Thrombosis and haemorrhage in polycythaemia vera and essential thrombocythaemia

[Thrombosis and platelet dysfunction in myeloproliferative neoplasms]

Myeloproliferative neoplasms are acquired hematological malignancies, mainly affecting the adult and whose morbidity and mortality stems from haemostasis disorders. The most frequently encountered complications include thrombosis, affecting preferentially the arterial territory, but also atypical locations such as splanchnic vein thrombosis. The pathophysiology of these thromboses is complex and involves different actors: blood cells, endothelium and flow conditions. Numerous studies have been conducted to identify risk factors for thrombosis. To date, only two risk factors have been validated through prospective studies (age over 60 years old, history of thrombotic events) and allow classification of patients as "low risk" and "high risk" as the basis for current treatment recommendations. Haemorrhagic manifestations, less frequent than thrombosis, are mainly related to an alteration of primary haemostasis and are therefore manifested by mucocutaneous bleeding. In these patients, platelet dysfunctions and/or acquired Willebrand syndromes can be found. The pathophysiology of thrombosis and platelet dysfunction during myeloproliferative neoplasms remains to date partially unknown. In this review, we offer to focus on physiopathological mechanisms as well as the latest advances in their understanding.

Recommendations for Therapeutic Apheresis by the Section "Preparative and Therapeutic Hemapheresis" of the German Society for Transfusion Medicine and Immunohematology

The section "Preparative and Therapeutic Hemapheresis" of the German Society for Transfusion Medicine and Immunohematology (DGTI) has reviewed the actual literature and updated techniques and indications for evidence-based use of therapeutic apheresis in human disease. The recommendations are mostly in line with the "Guidelines on the Use of Therapeutic Apheresis in Clinical Practice" published by the Writing Committee of the American Society for Apheresis (ASFA) and have been conducted by experts from the DACH (Germany, Austria, Switzerland) region.

A prothrombotic state and denser clot formation in patients following acute limb ischemia of unknown cause

INTRODUCTION

Fibrin clot structure differs between healthy individuals and those following thromboembolic events. Dense and poorly lysable fibrin clots have also been reported in peripheral artery disease. We studied fibrin clot properties and its determinants in individuals with a history of acute lower limb ischemia (ALI) of unknown cause.

MATERIALS AND METHODS

In this case-control study, we enrolled 43 patients who experienced ALI of unknown cause, and two age-and sex-matched reference groups: (1) patients with cryptogenic non-lacunar stroke (n = 43) and (2) individuals without any history of thromboembolism (n = 43, control group). Plasma fibrin clot properties, along with thrombin generation and fibrinolysis markers were assessed following ≥3 months of anticoagulation.

RESULTS

Compared with the control group, the ALI group exhibited more compact plasma fibrin clots (13.4% lower permeability [K_s], p = .001), decreased formed clot lysis (12.5% lower D-D_rate, p = .001) and unaltered clot lysis potential, along with enhanced thrombin generation potential (49% higher peak thrombin concentration, p < .0001). There were no differences in these variables between ALI and stroke patients. Patients with ALI had slightly higher α₂-antiplasmin and lower plasminogen activator inhibitor 1 levels compared with the stroke and control groups (all p < .01).

CONCLUSIONS

Patients who experienced ALI of unknown cause display a prothrombotic fibrin clot phenotype, including increased clot density and hypofibrinolysis associated with higher thrombin generation, which might suggest potential benefits from prolonged anticoagulation in this disease.

A Rare Cause of Gastrointestinal Bleeding in a 65-Year-Old Man with History of Polycythemia Vera

Polycythemia vera (PV) is classified as a myeloproliferative disorder (MPD). Such patients are prone to both thrombotic and hemorrhagic events. Although gastrointestinal (GI) bleeding is not a prominent manifestation of PV, it would be life threatening and necessitating hospital admission and blood transfusion if it occurs. GI hemorrhage in these patients may be due to Aspirin usage, peptic ulcer disease (PUD), acquired Von Willbrand disease, Dieulafoy lesion (DL), Mallory Weiss tear, and esophageal and gastric varices. DL is an enlarged, thick-walled artery in the muscularis mucosa with a small submucosal defect. In this case report, we describe a 65-year-old man with history of PV presented with a massive upper GI bleeding. After a therapeutic endoscopic hemostasis failure and reoccurrence of bleeding during hospital admission, an abdominal computed tomography (CT) was ordered, which revealed an aberrant artery originated from aorta directly into the stomach. An angiographic embolization was considered for the patient, which was successfully performed. Our patient was complicated by splenic infarction due to splenic collateral arteries embolization and the overwhelming thrombotic tendency of the patient himself due to the history of PV. Fortunately, our patient's signs and symptoms responded to supportive therapies and eventually he discharged well.

Acute multiple cerebral infarction combined with cerebral microhemorrhage in Polycythemia vera: A case report

Polycythemia vera (PV) is one of the rare causes of cerebrovascular disease, whose common manifestations in the nervous system are cerebral infarction and transient ischemic attack. A number of cases of PV patients with bleeding complicated with subdural hemorrhage or cerebral hemorrhage have been previously reported. However, sometimes PV patient with complicated cerebral hemorrhage and lower extremity venous thrombosis have been admitted to the People's Hospital of Liaoning Province. The present case study reports on a patient with acute multiple cerebral infarction with cerebral micro-hemorrhage associated with PV, who was not treated with anti-thrombosis treatment. After bloodletting treatment and hydroxyurea treatment, the patients condition was stable and they were discharged. A possible mechanism of infarction is that PV may cause abnormal proliferation of red blood cells, white blood cells and platelets in the circulation, resulting in an increase of blood viscosity and reduction of blood flow velocity. Platelet deficiency may cause abnormal blood coagulation function, which may be the reason for the blood and thrombotic diseases in patients with PV.

