore, the nitric oxide and the platelet GPVI signaling pathways are likely to play an important role in the pathogenesis of thrombosis in ET.

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Procoagulant Platelet-Derived Microparticles Are Lower in Calreticulin-Than in-JAK2-Mutated Essential Thrombocythemia

Blood ◽

10.1182/blood.v124.21.110.110 ◽

2014 ◽

Vol 124 (21) ◽

pp. 110-110 ◽

Cited By ~ 1

Author(s):

Agnes Charpentier ◽

Nathalie Cambier ◽

Anne Bauters ◽

Nathalie Trillot ◽

Matthieu Wemeau ◽

...

Keyword(s):

Essential Thrombocythemia ◽

Lower Risk ◽

Conflicts Of Interest ◽

Myeloproliferative Neoplasm ◽

Jak2 V617f ◽

Procoagulant Activity ◽

P Value ◽

Thrombotic Risk ◽

Testing Procedures ◽

Increased Risk

Abstract Rationale: Essential Thrombocythemia (ET) is a Philadelphia-negative myeloproliferative neoplasm characterized by an increased risk of thrombosis. Previous reports suggest a role for microparticles (MP) in the pathogenesis of thrombosis in ET. MPs are small plasma membrane vesicles bearing potent procoagulant proteins and phospholipids. They are released into the circulation by various blood and endothelial cells after cellular activation and/or apoptosis. The recently described somatic calreticulin (CALR) exon 9 mutations in almost 20% of ET defines a lower-risk thrombosis ET subtype. We extensively studied phenotype and procoagulant activity of plasma MPs in order to assess MP contribution to the thrombotic risk in CALR versus JAK2 (V617F) mutated ET patients. Patients and methods: We analyzed MP count, phenotype and procoagulant activity in 45 JAK2 V617F+ and 15 CALR+ consecutive and newly diagnosed ET patients in accordance to WHO criteria recruited between november 2010 and april 2013. After given informed consent, blood samples were obtained in all patients before initiating any cytoreductive therapy. Pre-analytical and testing procedures complied with the recommendations of the ISTH Standardization Sub-Committee and each test was performed in duplicate . Using flow cytometry (FC500 flow-cytometer, Beckman-Coulter), MPs were characterized and measured in platelet-free plasma samples. MPs were characterized by their size and co-expression of bound Annexin V and the following cell-specific monoclonal antibodies: CD41 (Platelet-MP, PMP), CD235a (Red cell-MP, RMP), CD14 (Monocytes-MP, MoMP), CD11b (Granulocytes-MP, GMP), CD144 (Endothelial-MP, EMP), CD62P and CD41 (P-Selectin+ PMP), CD142 and CD41 (Tissue Factor (TF)+ PMP, TF+PMP). MP-associated procoagulant activity was also measured using a-thrombin generation assay (Zymuphen MP-activity). Statistical analysis was performed with SPSS software. Results are expressed as median [interquartile range]. Results: Patients characteristics: The platelet count (109/L) was higher in CALR+ than in JAK2+ patients (866 [666 – 918], 659 [571 – 807] respectively, p= 0.049), and all other clinical and hematological characteristics were also distributed in agreement with previous reports. Furthermore, CALR+ patients were preferentially distributed in the lower risk categories of the IPSET-thrombosis and IPSET-survival scores than in JAK2+ patients (p<0.00001 and p= 0.04 respectively). The main results are summarized in table 1. MP count and MP/Platelets ratio were significantly lower in CALR+ than in JAK2+ patients. PMP count, PMP percentage of all MPs and PMP/Platelets ratio were lower in CALR+ than in JAK2+ patients. Furthermore, CALR+ patients had lower PMP surface P-Selectin. MP-associated procoagulant activity/Platelets ratio was significantly lower in CALR+ than in JAK2+ patients. There were no significant differences in TF-carrying PMP or in other cell-derived MP (RMP, MoMP, GMP, EMP). Conclusion: Our results demonstrate a decreased in circulating procoagulant PMP in CALR+ ET-patients compared to JAK2+ patients and lower platelet activation in CALR+ ET patients as measured by P-Selectin expression on PMP. Thus, as CALR+ patients have lower thrombotic-risk according to the literature and the IPSET-survival and IPSET-thrombosis scores observed in our study, the lower level of procoagulant PMP could account, at least in part, for a lower thrombotic risk of CALR+ ET patients. Table 1 main results CALR + JAK2 V617F + p value MP (/µL) 3289 [1662-4240] 4961 [2697-6687] 0.04 MP/Platelets 3.6 [2.8-5.3] 6.9 [4.7-9.6] 0.01 PMP (/µL) 3100 [20683887] 5702 [3423-10257] 0.004 PMP/Platelets 3.38 [2.976.33] 7.55 [5.1212.66] 0.002 % PMP 90 [8492] 93 [9096] 0.03 MP-activity(nM)/platelet 0.015 [0.0080.028] 0.029 [0.0190.041] 0.05 P-Selectin+ PMP (/µL) 195 [152-219] 747 [383-965] 0.001 RMP (/µL) 4 [1.78.2] 4 [2.59.7] ns MoMP (/µL) 43 [2752] 74.5 [22135] ns GMP (/µL) 31.5 [2448] 30 [1155] ns EMP (/µL) 99.4 [32110] 95.6 [51140] ns TF+ PMP (/µL) 22.3 [9.8115] 27.1 [20.894.4] ns Disclosures No relevant conflicts of interest to declare.

