Leukocytosis is a risk factor for thrombosis in essential thrombocythemia: interaction with treatment, standard risk factors, and Jak2 mutation status

Distinct clinico-molecular arterial and venous thrombosis scores for myeloproliferative neoplasms risk stratification

Current recommended risk scores to predict thrombotic events associated with myeloproliferative neoplasms (MPN) do not discriminate between arterial and venous thrombosis despite their different physiopathology. To define novel stratification systems, we delineated a comprehensive landscape of MPN associated thrombosis across a large long-term follow-up MPN cohort. Prior arterial thrombosis, age >60 years, cardiovascular risk factors and presence of TET2 or DNMT3A mutations were independently associated with arterial thrombosis in multivariable analysis. ARTS, an ARterial Thrombosis Score, based on these four factors, defined low- (0.37% patients-year) and high-risk (1.19% patients-year) patients. ARTS performance was superior to the two-tiered conventional risk stratification in our training cohort, across all MPN subtypes, as well as in two external validation cohorts. Prior venous thrombosis and presence of a JAK2V617F mutation with a variant allelic frequency ≥50% were independently associated with venous thrombosis. The discrimination potential of VETS, a VEnous Thrombosis Score based on these two factors, was poor, similar to the two-tiered conventional risk stratification. Our study pinpoints arterial and venous thrombosis clinico-molecular differences and proposes an arterial risk score for more accurate patients' stratification. Further improvement of venous risk scores, accounting for additional factors and considering venous thrombosis as a heterogeneous entity is warranted.

Perturbational phenotyping of human blood cells reveals genetically determined latent traits associated with subsets of common diseases

Although genome-wide association studies (GWAS) have successfully linked genetic risk loci to various disorders, identifying underlying cellular biological mechanisms remains challenging due to the complex nature of common diseases. We established a framework using human peripheral blood cells, physical, chemical and pharmacological perturbations, and flow cytometry-based functional readouts to reveal latent cellular processes and performed GWAS based on these evoked traits in up to 2,600 individuals. We identified 119 genomic loci implicating 96 genes associated with these cellular responses and discovered associations between evoked blood phenotypes and subsets of common diseases. We found a population of pro-inflammatory anti-apoptotic neutrophils prevalent in individuals with specific subsets of cardiometabolic disease. Multigenic models based on this trait predicted the risk of developing chronic kidney disease in type 2 diabetes patients. By expanding the phenotypic space for human genetic studies, we could identify variants associated with large effect response differences, stratify patients and efficiently characterize the underlying biology.

Clinical Phenotype and Outcomes of Pulmonary Hypertension Associated with Myeloproliferative Neoplasms: A Population-based Study

Rationale: Precapillary pulmonary hypertension (PH) is a rare and largely unrecognized complication of myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (MF). Objectives: To describe characteristics and outcomes of MPN-associated PH. Methods: We report clinical, functional, and hemodynamic characteristics, classification, and outcomes of patients with PV, ET, or primary MF in the French PH registry. Measurements and Main Results: Ninety patients with MPN (42 PV, 35 ET, 13 primary MF) presented with precapillary PH with severe hemodynamic impairment, with a median mean pulmonary arterial pressure and pulmonary vascular resistance of 42 mm Hg and 6.7 Wood units, respectively, and impaired clinical conditions, with 71% in New York Heart Association functional classes III/IV and having a median 6-minute-walk distance of 310 m. Half of the patients were diagnosed with chronic thromboembolic PH (CTEPH); the other half were considered to have group 5 PH. MF was preferentially associated with group 5 PH, whereas PV and ET were generally related to CTEPH. Proximal lesions were diagnosed in half of the patients with CTEPH. Thromboendarterectomy was performed in 18 selected patients with high risk of complications (5 early deaths). Overall survival at 1, 3, and 5 years was 67%, 50%, and 34% in group 5 PH and 81%, 66%, and 42% in CTEPH, respectively. Conclusions: PH is a life-threatening condition potentially occurring in MPN. There are multiple mechanisms, with equal diagnoses of CTEPH and group 5 PH. Physicians should be aware that PH strongly affects the burden of patients with MPN, especially in group 5 PH, with unknown pathophysiological mechanisms.

Antiphospholipid antibodies and the risk of thrombosis in myeloproliferative neoplasms

The morbidity and mortality of BCR-ABL-negative myeloproliferative neoplasia (MPN) patients is highly dependent on thrombosis that may be affected by antiphospholipid antibodies (aPLA) and lupus anticoagulant. Our aim was to evaluate the association of the aPLA together with platelet receptor glycoprotein (GP) Ia/IIa c.807C>T CT/TT genotypes and thrombotic complications in patients with MPNs. The study included 108 patients with BCR-ABL-negative MPN with data of previous thrombosis. Two different screening and one confirmatory test for the lupus anticoagulant were performed. Thrombotic complications were present in 59 (54.6%) subjects. aPLA were more frequently found in MPN patients with thrombosis vs no thrombosis (25.4 and 6.1%; p = 0.007). MPN patients with arterial thrombosis were more frequently positive for aPLA vs no arterial thrombosis (38.8 and 11.9%; p = 0.001). aPLA were more frequently found in patients with cerebrovascular events vs other arterial thrombotic complications or no thrombosis, respectively (39.3, 6.1, and 12.9%; p < 0.001). MPN patients with thrombosis were more frequently positive with aPLA and had platelet receptor GP Ia/IIa c.807C>T CT/TT genotypes compared to MPN patients without thrombosis (18.6 and 2.0%; p = 0.006). aPLA alone or with coexistence with platelet receptor GP Ia/IIa c.807C>T CT/TT polymorphism could be associated with thrombotic complications in patients with MPN.

Molecular Genetics of Thrombotic Myeloproliferative Neoplasms: Implications in Precision Oncology

Classical BCR-ABL-negative myeloproliferative neoplasms (MPN) include polycythaemia vera, essential thrombocythaemia, and primary myelofibrosis. Unlike monogenic disorders, a more complicated series of genetic mutations are believed to be responsible for MPN with various degrees of thromboembolic and bleeding complications. Thrombosis is one of the early manifestations in patients with MPN. To date, the driver genes responsible for MPN include JAK2, CALR, MPL, TET2, ASXL1, and MTHFR. Affords have been done to elucidate these mutations and the incidence of thromboembolic events. Several lines of evidence indicate that mutations in JAK2, MPL, TET2 and ASXL1 gene and polymorphisms in several clotting factors (GPIa, GPIIa, and GPIIIa) are associated with the occurrence and prevalence of thrombosis in MPN patients. Some polymorphisms within XRCC1, FBG, F2, F5, F7, F12, MMP9, HPA5, MTHFR, SDF-1, FAS, FASL, TERT, ACE, and TLR4 genes may also play a role in MPN manifestation. This review aims to provide an insightful overview on the genetic perspective of thrombotic complications in patients with MPN.

Neutrophils in aging and aging‐related pathologies

Over the past millennia, life expectancy has drastically increased. While a mere 25 years during Bronze and Iron ages, life expectancy in many European countries and in Japan is currently above 80 years. Such an increase in life expectancy is a result of improved diet, life style, and medical care. Yet, increased life span and aging also represent the most important non-modifiable risk factors for several pathologies including cardiovascular disease, neurodegenerative diseases, and cancer. In recent years, neutrophils have been implicated in all of these pathologies. Hence, this review provides an overview of how aging impacts neutrophil production and function and conversely how neutrophils drive aging-associated pathologies. Finally, we provide a perspective on how processes of neutrophil-driven pathologies in the context of aging can be targeted therapeutically.