Bleeding Disorders Associated with Cancer

Cancer can be associated with several distinct coagulation defects which can lead to bleeding complications. The primary hyperfibrinolytic syndrome associated with acute promyelocytic leukemia has been well recognized and is one of the most severe bleeding disorders. Acquired hemophilia, while rare and not only seen in the oncology setting, can be triggered by a malignancy and must be promptly recognized in order to prevent catastrophic hemorrhage. Other, less serious coagulopathic states have been linked to cancer, including acquired von Willebrand disease. Finally, several anti-neoplastic drugs can alter hemostasis and increase the risk of bleeding. A good understanding of this field can help mitigate the risk of complications in the cancer patient.

Myeloproliferative Neoplasms: A Primer for Radiologists

The myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases including polycythemia vera, essential thrombocythemia, and primary myelofibrosis. Knowledge of the radiological and clinical features of MPNs and their associated complications is critical for interpreting radiologists. The purpose of this article is to provide a primer to radiologists summarizing the modern understanding of MPNs from an imaging-based perspective, including common disease-related findings and complications related to hematopoietic cell transplant.

Coexistence of Hermansky-Pudlak syndrome and JAK2V617F-positive essential thrombocythemia

Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder consisting of oculocutaneous albinism, platelet storage pool deficiency, and lysosomal accumulation of ceroid lipofuscin. The storage pool deficiency of HPS is associated with the lack of dense bodies in the platelets, resulting in impaired response in the secondary phase of aggregation. Patients with HPS have normal coagulation tests; however, their bleeding time is usually prolonged despite normal or increased platelet counts. Essential thrombocythemia (ET) is an uncommon condition, with an incidence of approximately 1.1 per 100,000/year, and it is the most common cause of primary thrombocytosis. JAK2^V617F positivity can be observed in approximately half of the patients with ET. Bleeding events in ET have usually been associated with acquired von Willebrand syndrome paradoxically occurring when the platelet counts are extremely high. We, herein, present a case with bleeding diathesis diagnosed as having both HPS and JAK2^V617F-positive ET.

Developments in diagnosis and treatment of essential thrombocythemia

INTRODUCTION

Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm characterized by thrombocytosis, increased risk of thrombotic/hemorrhagic events and clonal evolution into blast phase or myelofibrosis. Areas covered: The authors will discuss biology, diagnosis, prognosis, therapy, and outcome of ET. An accurate molecular-morphologic assessment is necessary in order to properly establish diagnosis and prognosis of ET. Stratification for thrombosis prediction is essential, and IPSET-t model is widely applied. The current treatment strategy is directed to lower the rate of vascular events using cytoreduction in patients at high risk. Prophylactic low dose aspirin indication is more uncertain. To date, therapies for patients who are resistant or intolerant to first-line treatments are scarce. Overall, life expectancy indicates an indolent disease, but IPSET model helps in predicting survival at the time of diagnosis. Expert opinion: Challenging for the future will be to share criteria for ET diagnosis with the community. New insights into the molecular pathogenesis of the disease will improve the prediction of clonal evolution and outcome, and lead to the use of disease-modifying treatments.

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.

Acute ST-segment Elevation Myocardial Infarction as the First Manifestation of Essential Thrombocytosis

A 36-year-old female with no significant past medical history presented with sudden onset of crushing substernal chest pain. When the emergency medical services (EMS) arrived, she had a cardiac arrest requiring defibrillation two times in the field prior to arriving at the hospital. In the emergency department (ED), the electrocardiogram (ECG) was significant for ST-elevation that suggested acute anterolateral infarct. Her laboratory evaluation also showed a platelet count of 1095 x 10³/ul. Also, her troponin levels were at 0.16 ng/ml at the time of arrival and peaked at 42.8 ng/ml. She immediately underwent a cardiac catheterization which showed 100% occlusion of her left anterior descending (LAD) artery by a thrombus, which was then treated with a thrombectomy and a single drug-eluting stent was placed. Upon further work-up of her thrombocytosis, the patient had a bone marrow biopsy showing megakaryocytic hyperplasia which no evidence of fibrosis. She was tested for Janus kinase 2 (JAK2) mutation which was positive. The patient was diagnosed with essential thrombocytosis (ET) and was started on cytoreduction therapy with hydroxyurea. Her platelet counts responded appropriately and dropped to less than 500 x 10³ at the time of discharge.

Prognostic value of JAK2V617F mutation in pseudotumor cerebri associated with cerebral venous sinus thrombosis

OBJECTIVES

To examine the clinical characteristics and prognosis of cerebral venous sinus thrombosis (CVST) that presented as pseudotumor cerebri (PTC) patients with JAK2V617F mutation.

METHODS

Medical records of all consecutive patients that presented with PTC and a JAK2V617F mutation who were treated were retrospectively reviewed. Data regarding demographics and ocular presenting symptoms and signs, neurological signs, hematological factors treatment, and prognosis were collected.

RESULTS

The most common presenting symptoms were headache (5 patients, 83.3%) and visual obscurations (5 patients, 83.3%). CVST of the sagittal sinus and sigmoid sinus were the most common site of thrombus. Platelet count and hemoglobin count were higher than normal during follow-up. There was significant change in the disk edema degree as well as decline in retinal nerve fiber layer (RNFL) thickness (P < 0.001, P < 0.001, Matched pairs). There was no significant change in visual acuity (VA) or mean deviation (MD) during follow-up (P = 0.95, 0.64, respectively, Matched pairs).

CONCLUSIONS

Pseudotumor cerebri resulting from CSVT in our patients with JAK2V617F mutation was frequent in young patients and needed medical and surgical treatment, without improvement in visual functions and in third caused poor visual outcome. Therefore, we believe that a screening test for JAK2V617F mutation should be considered for patients with CVST without known risk factor presenting with PTC, especially when sagittal sinus or sigmoid sinus involvement or thrombocytosis or high hemoglobin are found upon presentation. This might lead to more aggressive management which may improve the visual prognosis of those young patients.