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Updates in the management of polycythemia vera and essential thrombocythemia

Therapeutic Advances in Hematology ◽

10.1177/2040620719870052 ◽

2019 ◽

Vol 10 ◽

pp. 204062071987005 ◽

Cited By ~ 6

Author(s):

Prithviraj Bose ◽

Srdan Verstovsek

Keyword(s):

Polycythemia Vera ◽

Essential Thrombocythemia ◽

Myeloproliferative Neoplasms ◽

Philadelphia Chromosome ◽

Unmet Need ◽

Gene Mutations ◽

Jak2 V617f ◽

Additional Contribution ◽

Thrombotic Risk ◽

Targeted Next Generation Sequencing

Polycythemia vera (PV) and essential thrombocythemia (ET) are both classic, relatively indolent, chronic Philadelphia-chromosome-negative (Ph−) myeloproliferative neoplasms (MPNs) characterized by elevated blood counts, thrombotic as well as hemorrhagic tendencies, a variety of symptoms, cumulative risks of progression to myelofibrosis and transformation to acute myeloid leukemia over time, and long survival. Molecularly, PV is more homogenous, being driven by JAK2 mutations in virtually all cases, while ET can be JAK2-, CALR-, or MPL-mutated, as well as ‘triple negative’. Recent targeted next-generation sequencing efforts have identified other, nondriver gene mutations, some with prognostic relevance. Prevention of thrombotic and hemorrhagic complications continues to be the major focus of management, although symptoms are increasingly being recognized as a relatively unmet need, particularly in ET. Thrombotic risk stratification in PV is still based on age and history of thrombosis, while in ET, the additional contribution of JAK2 V617F to thrombotic risk is now well established. The associations of leukocytosis with clotting risk (in both conditions) and mortality (in PV) have drawn increased attention with the availability of ruxolitinib as a second-line treatment in PV. Similarly, there is a renewed interest in interferons with the emergence of ropeginterferon alfa-2b as a potential new frontline treatment option in PV. Drug development is more difficult in ET, the most indolent of the classic Ph− MPNs, but ruxolitinib is being studied. Triggering apoptosis via the p53 pathway through pharmacologic inhibition of human double minute 2 (and synergism with interferon) is a new, promising therapeutic strategy.

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Influence of the JAK2 V617F mutation and inherited thrombophilia on the thrombotic risk among patients with essential thrombocythemia

Haematologica ◽

10.3324/haematol.13869 ◽

2009 ◽

Vol 94 (5) ◽

pp. 733-737 ◽

Cited By ~ 37

Author(s):

V. De Stefano ◽

T. Za ◽

E. Rossi ◽

A. Fiorini ◽

A. Ciminello ◽

...

Keyword(s):

Essential Thrombocythemia ◽

Jak2 V617f ◽

Jak2 V617f Mutation ◽

Thrombotic Risk ◽

Inherited Thrombophilia ◽

V617f Mutation

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Essential Thrombocythemia in Young Individuals: Frequency and Risk Factors for Vascular Events and Evolution to Myelofibrosis in 126 Patients.

Blood ◽

10.1182/blood.v108.11.3598.3598 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3598-3598

Author(s):

Alberto Alvarez-Larran ◽

Francisco Cervantes ◽

Beatriz Bellosillo ◽

Manuel Giralt ◽

Antoni Julia ◽

...