Advances in Risk Stratification and Treatment of Polycythemia Vera and Essential Thrombocythemia

PURPOSE OF REVIEW

Estimating and modifying thrombotic risk is currently the mainstay of care for patients with polycythemia vera (PV) and essential thrombocythemia (ET). In recent years, however, increased attention has shifted towards quality of life and disease modification. In this review, we discuss recent advances in risk stratification, present updated results for ruxolitinib and interferon randomized clinical trials, discuss new approaches in antiplatelet and anticoagulant treatment, and summarize early phase trials of novel agents and emerging therapeutic concepts for the treatment of PV and ET.

RECENT FINDINGS

International collaborations and novel technologies, i.e., next-generation sequencing and machine learning techniques, have demonstrated excellent abilities to improve thrombotic risk stratification in PV and ET. Updated results from ruxolitinib and interferon randomized clinical trials have confirmed excellent efficacy and safety of these agents, both as first- and second-line treatments. Early trials of novel agents (histone deacetylase inhibitors, telomerase inhibitors, lysine-specific demethylase-1 inhibitors, human double-minute 2 inhibitors, and hepcidin mimetics) have shown encouraging efficacy and safety in blood count control, reduction of splenomegaly, and alleviation of disease-related symptoms. Finally, accumulating evidence suggested that direct oral anticoagulants may be a valid therapeutic alternative to warfarin for prolonged thromboprophylaxis. International collaborations ("big data") with the help of new technologies represent an exciting new approach to analyze rare outcomes in rare diseases, especially for identifying novel prognostic biomarkers in PV and ET. Randomized clinical trials are also needed to fully elucidate whether novel agents may establish new standards of care.

Survival and risk of vascular complications in myelofibrosis-A population-based study from the Swedish MPN group

OBJECTIVE

To gain knowledge of underlying risk factors for vascular complications and their impact on life expectancy in myelofibrosis.

METHODS

From a cohort of 392 myelofibrosis patients registered in the Swedish MPN registry 58 patients with vascular complications during follow-up were identified. Patients with vascular complications were compared with both 1:1 matched controls and the entire myelofibrosis cohort to explore potential risk factors for vascular complications and their impact on survival.

RESULTS

Incidence of vascular complications was 2.8 events per 100 patient-years and the majority of complications were thrombotic. Patients with complications were significantly older and had lower hemoglobin when compared to the entire cohort. In the case-control analysis, no significant risk factor differences were observed. The major cause of death was vascular complications and median survival was significantly impaired in patients with vascular complications (48 months) compared to controls (92 months). Inferior survival in patients with vascular complications was found to be dependent on IPSS risk category in a Cox regression model.

CONCLUSION

Vascular complications have a considerable impact on survival in MF. At diagnosis, risk assessment by IPSS does not only predict survival but is also associated with the risk of vascular complications.

Assessment of relation between JAK2 gene and thrombosis in myeloproliferative neoplasms

Background Thrombotic complications are the most considerable etiology causing morbidity and mortality in patients with philadelphia (Ph) negative myeloproliferative neoplasms (MPN). There are many studies evaluating the association of JAK2 mutation and risk of thrombosis in MPN with inconclusive results. We also investigated the relation between JAK2 mutation in all Ph negative MPN and thrombosis. Material and Methods Thrombotic events and demographic features of 177 patients with Ph negative MPN were evaluated retrospectively. Results JAK2 V617 F mutation was detected in 57% of patients with essential thrombocythemia (ET), %90.3 of pateints with polycythemia vera (PV), 100% of pateints with primary myelofibrosis (PMF). Thrombotic complications occured more frequently with JAK2 mutation in all MPN patients than without (p=0.014). In JAK 2 mutation positive groups, the median age, thrombosis risk scores and leucocyte values are higher, splenomegaly and arterial and/or venous thrombosis are detected more frequently (p

Microrheological disorders in patients with polycythemia vera suffered acute ischemic stroke

The relevance of the study is determined by the fact that the combination of cerebrovascular disorders and myeloproliferative diseases requires the search for a predictive biomarker to improve outcomes. The aim of this article was to explore the meanings of microrheological disorders in patients with polycythemia vera (PV) who suffered an acute ischemic stroke (AIS). The study was carried out at the Research center of Neurology. We studied microrheological properties in 181 patients (aged 42-75 years). From the AIS developed in 68 (38%) patients with PV; 59 (32%) patients with AIS were without PV; 54 (30%) patients with PV did not suffer AIS. Microrheological disorders, first of all, the red blood cells (RBC) deformability correlated to AIS severity and its features in comorbid patients. The RBC deformability was dependent on the allelic load of the V617F mutation in the JAK2 gene. Additionally, it was found that RBC deformability perform diagnostic value in the acute phase of ischemic stroke as well as get predictive value for thrombotic complications development within 2 years after AIS in such patients. We suppose that in patients with PV an ischemic stroke and thrombosis would directly depend on the success of PV treatment. In turn, RBC deformability is applicable for some predictive models to late thrombosis development.

Ιmmunity, Vascular Aging, and Stroke

Stroke is one of the most devastating manifestations of cardiovascular disease. Growing age, arterial hypertension, and atherosclerosis are identified as independent risk factors for stroke, primarily due to structural and functional alterations in the cerebrovascular tree. Recent data from in vitro and clinical studies have suggested that the immune system influences atherosclerosis, promoting vascular stiffness and vascular aging and contributing to ischemic stroke, intracranial haemorrhage and microbleeds, white matter disease, and cognitive decline. Furthermore, aging is related to a chronic low-grade inflammatory state, in which macrophage, neutrophils, natural killer (NK cells), and B and T lymphocytes act as major effectors of the immune-mediated cell responses. Moreover, oxidative stress and vascular inflammation are correlated with endothelial dysfunction, vascular aging, blood-brain barrier disruption, lacunar lesions, and neurodegenerative disorders. This review discusses the pathophysiological roles of fundamental cellular and molecular mechanisms of aging, including the complex interplay between them and innate immunity, as well as vascular dysfunction, arterial stiffness, atherosclerosis, atherothrombosis, systemic inflammation, and blood-brain barrier dysfunction.

Thrombotic and Hemorrhagic Issues Associated with Myeloproliferative Neoplasms

Thrombotic and hemorrhagic complications are related to a significant rate of morbidity and mortality in patients with myeloproliferative neoplasms (MPNs), they are therefore called “thrombohemorrhagic” syndromes. Several clinical factors, such as age and presence of cardiovascular comorbidities are responsible for thrombotic complications. High blood counts, platelet alterations, presence of JAK2 mutation and possibly of other CHIP mutations such as TET2, DNMT3A, and ASXL1, procoagulant microparticles, NETs formation, endothelial activation and neo-angiogenesis are some of the parameters accounting for hypercoagulability in patients with myeloproliferative neoplasms. Bleeding complications emerge as a result of platelet exhaustion. They can be also linked to a functional deficiency of von Willebrand factor, when platelet counts rise above 1000G/L. The mainstay of management consists on preventing hemostatic complications, by antiplatelet and/or anticoagulant treatment and myelosuppressive agents in high-risk patients.Circumstances related to a high thrombohemorrhagic risk, such as pregnancy and the perioperative period, prompt for specific management with regards to anticoagulation and myelosuppression treatment type. In order to apply a patient-specific treatment strategy, there is a need for a risk score assessment tool encompassing clinical parameters and hemostasis biomarkers.