Polycythemia vera and essential thrombocythemia: 2019 update on diagnosis, risk-stratification and management

Disease Overview: Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms respectively characterized by erythrocytosis and thrombocytosis; other disease features include leukocytosis, splenomegaly, thrombosis, bleeding, microcirculatory symptoms, pruritus, and risk of leukemic or fibrotic transformation. Diagnosis: Bone marrow morphology remains the cornerstone of diagnosis. In addition, the presence of JAK2 mutation is expected in PV while approximately 90% of patients with ET express mutually exclusive JAK2, CALR, or myeloproliferative leukemia mutations. In ET, it is most important to exclude the possibility of prefibrotic myelofibrosis. Survival: Median survivals are 14 years for PV and 20 years for ET; the corresponding values for younger patients are 24 and 33 years. Certain mutations (mostly spliceosome) and abnormal karyotype might compromise survival in PV and ET. Life-expectancy in ET is inferior to the control population. Driver mutations have not been shown to affect survival in ET. Risk of thrombosis is higher in JAK2-mutated ET. Leukemic transformation rates at 10 years are estimated at <1% for ET and 3% for PV. Thrombosis Risk: In PV, 2 risk categories are considered: high (age > 60 years or thrombosis history present) and low (absence of both risk factors); in ET, 4 risk categories are considered: very low (age ≤ 60 years, no thrombosis history, JAK2 wild-type), low (same as very low but JAK2 mutation present), intermediate (age > 60 years, no thrombosis history, JAK2 wild-type) and high (thrombosis history present or age > 60 years with JAK2 mutation). Risk-Adapted Therapy: The main goal of therapy in both PV and ET is to prevent thrombohemorrhagic complications. All patients with PV require phlebotomy to keep hematocrit below 45% and once- or twice-daily aspirin (81 mg), in the absence of contraindications. Very low-risk ET might not require therapy while aspirin therapy is advised for low-risk disease. Cytoreductive therapy is recommended for high-risk ET and PV but it is not mandatory for intermediate-risk ET. First-line drug of choice for cytoreductive therapy, in both ET and PV, is hydroxyurea and second-line drugs of choice are interferon-α and busulfan. We do not recommend treatment with ruxolutinib in PV, unless in the presence of severe and protracted pruritus or marked splenomegaly that is not responding to the aforementioned drugs.

Predilection of Low Protein C-induced Spontaneous Atherothrombosis for the Right Coronary Sinus in Apolipoprotein E deficient mice

Silencing of anticoagulant protein C using RNA interference (siProc) evokes low incident but spontaneous atherothrombosis in the aortic root of apolipoprotein E–deficient (Apoe^−/−) mice. The aims of the current study were (1) to analyze if plaque characteristics or circulating factors could be linked to atherothrombosis susceptibility, (2) to increase the incidence of atherothrombosis by transiently increasing blood pressure, and (3) to direct atherothrombosis to an additional predefined vascular site by applying a semi-constrictive collar around the carotid artery. siProc-driven spontaneous atherothrombosis in the aortic root of Apoe^−/− mice was reproduced and occurred at an incidence of 23% (9 out of 39 mice), while the incidence of collar-induced atherothrombosis in the carotid artery was 2.6% (1 out of 39 mice). Treatment with phenylephrine, to transiently increase blood pressure, did not increase atherothrombosis in the aortic root of the Apoe^−/− mice nor in the carotid arteries with collars. Plaques in the aortic root with an associated thrombus were lower in collagen and macrophage content, and mice with atherothrombosis had significantly more circulating platelets. Plasma protein C, white blood cell counts, total cholesterol, fibrinogen, serum amyloid A, and IL-6 were not different amongst siProc treated mice with or without thrombosis. Remarkably, our data revealed that thrombus formation preferably occurred on plaques in the right coronary sinus of the aortic root. In conclusion, there is a predilection of low protein C-induced spontaneous atherothrombosis in Apoe^−/− mice for the right coronary sinus, a process that is associated with an increase in platelets and plaques lower in collagen and macrophage content.

Expression of CD markers in JAK2V617F positive myeloproliferative neoplasms: Prognostic significance

Myeloproliferative neoplasms (MPNs) are clonal stem cell disorders characterized by the presence of JAK2^V617F mutation. Thrombohemorrhagic as well as autoimmune or inflammatory phenomena are common clinical outcomes of these disorders. Recent studies have shown that abnormality in frequency and function of blood cells manifested by an alteration in CD markers' expression patterns play a key role in these complications. So, there may be a relationship between CD markers' expressions and prognosis of JAK2^V617F positive MPNs. Therefore, in this review, we have focused on these abnormalities from the perspective of changing expressions of CD markers and assessment of the relationship between these changes with prognosis of JAK2^V617F positive MPNs. It can be stated that the abnormal expression of a large number of CD markers can be used as a prognostic biomarker for clinical outcomes including thrombohememorrhagic events, as well as autoimmune and leukemic transformation in JAK2^V617F positive MPNs. Considering the possible role of CD markers' expressions in JAK2^V617F MPNs prognosis, further studies are needed to confirm the relationship between the expression of CD markers with prognosis to be able to find an appropriate therapeutic approach via targeting CD markers.

Austrian recommendations for the management of polycythemia vera

Polycythemia vera (PV) is a clonal disease arising from hematopoietic stem cells. Erythrocytosis is the hallmark of the disease but leukocytosis, thrombocytosis and splenomegaly may also be present. Thromboembolic complications occur in about 20% of patients. Circulatory disturbances as well as pruritus represent frequent symptoms of the disease. Mutations in the JAK2 gene are present in 95% of patients in exon 14 (V617F) and in 3% in exon 12. The main goal of the treatment for patients with PV is the prevention of thromboembolic events, transformation to myelofibrosis and acute myeloid leukemia. Interferon alpha and hydroxyurea are used as first-line treatment for high risk patients. For patients unresponsive to first-line therapy ruxolitinib is available.

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.

Intrinsic apoptosis circumvents the functional decline of circulating platelets but does not cause the storage lesion

BAK/BAX depletion in murine platelets reveals that intrinsic apoptosis is not required for the development of the platelet storage lesion. Restriction of platelet life span by intrinsic apoptosis is pivotal to maintain a functional, hemostatically reactive platelet population.