Keyword(s):

Essential Thrombocythemia ◽

Young Patients ◽

Rare Event ◽

Vascular Complications ◽

Jak2 V617f ◽

Rank Test ◽

Vascular Events ◽

Thrombotic Risk ◽

Free Survival ◽

Probability Of Survival

Abstract Vascular events and evolution to either myelofibrosis (MF) and acute leukemia (AL) are the main causes of morbidity and mortality in individuals with essential thrombocythemia (ET). However, the frequency of these complications in young ET patients is not well known. The objective of the present study was to assess the frequency of vascular events and the incidence of MF and AL in young patients with ET and to identify the factors associated with the development of such complications. In 126 subjects diagnosed with ET at a median age of 31 years (range: 5–40), overall survival and probability of survival free of either thrombosis, bleeding, MF, AL, and polycythemia vera (PV) were analyzed by the Kaplan-Meier method, followed by the log-rank test. With a median follow-up of eleven years (range: 4–25) three patients have died, being the probability of survival 98% at ten years. A total of 31 thrombotic events were registered in 25 patients; thrombosis-free survival (TFS) was 84% at ten years. Tobacco use was the only factor associated with an increased thrombotic risk, since TFS at 10 years was 72% in smokers versus 90% in non-smokers (p=0.03). Severe hemorrhagic complications were observed in 11 patients, and the estimated probability of bleeding-free survival was 92% at ten years. Evolution to MF was seen in 6 patients, four of whom had never received treatment for ET. MF-free survival was 97% at 10 years, with the risk being higher in patients showing an increased reticulin network in the bone marrow biopsy performed at diagnosis of ET (p=0.005). Transformation to AL was registered in one patient. JAK2 was mutated in 33 out of the 87 assessable patients (38%) and the mutation was associated with higher Hb values at diagnosis (p = 0.001). ET evolved into PV in five patients, being the probability of evolution into PV of 15% in JAK2 V617F positive patients versus 0% in JAK2 V617F negative patients (p=0.01). In conclusion, severe vascular complications are not infrequent in young subjects with ET, whereas transformation to MF or AL is a rare event.

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Decision letter for "Comparison between thrombotic risk scores in essential thrombocythemia and survival implications"

10.1002/hon.2670/v1/decision1 ◽

2019 ◽

Keyword(s):

Essential Thrombocythemia ◽

Risk Scores ◽

Thrombotic Risk

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Increased Thromboxane Biosynthesis in Essential Thrombocythemia

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649916 ◽

1995 ◽

Vol 74 (05) ◽

pp. 1225-1230 ◽

Cited By ~ 71

Author(s):

Bianca Rocca ◽

Giovanni Ciabattoni ◽

Raffaele Tartaglione ◽

Sergio Cortelazzo ◽

Tiziano Barbui ◽

...

Keyword(s):

Platelet Count ◽

Platelet Activation ◽

Essential Thrombocythemia ◽

Therapeutic Strategy ◽

Low Dose ◽

Thrombotic Risk ◽

Dose Aspirin ◽

Gender And Age ◽

Low Dose Aspirin

SummaryIn order to investigate the in vivo thromboxane (TX) biosynthesis in essential thromboeythemia (ET), we measured the urinary exeretion of the major enzymatic metabolites of TXB2, 11-dehydro-TXB2 and 2,3-dinor-TXB2 in 40 ET patients as well as in 26 gender- and age-matched controls. Urinary 11-dehydro-TXB2 was significantly higher (p <0.001) in thrombocythemic patients (4,063 ± 3,408 pg/mg creatinine; mean ± SD) than in controls (504 ± 267 pg/mg creatinine), with 34 patients (85%) having 11-dehydro-TXB2 >2 SD above the control mean. Patients with platelet number <1,000 × 109/1 (n = 25) had significantly higher (p <0.05) 11 -dehydro-TXB2 excretion than patients with higher platelet count (4,765 ± 3,870 pg/mg creatinine, n = 25, versus 2,279 ± 1,874 pg/mg creatinine, n = 15). Average excretion values of patients aging >55 was significantly higher than in the younger group (4,784 ± 3,948 pg/mg creatinine, n = 24, versus 2,405 ± 1,885 pg/mg creatinine, n = 16, p <0.05). Low-dose aspirin (50 mg/d for 7 days) largely suppressed 11-dehydro-TXB2 excretion in 7 thrombocythemic patients, thus suggesting that platelets were the main source of enhanced TXA2 biosynthesis. The platelet count-corrected 11-dehydro-TXB2 excretion was positively correlated with age (r = 0.325, n = 40, p <0.05) and inversely correlated with platelet count (r = -0.381, n = 40, p <0.05). In addition 11 out of 13 (85%) patients having increased count-corrected 11-dehydro-TXB2 excretion, belonged to the subgroup with age >55 and platelet count <1,000 × 1099/1. We conclude that in essential thrombocythemia: 1) enhanced 11-dehydro-TXB2 excretion largely reflects platelet activation in vivo;2) age as well as platelet count appear to influence the determinants of platelet activation in this setting, and can help in assessing the thrombotic risk and therapeutic strategy in individual patients.

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