The evaluation of patients with essential thrombocythemia in terms of risk of thrombosis

OBJECTIVE

The aim of this study was to compare the incidence of factors associated with an increased risk of thrombosis in patients with essential thrombocythemia.

METHODS

A total of 200 patients followed-up in our unit with a diagnosis of essential thrombocythemia in 13 years were analyzed retrospectively.

RESULTS

Of the study participants, 60.5% were females and 39.5% were males, with an overall mean (±SD) age of 54.93 (±14.21) years. In 119 patients, Janus Kinase 2 was positive with 56.3% of cases. When two patient categories were defined as those with or without history of thrombosis, no significant differences were found in terms of Janus Kinase 2 positivity, mean age, as well as white blood cells and platelet counts (p>0.05). Also, no significant differences in thrombotic event incidence were found between patient categories defined on the basis of cut-off values for white blood cells (cut-off values of 15×103/mm3 and 8.7×103/mm3) and platelets (cut-off values of 1500×103/mm3) (p>0.05).

CONCLUSION

Although our results are generally in line with the published data, some divergence from previous results has been observed with respect to risk factors for thrombotic events. Absence of a correlation between leukocytosis and thrombosis may be related with the significant decline in white blood cells after treatment. Also, a significant reduction in platelet counts occurring in association with treatment is linked with a lowered incidence of thrombosis. Janus Kinase 2-positive patients had a similar thrombosis frequency with that reported in the literature.

Janus kinase 2 mutations in cases with BCR-ABL-negative chronic myeloproliferative disorders from Turkey

Objective:

We aimed to investigate the frequency of Janus kinase 2 (JAK2) mutations in cases with chronic myeloproliferative disorders (CMDs), and the relationship between the presence of JAK2 mutation and leukocytosis and splenomegaly, retrospectively.

Materials and Methods:

Patients, who were diagnosed with BCR-ABL-negative CMDs according to diagnosis criteria of the World Health Organization and followed up at the hematology clinic between 2013 and 2015, were investigated in terms of the frequency of JAK2 mutation in cases with CMDs, and the relationship between the presence of JAK2 mutation and leukocytosis and splenomegaly, retrospectively.

Results:

In total, 100 patients, who were diagnosed with BCR-ABL-negative CMDs, were evaluated retrospectively. The mean age of the patients with JAK2 positivity was significantly higher compared to patients with negative. JAK2-positivity rates in the age groups were significantly different. Gender, diagnosis, splenomegaly, and leukocytosis were not statistically different for JAK2 positivity between the groups.

Conclusion:

JAK2 V617F mutation is more commonly seen in older age as a risk for complications related to CDMS. Splenomegaly and leukocytosis are not associated with JAK2 V617F mutation.

Antithrombotic Management in Ischemic Stroke with Essential Thrombocythemia: Current Evidence and Dilemmas

Thrombotic diseases like ischemic stroke are common complications of essential thrombocythemia (ET) due to abnormal megakaryopoiesis and platelet dysfunction. Ischemic stroke in ET can occur as a result of both cerebral arterial and venous thrombosis. Management of ET is aimed at preventing vascular complications including thrombosis. Acute management of ischemic stroke in ET is the same as that in the general population without myeloproliferative disorders. However, an ET patient with ischemic stroke is at high risk for rethrombosis and is therefore additionally managed with cytoreductive therapy and antithrombotic agents. Given abnormal platelet production in ET, there is suboptimal suppression of platelets with the standard recommended dose of aspirin for cardiovascular (CV) prevention. Hence, for optimal CV protection in ET, low-dose aspirin is recommended twice daily in an arterial thrombotic disease like atherothrombotic ischemic stroke in presence of the following risk factors: age >60 years, Janus kinase2 V617F gene mutation, and presence of CV risk factors. In the presence of the same risk factors, concurrent antiplatelet and anticoagulant therapy is suggested for venous thrombosis. However, increased risk of bleeding with dual antithrombotic agents poses a significant challenge in their use in cerebral venous thromboembolism or atrial fibrillation in presence of the above-mentioned risk factors. We discuss these dilemmas regarding antithrombotic management in ischemic stroke in ET in this case-based review of literature in the light of current evidence.

Epidemiology, Pathogenesis, and Clinical Approach in Group 5 Pulmonary Hypertension

Pulmonary hypertension (PH) is recognized to be associated with a number of comorbid conditions. Based on these associations, PH is classified into 5 groups, considering common pathophysiologic drivers of disease, histopathologic features, clinical manifestations and course, and response to PH therapy. However, in some of these associated conditions, these characteristics are less well-understood. These include, among others, conditions commonly encountered in clinical practice such as sarcoidosis, sickle cell disease, myeloproliferative disorders, and chronic kidney disease/end stage renal disease. PH in these contexts presents a significant challenge to clinicians with respect to disease management. The most recent updated clinical classification schemata from the 6th World Symposium on PH classifies such entities in Group 5, highlighting the often unclear and/or multifactorial nature of PH. An in-depth review of the state of the science of Group 5 PH with respect to epidemiology, pathogenesis, and management is provided. Where applicable, future directions with respect to research needed to enhance understanding of the clinical course of these entities is also discussed.

Myeloproliferative neoplasms and pregnancy: Overview and practice recommendations

Pregnancy in the context of myeloproliferative neoplasms (MPN) poses unique fetal and maternal challenges. Current literature in this regard mostly involves essential thrombocythemia (ET) and less so polycythemia vera (PV) or myelofibrosis. In ET, live birth rate is estimated at 70% with first trimester fetal loss (˜ 30%) as the major complication. Risk of pregnancy-associated complications is higher in PV, thus mandating a more aggressive treatment approach. Herein, we appraise the relevant literature, share our own experience and propose management recommendations. Aspirin therapy may offer protection against fetal loss; however the additive benefit of systemic anticoagulation or cytoreductive therapy, in the absence of high risk disease, is unclear. We recommend cytoreductive therapy in the form of interferon alpha in all high risk and select low-risk ET and PV patients with history of recurrent fetal loss, prominent splenomegaly or suboptimal hematocrit control with phlebotomy. In addition, all women with PV should maintain strict hematocrit control <45% with the aid of phlebotomy. Systemic anticoagulation with low molecular weight heparin is advised in patients with history of venous thrombosis. Further clarification awaits prospective clinical trials that implement risk adapted therapeutic interventions.

Persistent leukocytosis in polycythemia vera is associated with disease evolution but not thrombosis

There are unresolved questions regarding the association between persistent leukocytosis and risk of thrombosis and disease evolution in polycythemia vera (PV), as much of the published literature on the topic does not appropriately use repeated-measures data or time-dependent modeling to answer these questions. To address this knowledge gap, we analyzed a retrospective database of 520 PV patients seen at 10 academic institutions across the United States. Taking hematologic laboratory data at ∼3-month intervals (or as available) for all patients for duration of follow-up, we used group-based trajectory modeling to identify latent clusters of patients who follow distinct trajectories with regard to their leukocyte, hematocrit, and platelet counts over time. We then tested the association between trajectory membership and hazard of 2 major outcomes: thrombosis and disease evolution to myelofibrosis, myelodysplastic syndrome, or acute myeloid leukemia. Controlling for relevant covariates, we found that persistently elevated leukocyte trajectories were not associated with the hazard of a thrombotic event (P = .4163), but were significantly associated with increased hazard of disease evolution in an ascending stepwise manner (overall P = .0002). In addition, we found that neither hematocrit nor platelet count was significantly associated with the hazard of thrombosis or disease evolution.