The Importance of the Full Blood Count in Cerebral Ischemia: A Review of 609 Consecutive Young Patients with Stroke and Transient Ischemic Attacks

BACKGROUND

Almost half of ischemic strokes in young individuals are cryptogenic. Thrombophilia testing is routinely sent despite limited evidence linking to arterial cerebrovascular events. A full blood count may identify underlying hematological disorder.

METHODS

We retrospectively reviewed all patients younger than 60 years with stroke and transient ischemic attack (TIA) presenting to a regional hyperacute stroke unit and daily TIA clinic from January 2015 to August 2016. We examined hematocrit level and platelet count, and whether abnormalities were further investigated. We examined if primary hematological disorders associated with stroke were considered, specifically myeloproliferative diseases (MPDs) and thrombotic thrombocytopenic purpura (TTP).

RESULTS

Of 609 patients who presented with stroke or TIA, there were 161 abnormalities in hematocrit level or platelet count in 153 patients (25.1%). One hundred sixteen patients had high hematocrit levels (19%), 19 had thrombocytosis (3.1%), 26 had thrombocytopenia (4.3%), and 8 had abnormalities in both lineages (1.3%). A total of 119 patients had repeat testing (74%). Molecular investigations for MPD were warranted in 19 patients (3.1%), performed in 3 patients (.5%) with 2 patients subsequently diagnosed. ADAMTS13 analysis was indicated in 10 patients with thrombocytopenia, performed in 2 patients with 1 diagnosed with TTP thereafter.

CONCLUSIONS

One quarter of our cohort (n = 153) had abnormalities in hematocrit and/or platelets. MPD or TTP was present in 3 of the 5 patients specifically investigated. At least 22 patients (14%) merited further investigation. Although primary hematological disorders are rare in stroke aetiology, the full blood count is important to exclude known causes of arterial cerebrovascular events in young patients.

Chronic kidney disease in the BCR-ABL1-negative myeloproliferative neoplasm: a single-center retrospective study

Background/Aims

Renal complications related to BCR-ABL1-negative myeloproliferative neoplasms (MPNs) have not been examined fully in Asian populations.

METHODS

We analyzed estimated glomerular filtration rate (eGFR) and its changes with time retrospectively in patients with BCR-ABL1-negative MPN from 2005 to 2015.

RESULTS

The prevalence of chronic kidney disease (CKD) was 11% (6.6% having stage 3 and 4.4% having stage 4). In a linear regression analysis of eGFR versus time (years), overall, patients showed increased eGFR (mL/min/1.73 m2) by 0.51 (95% confidence interval [CI], -0.30 to 1.33; p = 0.22). Patients with polycythemia vera (PV), and those treated with hydroxyurea, showed statistically significant increases in eGFR (1.59; 95% CI, 0.28 to 2.90; p = 0.02 in PV; and 1.55; 95% CI, 0.56 to 2.54; p = 0.02 in treatment with hydroxyurea). In total, 17 patients (20.5%) showed rapid loss of eGFR (< -3 mL/min/1.73 m2 per year). This rapid loss in eGFR was associated with a higher incidence of kidney disease (23.5% vs. 6.1%, p = 0.05) and a higher percentage of patients with high neutrophil (> 7.0 × 109 /L) and high monocyte (> 0.7 × 109 /L) counts (76.5% vs. 50%, p = 0.05; 52.9% vs. 28.8%, p = 0.06, respectively). More patients had high serum lactate dehydrogenase (> 500 U/L) levels (52.9% vs. 25.8%, p = 0.03) at diagnosis.

Conclusions

CKD is prevalent in patients with BCR-ABL1-negative MPN. Active cytoreductive therapy has the potential to improve kidney function in BCR-ABL1-negative MPN.

A rare CALR variant mutation and a review of CALR in essential thrombocythemia

Essential thrombocythemia (ET) is an indolent myeloproliferative neoplasm characterized by megakaryocyte hyperplasia, thrombocytosis, thrombotic and hemorrhagic complications, and potential transformation into myelofibrosis and acute myeloid leukemia. The vast majority of cases are driven by a somatic mutation in JAK2, CALR, or MPL. CALR, a gene that codes for the calcium-binding chaperone calreticulin, is the predominant mutation in patients with non-mutated JAK2 essential thrombocythemia, accounting for 20-25% of the overall somatic mutation frequency in ET. In this brief review of ET, we introduce a rare CALR mutation through a case presentation of a 58-year-old man with diffuse pulmonary emboli in the setting of thrombocytosis. We subsequently characterize the main types of CALR mutations and their value in diagnosis and prognosis of disease course, and lastly discuss the current clinical approach to ET.

Prognostication in Philadelphia Chromosome Negative Myeloproliferative Neoplasms: a Review of the Recent Literature

PURPOSE OF REVIEW

The prognosis for patients with Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPNs) is highly variable. All Ph-negative MPNs carry an increased risk for thrombotic complications, bleeding, and leukemic transformation. Several clinical, biological, and molecular prognostic factors have been identified in recent years, which provide important information in guiding management of patients with Ph-negative MPNs. In this review, we critically evaluate the recent published literature and discuss important new developments in clinical and molecular factors that impact survival, disease transformation, and thrombosis in patients with polycythemia vera, essential thrombocythemia, and primary myelofibrosis.

RECENT FINDINGS

Recent studies have identified several clinical factors and non-driver mutations to have prognostic impact on Ph-negative MPNs independent of conventional risk stratification and prognostic models. In polycythemia vera (PV), leukocytosis, abnormal karyotype, phlebotomy requirement on hydroxyurea, increased bone marrow fibrosis, and mutations in ASXL1, SRSF2, and IDH2 were identified as additional adverse prognostic factors. In essential thrombocythemia (ET), JAK2 V617F mutation, splenomegaly, and mutations in SH2B3, SF3B1, U2AF1, TP53, IDH2, and EZH2 were found to be additional negative prognostic factors. Bone marrow fibrosis and mutations in ASXL1, SRSF2, EZH2, and IDH1/2 have been found to be additional prognostic factors in primary myelofibrosis (PMF). CALR mutations appear to be a favorable prognostic factor in PMF, which has not been clearly demonstrated in ET. The prognosis for patients with PV, ET, and PMF is dependent upon the presence or absence of several clinical, biological, and molecular risk factors. The significance of additional risk factors identified in these recent studies will need further validation in prospective studies to determine how they may be best utilized in the management of these disorders.

Incidence of venous thromboembolism and use of anticoagulation in hematological malignancies: Critical review of the literature

Venous Thromboembolism (VTE) frequently complicates the course of hematologic malignancies (HM) and its incidence is similar to that observed in high-risk solid tumors. Despite that, pharmacologic prophylaxis and treatment of VTE in patients with HM is challenging, mainly because a severe thrombocytopenia frequently complicates the course of treatments or may be present since diagnosis, thus increasing the risk of bleeding. Therefore, in this setting, safe and effective methods of VTE prophylaxis and treatment have not been well defined and hematologists generally refer to guidelines produced for cancer patients that give indications on anticoagulation in patients with thrombocytopenia. In this review, besides to summarize the incidence and the available data on prophylaxis and treatment of VTE in HM, we give some advices on how to use antithrombotic drugs in patients with HM according to platelets count.

Summary and Review of the Abstracts on Philadelphia-Negative Myeloproliferative Neoplasms Presented at Haematocon 2017

There are lot of grey zones in Philadelphia negative chronic myeloproliferative neoplasms (CMPNs) and that's the reason they are in hit list of researchers. Having a spectrum of disorders their diagnosis is very important and especially to differentiate from each other since they overlap with each other in many ways. Diagnosis doesn't start from lab but with clinical phenotype. Clinical phenotype not only able to provide us the diagnosis but also helps in management of the disease per se. When diagnosis comes, the old timer but an evergreen morphology plays an important role which along with the newer generation tool "molecular" helps in differentiating these disorders. Lot of studies have already come up from the world. Indian data has also started coming up. When we say about the Indian data nothing holds more important role than Indian Society of Haematology and Blood Transfusion, ISHBT. This small review will cover all papers with BCR-ABL negative CMPNs which were presented at the annual national conference of the ISHBT (Haematocon 2017) which was conducted at Guwahati. These abstract papers from various reputed institutes and centres will provide a short academic journey towards ongoing research activities at these places and will able to guide us regarding Philadelphia negative CMPNs and also stimulate our brain for some left or conflicted areas.

Phosphatidylserine-exposing blood and endothelial cells contribute to the hypercoagulable state in essential thrombocythemia patients

The mechanisms of thrombogenicity in essential thrombocythemia (ET) are complex and not well defined. Our objective was to explore whether phosphatidylserine (PS) exposure on blood cells and endothelial cells (ECs) can account for the increased thrombosis and distinct thrombotic risks among mutational subtypes in ET. Using flow cytometry and confocal microscopy, we found that the levels of PS-exposing erythrocytes, platelets, leukocytes, and serum-cultured ECs were significantly higher in each ET group [JAK2, CALR, and triple-negative (TN) (all P < 0.001)] than those in controls. Among ET patients, those with JAK2 mutations showed higher levels of PS-positive erythrocytes, platelets, neutrophils, and serum-cultured ECs than TN patients or those with CALR mutations, which show similar levels. Coagulation function assays showed that higher levels of PS-positive blood cells and serum-cultured ECs led to markedly shortened coagulation time and dramatically increased levels of FXa, thrombin, and fibrin production. This procoagulant activity could be largely blocked by addition of lactadherin (approx. 70% inhibition). Confocal microscopy showed that the FVa/FXa complex and fibrin fibrils colocalized with PS on ET serum-cultured ECs. Additionally, we found a relationship between D-dimer, prothrombin fragment F1 + 2, and PS exposure. Our study reveals a previously unrecognized link between hypercoagulability and exposed PS on cells, which might also be associated with distinct thrombotic risks among mutational subtypes in ET. Thus, blocking PS-binding sites may represent a new therapeutic target for preventing thrombosis in ET.

Risk factors for arterial versus venous thrombosis in polycythemia vera: a single center experience in 587 patients

In a recent International Working Group on Myeloproliferative Neoplasms Research and Treatment (IWG-MRT) study, prior arterial events and hypertension were predictors of subsequent arterial thrombosis whereas prior venous events and age ≥65 years predicted venous thrombosis in polycythemia vera (PV). In the current study, we sought to validate the above findings and identify additional predictors of arterial versus venous thrombosis. At a median follow up of 109 months, thrombosis after diagnosis occurred in 128 (22%) patients; 82 (14%) arterial and 57 (10%) venous events. On multivariate analysis, prior arterial events (<0.0001), hyperlipidemia (p = 0.03), and hypertension (p = 0.02) predicted subsequent arterial events. In comparison, prior venous events (p = 0.05), leukocytosis ≥11 × 10⁹/L (p = 0.002), and major hemorrhage (p = 0.02) were predictors of subsequent venous events. Salient associations with arterial thrombosis included age ≥ 60 years, hypertension, diabetes, hyperlipidemia and normal karyotype whereas age ≤ 60 years, females, palpable splenomegaly and history of major hemorrhage were associated with venous thrombosis. TET2 or ASXL1 mutations did not impact arterial nor venous thrombosis. In conclusion, we identify distinct associations for arterial versus venous thrombosis in PV and confirm that a prior arterial or venous thrombotic event is the most reliable predictor of subsequent events.