A Young Woman with Thrombocytosis

The diagnostic approach to thrombocytosis involves consideration of reactive, hereditary, and neoplastic causes. Once reactive causes of thrombocytosis, such as iron deficiency, infections, solid tumors, and other obvious causes such as post-splenectomy thrombocytosis, have been ruled out, the focus shifts to myeloid malignancies, such as chronic myeloid leukemia (CML), the classic Philadelphia chromosome-negative (Ph^-) myeloproliferative neoplasms (MPNs), essential thrombocythemia (ET), primary myelofibrosis (PMF), polycythemia vera (PV), myelodysplastic syndrome (MDS) with isolated deletion 5q and the rare MDS/MPN "overlap" syndrome, MDS/MPN with ring sideroblasts, and thrombocytosis (MDS/MPN-RS-T).

Leukocytosis and thrombosis in essential thrombocythemia and polycythemia vera: a systematic review and meta-analysis

In the last years, a growing amount of evidence has been produced regarding the role of leukocytosis as a risk factor for thrombosis in patients with myeloproliferative neoplasms, predominantly in polycythemia vera (PV) and essential thrombocythemia (ET). Results from epidemiologic studies on this issue, however, are inconclusive. We conducted a systematic review and meta-analysis of articles published in the last 12 years addressing the issue, according to a predefined protocol. Forty-one articles analyzing >30 000 patients met our inclusion criteria and were deemed of acceptable methodologic quality. In addition to data on thrombosis, data were collected on bleeding, hematologic evolution, secondary cancer, and death. The relative risk (RR) of thrombosis in the presence of leukocytosis was 1.59 (95% CI, 1.40-1.80), mainly accounted for by ET (RR, 1.65; 95% CI, 1.43-1.91) and arterial thrombosis (RR, 1.45; 95% CI, 1.13-1.86) subgroups; the effect was not significant in venous thrombosis alone. Sensitivity analyses considering recurrent events as well as white blood cell estimates adjusted or unadjusted for confounding factors confirmed the primary results. In addition, the pooled RR of studies that tested white blood cell counts in time-dependent models suggested a causative effect of leukocytes in the mechanism that triggers thrombosis. The effect of leukocytosis on bleeding (RR, 1.87; 95% CI, 1.26-2.77) and death (RR, 1.89; 95% CI, 1.59-2.23) was confirmed, whereas conclusions on hematologic evolutions and solid tumors were uncertain. To confirm the accuracy of these results, an investigation on individual patient data in a large collective archive of homogeneous patients is warranted.

Principal Component Analysis on Recurrent Venous Thromboembolism

The rates of recurrent venous thromboembolism (RVTE) vary widely, and its causes still need to be elucidated. Statistical multivariate methods can be used to determine disease predictors and improve current methods for risk calculation. The objective of this study was to apply principal component analysis to a set of data containing clinical records of patients with previous venous thromboembolism and extract the main factors that predict recurrent thrombosis. Records of 39 factors including blood and lipid parameters, hereditary thrombophilia, antiphospholipid syndrome, clinical data regarding previous thrombosis and treatment, and Doppler ultrasound results were collected from 235 patients. The results showed that 13 principal components were associated with RVTE and that 18 of 39 factors are the important for the analysis. These factors include red blood cell, white blood cell, hematocrit, red cell distribution width, glucose, lipids, natural anticoagulant, creatinine, age, as well as first deep vein thrombosis data (distal/proximal, d-dimer, and time of anticoagulation). The results demonstrated that simple clinical parameters easy to be collected can be used to predict rates of recurrence and to develop new clinical decision support systems to predict the rates of RVTE.

Thrombophilic Risk of Factor V Leiden, Prothrombin G20210A, MTHFR, and Calreticulin Mutations in Essential Thrombocythemia Egyptian Patients

Objectives

Essential thrombocythemia (ET) is one of the myeloproliferative neoplasms characterized by a sustained elevation of platelet numbers with a tendency for thrombosis and hemorrhage. The aim of this work is to establish the relation between calreticulin, factor V Leiden, prothrombin G20210A, and MTHFR mutations in ET patients and the thrombotic risk of these patients.

Methods

This study was carried out on 120 ET patients and 40 apparently healthy individuals as a control group.

Results

There were increases in WBCs, PLT counts, PT, fibrinogen concentration factor V Leiden, and MTHFR mutation in ET patients as compared to the control group (P < 0.05). Also, there were increases in WBCs, PLT counts, and hematocrit value in thrombosed ET patients as compared to the nonthrombosed ones (P < 0.05). On the contrary, there was no significantly statistical difference in ET patients with JAK2 V617F positive mutation versus the JAK2 negative group (P > 0.05) and in patients with cardiovascular risk factors versus patients with noncardiovascular risk factors (P > 0.05). ET patients with factor V Leiden, prothrombin gene, and CALR mutations were more prone to thrombosis (odds ratio 5.6, 5.7 and 4.7, respectively). On the contrary, JAk2V 617F and MTHFR mutations have no effect on the thrombotic state of those patients.

Conclusion

There is a significant increase risk of thrombosis in ET patients with CALR mutation, thrombophilic mutations, as well as factor V Leiden and prothrombin gene mutation with a risk of developing leukemic transformation.

Inhibitors of the blood coagulation process in patients with essential thrombocythemia

: The aim of the study was to assess the activity of protein C, protein S and tissue factor pathway inhibitor in relation to the risk factors for thrombotic complications in patients with essential thrombocythemia.The study group consisted of 45 newly diagnosed patients with essential thrombocythemia. Protein S activity was determined by chromogenic method. Activities of protein C and tissue factor pathway inhibitor (TFPI) were determined using ELISAs.Significantly lower protein C and protein S activity but higher TFPI activity were found in patients with ET in comparison with the control group. TFPI activity was higher in women as compared to men, and in patients over 60 years of age compared with patients below 60 years of age. TFPI activity was higher in patients with leukocytes count at least 11 g/l than in patients with leukocytes count below 11 g/l and the difference almost reached statistical significance. Significantly lower protein C activity was found in patients with the JAK2V617F mutation, in comparison with essential thrombocythemia patients JAK2V617F (-).The reduced protein C and protein S activity may be one of the pathogenic factors of increased prothrombotic state in essential thrombocythemia patients. The decreased protein C activity in patients with the JAK2 V617F mutation seems to confirm the significant role of this mutation in the pathogenesis of thrombotic complications in essential thrombocythemia patients. Significantly increased TFPI activity in essential thrombocythemia patients above 60 years of age and with leukocyte count above 11 g/l expresses the activation of the compensatory mechanism for increased prothrombotic activity.