Do we need antiplatelet therapy in thrombocytosis? Pro

Thrombocytosis (defined as platelets >450 × 109/l) has several aetiologies. After having excluded spurious thrombocytosis (e. g., due to microspherocytes, schistocytes, cryoglobulins, or bacteria), the differential diagnosis of true thrombocytosis encompasses secondary causes (as diverse as inflammation, infection, malignancy, iron deficiency, or asplenia), primary hereditary (rare forms of familial thrombocytosis) and primary acquired entities (either in the context of a myelodys-plastic syndrome or more frequently a myeloproliferative neoplasia). This manuscript addresses the following aspects: 1) diagnostic approach to thrombocytosis; 2) various mechanisms leading to a high platelet count; 3) potential of some of these mechanisms to modulate platelet function, producing hyper-reactive platelets and thus exerting a direct impact on the thrombotic risk; 4) indication of anti-thrombotic treatment in patients with thrombocytosis. There is a single prospective randomized clinical trial showing the benefit of acetyl-salicylic acid in polycythaemia vera. For other types of primary thrombocytosis and for secondary forms, treatment decisions have to be individualized according to the patient thrombotic and bleeding risks, taking into account the mechanism causing thrombocytosis. This manuscript discusses experimental and clinical data suggesting that besides patients with essential thrombocythaemia and other forms of primary thrombocytosis also those with thrombocytosis in the context of chronic inflammation, malignancy, or exposure to high altitude might benefit from anti-platelet treatment.

Loss of pleckstrin-2 reverts lethality and vascular occlusions in JAK2V617F-positive myeloproliferative neoplasms

V617F driver mutation of JAK2 is the leading cause of the Philadelphia-chromosome-negative myeloproliferative neoplasms (MPNs). Although thrombosis is a leading cause of mortality and morbidity in MPNs, the mechanisms underlying their pathogenesis are unclear. Here, we identified pleckstrin-2 (Plek2) as a downstream target of the JAK2/STAT5 pathway in erythroid and myeloid cells, and showed that it is upregulated in a JAK2V617F-positive MPN mouse model and in patients with MPNs. Loss of Plek2 ameliorated JAK2V617F-induced myeloproliferative phenotypes including erythrocytosis, neutrophilia, thrombocytosis, and splenomegaly, thereby reverting the widespread vascular occlusions and lethality in JAK2V617F-knockin mice. Additionally, we demonstrated that a reduction in red blood cell mass was the main contributing factor in the reversion of vascular occlusions. Thus, our study identifies Plek2 as an effector of the JAK2/STAT5 pathway and a key factor in the pathogenesis of JAK2V617F-induced MPNs, pointing to Plek2 as a viable target for the treatment of MPNs.

Leukemic Transformation in Myeloproliferative Neoplasms: A Literature Review on Risk, Characteristics, and Outcome

Myeloproliferative neoplasms (MPNs) operationally include essential thrombocythemia, polycythemia vera, primary myelofibrosis (PMF), and prefibrotic PMF. All 4 MPN variants might progress into blast-phase disease (MPN-BP). For essential thrombocythemia, reported risk factors for leukemic transformation include advanced age, extreme thrombocytosis, anemia, leukocytosis, and sequence variants/mutations involving TP53 and EZH2 (for expansion of gene symbols, see www.genenames.org); for polycythemia vera, advanced age, leukocytosis, abnormal karyotype, mutations involving SRSF2 and IDH2, and treatment with pipobroman, chlorambucil, or P32; and for PMF, increased blast percentage, thrombocytopenia, abnormal karyotype, triple-negative driver mutational status, and sequence variants/mutations involving SRSF2, RUNX1, CEBPA, and SH2B3. The reported median survival figures for MPN-BP range from 1.5 to 2.5 months in patients treated with supportive care only, from 2.5 to 10 months in those receiving hypomethylating agents or low-dose chemotherapy, and from 3.9 to 9.4 months in those receiving induction chemotherapy. Three-year survival after allogeneic stem cell transplant was reported in 16% to 33% of patients. These observations validate the extremely poor prognosis associated with MPN-BP and the lack of effective drug therapy and highlight the need for urgent assessment of therapeutic values of investigational agents. In the meantime, affected patients might be best served with aggressive chemotherapy followed by allogeneic stem cell transplant after adequate blast clearance.

Imaging features of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are a heterogeneous group of haematological disorders including polycythaemia vera (PV), essential thrombocythaemia (ET), primary myelofibrosis (PMF), and chronic myeloid leukaemia (CML). These disorders show large overlap in genetic and clinical presentations, and can have many different imaging manifestations. Unusual thromboses, embolic events throughout the systemic or pulmonary vasculature, or osseous findings can often be clues to the underlying disease. There is limited literature about the imaging features of these disorders, and this may result in under-diagnosis. Multiple treatments are available for symptom control, and the development of multiple new pharmacological inhibitors has significantly improved morbidity and prognosis. Knowledge of these conditions may enable the radiologist to suggest an MPN as a possible underlying cause for certain imaging findings, particularly unexplained splanchnic venous thrombosis, i.e. in the absence of chronic liver disease or pancreatitis. The aim of the present review is to outline using examples the different categories of MPN and illustrate the variety of radiological findings associated with these diseases.

Hemorrhage and Infarction of the Conjunctiva and Orbit in Essential Thrombocythemia

An 82-year-old woman who had a history of essential thrombocythemia presented with ocular pain, bleeding, and decreased visual acuity of the left eye. Orbital computed tomography revealed a relatively well-defined homogenous mass-like lesion in the left subconjunctival and intraconal space. Conjunctival biopsy showed acute inflammation with necrosis, vascular ectasia with thrombosis and hemorrhage. After the treatment with hydroxyurea and anagrelide, her symptom and lesion were markedly improved. Hematologic disorders like essential thrombocythemia should be considered in patients with severe spontaneous bleeding around the eye.

Bumpy road to the diagnosis of polycythaemia vera

Polycythaemia vera (PV) is the most common myeloproliferative neoplasm, characterised by increased red cell mass that can present as an unspecified symptom or a thrombohaemorrhagic event. Its diagnosis is based on the presence of erythrocytosis, the identification of the Janus kinase 2 mutation and bone marrow aspirate or biopsy alterations. The challenge of this disease lies on the treatment approach. Its cornerstone is phlebotomy, but depending on the vascular risk, it can include cytoreductive agents, low-dose aspirin or even anticoagulation. We present the case of a 75-year-old woman, whose inaugural presentation of PV was an arterial peripheral occlusion followed by three recurrent events in the same arterial region and a pulmonary embolism. A phlebotomy was initially performed and, after the diagnosis was made, the patient was initiated on low-dose aspirin and anticoagulation with favourable outcome.