The new WHO classification for essential thrombocythemia calls for revision of available evidences

In the 2016 revised classification of myeloproliferative neoplasms pre-fibrotic primary myelofibrosis (pre-PMF) was recognized as a separate entity, distinct from essential thrombocythemia (ET). Owing that the majority of cases falling in the pre-PMF category were previously diagnosed as ET, one may question about the need to re-evaluate the results of epidemiologic, clinical, and molecular studies, and the results of clinical trials in the two entities. Based on a critical review of recently published studies, pre-PMF usually presents with a distinct clinical and hematological presentation and higher frequency of constitutional symptoms. JAK2V617F and CALR mutations in pre-PMF patients are superimposable to ET, whereas non-driver high-risk mutations are enriched in pre-PMF compared with ET. Thrombosis is not significantly different, whereas bleeding is more frequent in pre-PMF. Median survival is significantly shorter in pre-PMF and 10-year cumulative rates progression to overt myelofibrosis is 0-1% vs. 10-12%, and leukemic transformation is 1-2% vs. 2-6%, in ET and pre-fibrotic-PMF, respectively. Most patients fall in the lower prognostic IPSS group in which observation alone can be recommended. Patients at intermediate risk may require a symptom-driven treatment for anemia, splenomegaly or constitutional symptoms while cytoreductive drugs are indicated in the high-risk category.

Data-driven analysis of JAK2V617F kinetics during interferon-alpha2 treatment of patients with polycythemia vera and related neoplasms

Treatment with PEGylated interferon-alpha2 (IFN) of patients with essential thrombocythemia and polycythemia vera induces major molecular remissions with a reduction in the JAK2V617F allele burden to undetectable levels in a subset of patients. A favorable response to IFN has been argued to depend upon the tumor burden, implying that institution of treatment with IFN should be as early as possible after the diagnosis. However, evidence for this statement is not available. We present a thorough analysis of unique serial JAK2V617F measurements in 66 IFN-treated patients and in 6 untreated patients. Without IFN treatment, the JAK2V617F allele burden increased exponentially with a period of doubling of 1.4 year. During monotherapy with IFN, the JAK2V617F allele burden decreased mono- or bi-exponentially for 33 responders of which 28 patients satisfied both descriptions. Bi-exponential description improved the fits in 19 cases being associated with late JAK2V617F responses. The decay of the JAK2V617F allele burden during IFN treatment was estimated to have half-lives of 1.6 year for the monoexponential response and 1.0 year in the long term for the bi-exponential response. In conclusion, through data-driven analysis of the JAK2V617F allele burden, we provide novel information regarding the JAK2V617F kinetics during IFN-treatment, arguing for early intervention.

Clonal hematopoiesis, aging, and cardiovascular diseases

Cardiovascular diseases (CVDs) remain the leading cause of death worldwide. Many studies have provided evidence that both genetic and environmental factors induce atherosclerosis, leading thus to cardiovascular complications. Atherosclerosis is an inflammatory disease, and aging is strongly associated with the development of atherosclerosis. Recent experimental evidence suggests that clonal hematopoiesis (CH) is an emerging cardiovascular risk factor that contributes to the development of atherosclerosis and cardiac dysfunction and exacerbates cardiovascular diseases. CH is caused by somatic mutations in recurrent genes in hematopoietic stem cells, leading to the clonal expansion of mutated blood cell clones. Many of the mutated genes are known in the context of myeloid neoplasms. However, only some individuals carrying CH mutations develop hematologic abnormalities. CH is clearly age dependent and is not rare: at least 10%-20% of people >70 years old carry CH. The newly discovered association between myeloid leukemia-driver mutations and the progression of CVDs has raised medical interest. In this review, we summarize the current view on the contribution of CH in different cardiovascular diseases, CVD risk assessment, patient stratification, and the development of novel therapeutic strategies.

Interleukin4Rα (IL4Rα) and IL13Rα1 Are Associated with the Progress of Renal Cell Carcinoma through Janus Kinase 2 (JAK2)/Forkhead Box O3 (FOXO3) Pathways

Specific kinds of interleukin (IL) receptors are known to mediate lymphocyte proliferation and survival. However, recent reports have suggested that the high expression of IL4Rα and IL13Rα1 in tumor tissue might be associated with tumorigenesis in several kinds of tumor. We found that a significant association between mRNA level of IL4Rα or IL13Rα1 and the poor prognosis of renal cell carcinoma (RCC) from the public database (http://www.oncolnc.org/). Then, we evaluated the clinicopathological significance of the immunohistochemical expression of IL4Rα and IL13Rα1 in 199 clear cell RCC (CCRCC) patients. The individual and co-expression patterns of IL4Rα and IL13Rα1 were significantly associated with cancer-specific survival (CSS) and relapse-free survival (RFS) in univariate analysis. Multivariate analysis indicated IL4Rα-positivity and co-expression of IL4Rα and IL13Rα1 as the independent indicators of shorter CSS and RFS of CCRCC patients. For the in vitro evaluation of the oncogenic role of IL4Rα and IL13Rα1 in RCC, we knock-downed IL4Rα or IL13Rα1 and observed that the cell proliferation rate was decreased, and the apoptosis rate was increased in A498 and ACHN cells. Furthermore, we examined the possible role of Janus kinase 2 (JAK2), well-known down-stream tyrosine kinase under the heterodimeric receptor complex of IL4Rα and IL13Rα1. Interestingly, JAK2 interacted with Forkhead box O3 (FOXO3) to cause tyrosine-phosphorylation of FOXO3. Silencing IL4Rα or JAK2 in A498 and ACHN cells reduced the interaction between JAK2 and FOXO3. Moreover, pharmacological inhibition of JAK2 induced the nuclear localization of FOXO3, leading to increase apoptosis and decrease cell proliferation rate in A498 and ACHN cells. Taken together, these results suggest that IL4Rα and IL13Rα1 might be involved in the progression of RCC through JAK2/FOXO3 pathway, and their expression might be used as the novel prognostic factor and therapeutic target for RCC patients.

JAK2 V617F -Mediated Clonal Hematopoiesis Accelerates Pathological Remodeling in Murine Heart Failure

Janus kinase 2 (valine to phenylalanine at residue 617) (JAK2 ^V617F ) mutations lead to myeloproliferative neoplasms associated with elevated myeloid, erythroid, and megakaryocytic cells. Alternatively these same mutations can lead to the condition of clonal hematopoiesis with no impact on blood cell counts. Here, a model of myeloid-restricted JAK2 ^V617F expression from lineage-negative bone marrow cells was developed and evaluated. This model displayed greater cardiac inflammation and dysfunction following permanent left anterior descending artery ligation and transverse aortic constriction. These data suggest that JAK2 ^V617F mutations arising in myeloid progenitor cells may contribute to cardiovascular disease by promoting the proinflammatory properties of circulating myeloid cells.

Myeloproliferative Neoplasms in Children and Adolescents and Thrombosis at Unusual Sites: The Role of Driver Mutations

Myeloproliferative neoplasms (MPNs) in childhood and adolescence are rare and seldom complicated by thrombosis. We describe 3 cases of thrombosis at unusual sites in young patients with MPNs. In the pediatric MPN population, unlike in adult MPNs, a clonal mutation is identifiable in only a minority of cases (22% to 26%). All 3 of these individuals had JAK2 mutations driving the disease process. A literature search identified 19 cases of MPN-associated thrombosis in children. Seventeen of the 19 children (89.5%) had a driver mutation. These cases suggest that identifiable driver mutations may confer an increased thrombotic risk in children with MPNs.

[Clinical features and diagnosis of Ph - negative myeloproliferative neoplasms occurring in conjunction with the antiphospholipid syndrome]

Thrombosis is a serious and extremely dangerous disease that has a negative impact on the quality and longevity. Antiphospholipid syndrome (APS) is a pathology characterized by recurring venous, arterial, microvasculature thrombosis, pregnancy pathology with loss of the fetus and the synthesis of antiphospholipid antibodies. A high risk of thrombotic complications is also observed in patients with myeloproliferative neoplasms (MPN). This article presents a description of three clinical cases of Ph - negative myeloproliferative diseases, occurring in conjunction with APS. In all cases, recurrent thrombosis allowed to suspect the presence of two diseases - MPN and APS.

A systematic review and meta-analysis of the prevalence of thrombosis and bleeding at diagnosis of Philadelphia-negative myeloproliferative neoplasms

BACKGROUND

Philadelphia (Ph) chromosome-negative myeloproliferative neoplasms (MPNs) are a heterogeneous group of hematopoietic stem cell clonal diseases. Most patients with MPN are asymptomatic at diagnosis although some of them suffer from constitutional symptoms. Thrombosis and bleeding can also be one of the initial manifestations although the reported prevalence varied considerably across the studies. This systematic review and meta-analysis was conducted with the aims to better understand the prevalence and characteristics of thrombosis and bleeding among patients with newly-diagnosed MPN.

METHODS

Using a search strategy that included the terms for myeloproliferative neoplasms, thrombosis, and bleeding, two investigators independently searched for published articles indexed in the MEDLINE and EMBASE databases from inception to August 2018. The pooled prevalence was calculated using the DerSimonian-Laird random-effects model with a double arcsine transformation.

RESULTS

A total of 29 cohort studies (8 prospective and 21 retrospective) with 13,436 patients with MPN were included into this meta-analysis. At diagnosis, the pooled prevalence of overall thrombosis among patients with MPN was 20.0% (95% CI, 16.6-23.8%; I² 96%), with the pooled prevalence of arterial thrombosis of 16.2% (95% CI, 13.0-20.0%; I² 95%) and the pooled prevalence of venous thrombosis of 6.2% (95% CI, 4.9-7.8%; I² 89%). Common thrombotic events included cerebrovascular disease/transient ischemic attack, coronary heart disease, and deep venous thrombosis. The pooled prevalence of hemorrhagic complications among patients who were newly diagnosed with MPN patients was 6.2% (95% CI, 5.0-7.8%; I² 85%). Common sites of bleeding included gastrointestinal, mucosal, and cutaneous bleeding.

CONCLUSIONS

Thrombosis and bleeding are common initial manifestations of MPN. Investigations for MPN should be considered for patients who present with unexplained thrombosis or abnormal bleeding.

Activation of TF-Dependent Blood Coagulation Pathway and VEGF-A in Patients with Essential Thrombocythemia

Background and objectives: Recent studies suggest that a vascular endothelial growth factor (VEGF-A) may be involved in the thrombotic process by stimulating the expression of tissue factor in vascular endothelial cells. Tissue factor (TF) can also stimulate the transcription of the gene encoding VEGF-A. The relationship between coagulation and angiogenesis in myeloproliferative neoplasms is not fully understood. The aim of this study was to evaluate the concentration of TF in relation to VEGF-A in the blood of patients with essential thrombocythemia (ET). Patients and methods: The study group consisted of 130, newly diagnosed patients with ET (mean age 61 years). The control group consisted of 35 healthy volunteers (mean age 51 years). Concentrations of VEGF-A, TF, and tissue factor pathway inhibitor (TFPI) were analysed using immunoenzymatic methods. TF and TFPI activities were performed using chromogenic assays. Results: The median concentration of TF Ag was 3-fold higher and the TF activity was more than 15-fold higher in ET patients than in normal individuals. There were no statistically significant differences in the TFPI concentration and activity between groups. VEGF-A was significantly increased in patients with ET (p < 0.000001). Analysis of correlations revealed a positive correlation between VEGF-A and TF Ag as well as a positive correlation between VEGF-A and TFPI activity. Conclusions: The simultaneous increase of TF concentration and activity, VEGF-A in the blood of patients with ET, as well as a positive correlation between the concentration of TF and VEGF-A demonstrates the coexistence of TF-dependent coagulation and activation of angiogenesis.

A Rare Case of Triple-Negative Essential Thrombocythemia in a Young Postsplenectomy Patient: A Diagnostic Challenge

The distinction between primary and reactive thrombocytosis by bone marrow histology is very important. Reactive thrombocytosis, the most common cause of thrombocytosis, can be expected in postsplenectomy states; however, close hematological evaluation of prolonged thrombocytosis is essential to identify patients who may have an underlying myeloproliferative neoplasm. We report a 37-year-old woman who was found to have portal, mesenteric, and splenic vein thrombosis with thrombocytosis, two months after she had a splenectomy for spontaneous splenic rupture. Other reactive conditions and myeloproliferative neoplasms (MPN) were excluded, and subsequently, the diagnosis of triple-negative essential thrombocythemia (ET) was established by bone marrow histology. This case of primary thrombocythemia following splenectomy in a young patient illustrates some of the diagnostic difficulties associated with postsplenectomy thrombocytosis. Continuing reports of anecdotal experiences in managing similar complex scenarios is essential and remains the only reference for clinicians facing these rare conditions.

Clonal hematopoiesis: Genes and underlying mechanisms in cardiovascular disease development

The clonal hematopoiesis when occurring without hematologic abnormalities is defined as clonal hematopoiesis of indeterminate potential (CHIP). Aging causes accumulation of somatic mutations, and hematopoietic stem cells (HSCs) can develop clonal expansion of different lineages by these mutations. CHIP has a correlation with cancer and cardiovascular disease (CVD) through acquired mutations in genes. DNMT3A, TET2, ASXL1, and JAK2 genes as well as other genes are the most common somatic mutations causing CHIP and CVD in an older age. Other factors such as cholesterol level, laboratory tests and indexes also affect CVD. In addition, mutations in adenosine triphosphate-binding cassette transporters and also chronic stress in nervous system can result in HSCs proliferation and CVD. However, laboratory tests and indexes are not sensitive for CVD diagnosis. But the therapeutic interventions can be helpful to prevent CVD cases by targeting somatic mutations, chemokine receptors, and growth factors in HSCs. Also, new drugs can control CVD by targeting of cells and their signaling pathways in HSCs. Therefore, more investigations are needed and more questions should be answered for the relationship between CHIP and CVD as a challenging issue in future.

Assessment of Endothelial Dysfunction With Flow-Mediated Dilatation in Myeloproliferative Disorders

BACKGROUND

Thrombosis is the most important cardiovascular complication of classical myeloproliferative disorders (MPDs). Endothelial dysfunction (ED) is known to play a major role in the mechanism of thrombophilia in MPDs.

METHODS

Endothelial dysfunction and its associations with other parameters were investigated. A total of 18 patients with polycythemia vera (PV), 24 with essential thrombocytosis (ET), 7 with primary myelofibrosis (PMF), and 30 healthy patients as a control group were included in the study. To assess the ED, flow-mediated dilatation (FMD) measurements were used.

RESULTS

The FMD (%) result showing ED was determined as 9.9 (0.0-21.6) in the patients with PV, 7.3 (0.0-30.5) in patients with ET, 7.5 (0.0-18.0) in patients with PMF, and 13.9 (6.2-26.7) in the control group. The FMD (%) was markedly impaired in all patients with MPD compared to the control patients (7.8 [0.0-30.5] vs 13.9 [6.15-26.8], P = .02). According to the disease subtypes, FMD (%) was significantly lower in the ET group than in the control group ( P = .01).