Medical Management of Extensive Arterial Thromboembolism in a Patient with Essential Thrombocythemia and Warfarin Failure

Chronic myeloproliferative disorders share a stem cell-derived clonal myeloproliferation. This group of disorders include essential thrombocythemia (ET), polycythemia vera (PV), chronic myeloid leukemia, and primary myelofibrosis (PMF), with the respective features of thrombocytosis, erythrocytosis, and bone marrow fibrosis. These disorders can be associated with genetic mutations affecting protein tyrosine kinases, resulting in different configurations of abnormal signal transduction. The Janus tyrosine kinase 2 mutation can be used as a key diagnostic tool for diagnosing MPDs, specifically, ET, PV, and PMF. Patients with ET and PV are at an increased risk for thromboembolic and hemorrhagic events. We present a unique case of ET causing extensive arterial thromboembolism, despite being on adequate antithrombotic agents including warfarin and aspirin.

Driver mutations (JAK2V617F, MPLW515L/K or CALR), pentraxin-3 and C-reactive protein in essential thrombocythemia and polycythemia vera

Background

The driver mutations JAK2V617F, MPLW515L/K and CALR influence disease phenotype of myeloproliferative neoplasms (MPNs) and might sustain a condition of chronic inflammation. Pentraxin 3 (PTX3) and high-sensitivity C-reactive protein (hs-CRP) are inflammatory biomarkers potentially useful for refining prognostic classification of MPNs.

Methods

We evaluated 305 with essential thrombocythemia (ET) and 172 polycythemia vera (PV) patients diagnosed according to the 2016 WHO criteria and with full molecular characterization for driver mutations.

Results

PTX3 levels were significantly increased in carriers of homozygous JAK2V617F mutation compared to all the other genotypes and triple negative ET patients, while hs-CRP levels were independent of the mutational profile. The risk of haematological evolution and death from any cause was about 2- and 1.5-fold increased in individuals with high PTX-3 levels, while the thrombosis rate tended to be lower. High hs-CRP levels were associated with risk of haematological evolution, death and also major thrombosis. After sequential adjustment for potential confounders (age, gender, diagnosis and treatments) and the presence of JAK2V617F homozygous status, high hs-CRP levels remained significant for all outcomes, while JAK2V617F homozygous status as well as treatments were the factors independently accounting for adverse outcomes among patients with high PTX3 levels.

Conclusions

These results provide evidence that JAK2V617F mutation influences MPN-associated inflammation with a strong correlation between allele burden and PTX3 levels. Plasma levels of hs-CRP and PTX3 might be of prognostic value for patients with ET and PV, but their validation in future prospective studies is needed.

Thrombocytosis in splenic trauma: In-hospital course and association with venous thromboembolism

INTRODUCTION

Thrombocytosis is common following elective splenectomy and major trauma. However, little is known about the in-hospital course of platelet count (PC) and incidence of thrombocytosis after splenic trauma. Extreme thrombocytosis (PC>1000×10⁹) is associated with increased risk of venous thromboembolism (VTE) in primary thrombocytosis leading to the use of acetylsalicylic acid (ASA) for risk reduction, but the need for this agent in splenic trauma is undefined.

METHODS

Retrospective cohort study of all patients with splenic trauma between April 1, 2010 and March 31, 2014. The in-hospital course of PC was assessed based on splenic injury management type. The association of management type with thrombocytosis was evaluated using a multivariable logistic regression model adjusting for potential confounders. The association of thrombocytosis, extreme thrombocytosis, and ASA use for the outcome of VTE was explored.

RESULTS

156 patients were eligible, PC initially increased in all patients with the highest peak after total splenectomy. The incidence of thrombocytosis was 41.0% (64/156). Thrombocytosis was more likely following splenectomy compared with spleen preserving strategies independent of length of stay, injury grade, ISS, age and transfusion (OR 7.58, 95% CI: 2.26-25.45). Splenectomy was associated with extreme thrombocytosis (OR 10.39, 95% CI: 3.59-30.07).

CONCLUSIONS

Thrombocytosis in splenic trauma is more likely after splenectomy than with spleen preserving strategies. Splenectomy is associated with extreme thrombocytosis. There was insufficient data in our study to determine the use of ASA as primary prevention of VTE after splenic trauma.

Polycythemia vera and essential thrombocythemia: 2017 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Polycythemia Vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms respectively characterized by erythrocytosis and thrombocytosis; other disease features include leukocytosis, splenomegaly, thrombosis, bleeding, microcirculatory symptoms, pruritus, and risk of leukemic or fibrotic transformation.

DIAGNOSIS

PV is defined by a JAK2 mutation, whose absence, combined with normal or increased serum erythropoietin level, makes the diagnosis unlikely. JAK2, CALR, and MPL mutations are the mutually exclusive "driver" mutations in ET with respective incidences of 55%, 25%, and 3%; approximately 17% are triple-negative. However, the same molecular markers might also be present in prefibrotic myelofibrosis, whose morphological distinction from ET is prognostically relevant.

SURVIVAL AND LEUKEMIC/FIBROTIC TRANSFORMATION

Median survivals are approximately 14 years for PV and 20 years for ET; the corresponding values for younger patients (age <60 years) are 24 and 33 years. Life-expectancy in ET is inferior to the control population. Driver mutational status has not been shown to affect survival in ET whereas the presence of JAK2/MPL mutations has been associated with higher risk of arterial thrombosis and that of MPL with higher risk of fibrotic progression. Risk factors for overall survival in both ET and PV include advanced age, leukocytosis and thrombosis. Leukemic transformation rates at 20 years are estimated at <10% for PV and 5% for ET; fibrotic transformation rates are slightly higher. Most recently, ASXL1, SRSF2, and IDH2 mutations have been associated with inferior overall, leukemia-free or fibrosis-free survival in PV; similarly adverse mutations in ET included SH2B3, SF3B1, U2AF1, TP53, IDH2, and EZH2.