CONCLUSION

Endothelial function was assessed in patients with MPD having FMD and was determined to demonstrate ED. Lower FMD was associated with older age, leukocytosis, thrombocytosis, and thrombosis history.

Influence of Blood Count, Cardiovascular Risks, Inherited Thrombophilia, and JAK2 V617F Burden Allele on Type of Thrombosis in Patients With Philadelphia Chromosome Negative Myeloproliferative Neoplasms

INTRODUCTION

Thrombosis is the most common complication in Philadelphia chromosome negative (Ph-) myeloproliferative neoplasms patients.

PATIENTS AND METHODS

In a cohort of 258 Ph- myeloproliferative neoplasm patients, the difference between patients with and without thrombosis was analyzed according to genetic thrombophilia factors, JAK2 V617F status and burden allele, blood count, cardiovascular risk factors and age. Patients were also divided in polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) subgroups as well as by the type of thrombosis.

RESULTS

Analysis of cardiovascular risk factors regarding arterial thrombosis showed that PV patients with thrombosis had higher incidence of diabetes (P = .030), ET patients more often had hypertension (P = .003) and hyperlipidemia (P = .005), while PMF patients had hyperlipidemia (P = .046) and at least one cardiovascular risk factor (P = .044). Moreover, leukocytes > 18 × 10⁹/L and V617F burden allele > 25.7% were statistically significantly different in PV patients (P = .019 and borderline significant at P = .055, respectively), while in ET patients leukocytes > 9.2 × 10⁹/L (P < .001) and age at diagnosis of > 55 years were statistically significantly different (P = .002). PMF patients with V617F burden allele ≤ 34.8% were more prone to thrombosis (P = .032). When comparing patients with and without venous thrombosis, cutoff value of V617F burden allele > 90.4% was significant for PV patients with thrombosis (P = .036), as was > 56.7% for PMF patients with thrombosis (P = .046). Platelets ≤ 536 × 10⁹/L and age at diagnosis > 54 years showed statistically significant difference for ET patients with thrombosis (P = .015 and P = .041, respectively).

CONCLUSION

On the basis of our results, a new scoring system for thrombosis risk in PV could be made, while PMF prognostic model may be expanded for better recognition of potential thrombotic risk factors.

Recommendations for the diagnosis and treatment of patients with polycythaemia vera

OBJECTIVES

To present the Central European Myeloproliferative Neoplasm Organisation (CEMPO) treatment recommendations for polycythaemia vera (PV).

METHODS

During meetings held from 2015 through 2017, CEMPO discussed PV and its treatment and recent data.

RESULTS

PV is associated with increased risks of thrombosis/thrombo-haemorrhagic complications, fibrotic progression and leukaemic transformation. Presence of Janus kinase (JAK)-2 gene mutations is a diagnostic marker and standard diagnostic criterion. World Health Organization 2016 diagnostic criteria for PV, focusing on haemoglobin levels and bone marrow morphology, are mandatory. PV therapy aims at managing long-term risks of vascular complications and progression towards transformation to acute myeloid leukaemia and myelodysplastic syndrome. Risk stratification for thrombotic complications guides therapeutic decisions. Low-risk patients are treated first line with low-dose aspirin and phlebotomy. Cytoreduction is considered for low-risk (phlebotomy intolerance, severe/progressive symptoms, cardiovascular risk factors) and high-risk patients. Hydroxyurea is suspected of leukaemogenic potential. IFN-α has demonstrated efficacy in many clinical trials; its pegylated form is best tolerated, enabling less frequent administration than standard interferon. Ropeginterferon alfa-2b has been shown to be more efficacious than hydroxyurea. JAK1/JAK2 inhibitor ruxolitinib is approved for hydroxyurea resistant/intolerant patients.

CONCLUSIONS

Greater understanding of PV is serving as a platform for new therapy development and treatment response predictors.

Luteinizing hormone signaling restricts hematopoietic stem cell expansion during puberty

The number and self-renewal capacity of hematopoietic stem cells (HSCs) are tightly regulated at different developmental stages. Many pathways have been implicated in regulating HSC development in cell autonomous manners; however, it remains unclear how HSCs sense and integrate developmental cues. In this study, we identified an extrinsic mechanism by which HSC number and functions are regulated during mouse puberty. We found that the HSC number in postnatal bone marrow reached homeostasis at 4 weeks after birth. Luteinizing hormone, but not downstream sex hormones, was involved in regulating HSC homeostasis during this period. Expression of luteinizing hormone receptor (Lhcgr) is highly restricted in HSCs and multipotent progenitor cells in the hematopoietic hierarchy. When Lhcgr was deleted, HSCs continued to expand even after 4 weeks after birth, leading to abnormally elevated hematopoiesis and leukocytosis. In a murine acute myeloid leukemia model, leukemia development was significantly accelerated upon Lhcgr deletion. Together, our work reveals an extrinsic counting mechanism that restricts HSC expansion during development and is physiologically important for maintaining normal hematopoiesis and inhibiting leukemogenesis.

Association of JAK2V617F mutation with thrombosis in Indian patients with Philadelphia negative chronic myeloproliferative neoplasms

Background

: It is still a matter of debate regarding the association of JAK2V617F mutation with thrombosis in BCR-ABL negative CMPN patients. The role of JAK2V617F mutation in increasing the thrombotic risk in CMPNs is yet unequivocal.

Aims

: To clarify the contribution of JAK2V617F mutation in thrombosis in CMPN patients.

Settings and Design

This retrospective study was done to evaluate role of JAK2V617F mutation in thrombosis in CMPNs.

Materials and Methods

65 CMPN patients (PV, ET and PMF) were analyzed for JAK2V617F mutation using ARMS-PCR and detailed history of thrombosis was recorded in these patients.

Statistical Analysis

P values were 2 tailed, and statistical significance was set at P < 0.05.

Results

: 46/65 were males and 19/65 were females [M: F: 2.4:1] with median age 46 years [range, 14-80 years]. Patients had median Hb 15.6 g/dl [range, 5.1-20.3], median TLC 10.7 × 10⁹/l [range 2.4-216] and platelet count 360 × 10⁹/l [range, 20-1859]. 32 were JAK2V617F positive and 33 were negative for this mutation. On comparing the prevalence of thrombosis in JAK2V617F positive patients with JAK2V617F negative patients, we observed that 20/32 (62.5%) JAK2V617F positive patients had thrombosis as compared to 16/33 (48%) in JAK2V617F negative patients (P = 0.04). We observed significant association of JAK2V617F mutation with thrombosis, however no association of this mutation with thrombosis was observed among the JAK2V617F negative patients.

Conclusion

Our study suggests that JAK2V617F mutation may increase the risk of thrombosis in CMPNs. This finding could lead to risk stratification, setting up the treatment strategy in CMPNs.

A spotlight on the management of complications associated with myeloproliferative neoplasms: a clinician's perspective

INTRODUCTION

Myeloproliferative neoplasms (MPNs) are associated with a variety of symptoms and signs which cause major morbidity for the patients. The disorders are associated with increased incidence of thromboembolic and hemorrhagic events which can lead to complications and shortened life expectancy. Areas covered: Using systematic literature review and expert clinical and research experience the authors discuss strategies for the management of symptoms and signs including pruritus, fatigue, splenomegaly, and cytopenia. Cytoreduction including treatments to inhibit the JAK/STAT pathway are considered. Pathogenesis and prevention and treatment of thrombotic and hemorrhagic events and their management is addressed and the suggested management of the special situations such as surgery and pregnancy are discussed. Expert commentary: Management of disease has traditionally focused on symptom treatment and complication prevention but the discovery of driver mutations has led to treatments aiming to eliminate the clone, which should be the ultimate goal of therapy. A future challenge is to develop safe and effective MPN therapy and to personalize therapy.

Clonal Hematopoiesis and Risk of Atherosclerotic Cardiovascular Disease

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP), which is defined as the presence of an expanded somatic blood-cell clone in persons without other hematologic abnormalities, is common among older persons and is associated with an increased risk of hematologic cancer. We previously found preliminary evidence for an association between CHIP and atherosclerotic cardiovascular disease, but the nature of this association was unclear.

METHODS

We used whole-exome sequencing to detect the presence of CHIP in peripheral-blood cells and associated such presence with coronary heart disease using samples from four case-control studies that together enrolled 4726 participants with coronary heart disease and 3529 controls. To assess causality, we perturbed the function of Tet2, the second most commonly mutated gene linked to clonal hematopoiesis, in the hematopoietic cells of atherosclerosis-prone mice.

RESULTS

In nested case-control analyses from two prospective cohorts, carriers of CHIP had a risk of coronary heart disease that was 1.9 times as great as in noncarriers (95% confidence interval [CI], 1.4 to 2.7). In two retrospective case-control cohorts for the evaluation of early-onset myocardial infarction, participants with CHIP had a risk of myocardial infarction that was 4.0 times as great as in noncarriers (95% CI, 2.4 to 6.7). Mutations in DNMT3A, TET2, ASXL1, and JAK2 were each individually associated with coronary heart disease. CHIP carriers with these mutations also had increased coronary-artery calcification, a marker of coronary atherosclerosis burden. Hypercholesterolemia-prone mice that were engrafted with bone marrow obtained from homozygous or heterozygous Tet2 knockout mice had larger atherosclerotic lesions in the aortic root and aorta than did mice that had received control bone marrow. Analyses of macrophages from Tet2 knockout mice showed elevated expression of several chemokine and cytokine genes that contribute to atherosclerosis.

CONCLUSIONS

The presence of CHIP in peripheral-blood cells was associated with nearly a doubling in the risk of coronary heart disease in humans and with accelerated atherosclerosis in mice. (Funded by the National Institutes of Health and others.).

The Impact of Mean Platelet Volume (MPV) and JAK-2 Mutation on Thrombosis in Chronic Myeloproliferative Diseases

Thrombosis and bleeding are the main complications of chronic myeloproliferative diseases. Mean platelet volume (MPV) is an important indicator of the platelet activation. The aim of the present study was to assess the interrelationships between MPV, JAK-2 gene mutation and thromboembolic events in patients with ET and PV. Patients with ET (n = 60) and PV (n = 46) were compared to the secondary erythrocytosis group (n = 19); and a control group of age and sex matched healthy volunteers (n = 52). Besides demographic, clinical and laboratory data; thrombotic and hemorrhagic events were recorded for each patient. Platelet counts, MPV and JAK2 mutations were studied; and their relation with thromboembolic events were investigated using SPSS program for statistical analysis. There was no significant difference between groups regarding age (p = 0.188). Mean platelet count was significantly higher in ET group than other groups (p < 0.0001). Mean platelet count in PV group was significantly higher than control (p < 0.0001) and secondary erythrocytosis groups (p < 0.0001). In the ET group, MPV values were significantly lower than the control group and PV group. In the ET group, those with thromboembolia had lower platelet counts. There was no relation between MPV and thromboembolic event rate in PV, ET and secondary erithrocytosis groups; while no event was recorded in the control group. There was no relation between thromboembolic event rate and JAK 2 mutation. The association of JAK-2 mutation and high MPV especially in ET and PV groups does not contribute to the thromboembolic events.

Comparison of JAK2V617F -positive essential thrombocythaemia and early primary myelofibrosis: The impact of mutation burden and histology

An accurate histological diagnosis may distinguish essential thrombocythaemia (ET) from early primary myelofibrosis (early-PMF), which is associated with worse outcome. Outcome of ET is also negatively affected by the presence of the JAK2^V617F mutation. To investigate the impact of JAK2^V617F mutation burden and histology on outcome, we collected 475 WHO-diagnosed ET (69.2%) or early-PMF JAK2^V617F -positive patients followed in 4 Italian haematology centers. JAK2^V617F allele burden was ≤50% in 90% and 87% of ET and early-PMF patients, respectively (P = .34). During follow-up, 32 (9.7%) ET and 18 (12.3%) early-PMF patients experienced 59 thrombotic events, and 27 patients (5.6%) and 6 (1.2%) patients evolved to myelofibrosis and acute leukemia, respectively. At last contact, 28 (5.8%) patients had died. In early-PMF compared to ET, the 10-year mortality rates (6.7% and 4.3%, P = .73), leukemic transformation rates (1.4% and 1.2%, P = .45), and thrombosis rates (16.7% and 12.2%, P = .12) were comparable. Only progression to overt myelofibrosis at 10 years was significantly worse (11.4% and 1.5%, P = .004). In multivariate analysis, a higher (>50%) JAK2^V617F burden was significantly correlated with fibrotic progression and histology. Considering JAK2^V617F -positive disease, a higher (>50%) JAK2^V617F burden and histological classification are independent prognostic risk factors for disease progression. These findings reinforce the need for standardized detection of this mutation.

Persistent neutrophilia is a marker for an increased risk of venous thrombosis

In patients with cancer and myeloproliferative disorders, leukocytosis has been associated with an increased venous thromboembolic (VTE) risk. Our goal was to determine whether persistent neutrophilia (PN), not associated with known causes such as malignancies, infections or steroids, is independently associated with VTE. All adult patients with >3 outpatient complete blood counts (CBCs) within 3 years were included. PN was defined as having an absolute neutrophil count >95 % (>2SD) of the population (≥7.8 × 10(9)/L) on at least three CBCs, at least 2 months apart. Separate analyses for neutrophil counts ≥9 × 10(9)/L and ≥10 × 10(9)/L were also performed. Blood counts from inpatients were excluded. Primary outcome was diagnosis of VTE, as determined by ICD-9 codes. Odds ratios were adjusted for diabetes, smoking, obesity, gender, and age. Charlson score was utilized as a morbidity measure. Data on 43,538 outpatients were collected. Although there was no association of VTE with neutrophil counts ≥7.8 × 10(9)/L, patients with ≥9.0 × 10(9)/L neutrophils were twice as likely to be diagnosed with VTE compared to those with normal neutrophil counts (OR 2.0, 95 % CI 1.3, 3.1; p = 0.003). Patients with neutrophil counts ≥10.0 × 10(9)/L were at an even higher risk (OR 2.3, 95 % CI 1.2, 4.8; p = 0.019). Charlson scores significantly modified this risk when incorporated into analysis. Elevated neutrophil counts are associated with an increased risk of venous thrombosis even when they are not due to cancer, infection or steroids. In patients with significant comorbidities, neutrophilia may be a marker of VTE risk.