THROMBOSIS RISK STRATIFICATION

Current risk stratification in PV and ET is designed to estimate the likelihood of recurrent thrombosis. Accordingly, PV includes two risk categories: high-risk (age >60 years or thrombosis history) and low-risk (absence of both risk factors). In ET, risk stratification includes four categories: very low risk (age ≤60 years, no thrombosis history, JAK2/MPL un-mutated), low risk (age ≤60 years, no thrombosis history, JAK2/MPL mutated), intermediate risk (age >60 years, no thrombosis history, JAK2/MPL un-mutated), and high risk (thrombosis history or age >60 years with JAK2/MPL mutation). In addition, presence of extreme thrombocytosis (platelets >1000 × 10(9)/L) might be associated with acquired von Willebrand syndrome (AvWS) and, therefore, risk of bleeding.

RISK-ADAPTED THERAPY

The main goal of therapy in PV and ET is to prevent thrombohemorrhagic complications. All patients with PV require phlebotomy to keep hematocrit below 45% and once-daily aspirin (81 mg). In addition, high-risk patients with PV require cytoreductive therapy. Very low risk ET patients might not require any form of therapy while low-risk patients require at least once-daily aspirin therapy. Cytoreductive therapy is also recommended for high-risk ET patients but it is not mandatory for intermediate-risk patients. First-line drug of choice for cytoreductive therapy, in both ET and PV, is hydroxyurea and second-line drugs of choice are interferon-α and busulfan. We currently do not recommend treatment with ruxolutinib or other JAK2 inhibitors in PV or ET, unless in the presence of severe and protracted pruritus or marked splenomegaly that is not responding to the aforementioned drugs. Screening for AvWS is recommended before administrating aspirin, in the presence of extreme thrombocytosis. Am. J. Hematol. 92:95-108, 2017. © 2016 Wiley Periodicals, Inc.

Repetitive Transient Ischaemic Attacks Secondary to a Floating Carotid Artery Thrombus in a Young Patient with Essential Thrombocythemia

A free-floating carotid artery thrombus is a very rare ultrasonographical finding in patients with acute ischemic cerebrovascular events. One of the main causes of this presentation is represented by the hypercoagulability status of the patients. We report the case of a young male patient who presented with several transient ischaemic attacks secondary to a mobile thrombus in the left carotid sinus. Two hematological abnormalities, essential thrombocytosis and methylene tetrahydrofolate reductase mutation were found to be related to the thrombus formation. The role of the latter in the pathogenesis of ischemic stroke is not well documented in the literature. Following antiplatelet and anticoagulant medication, there was a fast dissolution of the thrombus, followed by a favorable clinical outcome. Neurologists should be aware that young patients with stroke require extensive imagistic and laboratory screening for an accurate etiological diagnosis.

Relationship between JAK2V617F mutation, allele burden and coagulation function in Ph-negative myeloproliferative neoplasms

OBJECTIVES

Our aim was to explore the relationship between JAK2V617F mutation allele burden and hematological parameters especially in coagulation function in Chinese population.

METHODS

This study included 133 Ph-negative myeloproliferative neoplasms (MPNs) patients between 2013 and 2016. All the clinical and experimental data of patients were collected at the time of the diagnosis without any prior treatment, including blood parameters, coagulation function, splenomegaly, vascular events and chromosome karyotype. PCR and qPCR were used to detect JAK2V617F mutation and JAK2V617F mutation allele burden.

RESULTS

In polycythemia vera patients, a positive correlation between the allele burden of JAK2V617F mutation and PLT counts was found; in essential thrombocythemia (ET) patients, WBC counts, RBC counts, HB, and HCT were higher in mutated patients than in wild-type patients. Furthermore, PT-INR was higher in ET and PMF mutated patients. In addition, a positive correlation between the allele burden of JAK2V617F mutation and activated partial thromboplastin time (APTT) was observed in JAK2V617F mutated ET patients.

CONCLUSIONS

Higher hematologic parameters including counts of WBC, RBC, and PLT are closely associated with JAK2V617F mutation and its burden in Ph-negative MPNs; importantly, PT-INR, APTT are also related to JAK2V617F mutation and allele burden. Thus, our data indicate that JAK2V617F mutation allele burden might not only represent the burden of MPN but also alter the coagulation function.

Comprehensive Gene expression meta-analysis and integrated bioinformatic approaches reveal shared signatures between thrombosis and myeloproliferative disorders

Thrombosis is a leading cause of morbidity and mortality in patients with myeloproliferative disorders (MPDs), particularly polycythemia vera (PV) and essential thrombocythemia (ET). Despite the attempts to establish a link between them, the shared biological mechanisms are yet to be characterized. An integrated gene expression meta-analysis of five independent publicly available microarray data of the three diseases was conducted to identify shared gene expression signatures and overlapping biological processes. Using INMEX bioinformatic tool, based on combined Effect Size (ES) approaches, we identified a total of 1,157 differentially expressed genes (DEGs) (697 overexpressed and 460 underexpressed genes) shared between the three diseases. EnrichR tool's rich library was used for comprehensive functional enrichment and pathway analysis which revealed "mRNA Splicing" and "SUMO E3 ligases SUMOylate target proteins" among the most enriched terms. Network based meta-analysis identified MYC and FN1 to be the most highly ranked hub genes. Our results reveal that the alterations in biomarkers of the coagulation cascade like F2R, PROS1, SELPLG and ITGB2 were common between the three diseases. Interestingly, the study has generated a novel database of candidate genetic markers, pathways and transcription factors shared between thrombosis and MPDs, which might aid in the development of prognostic therapeutic biomarkers.

Do we need antiplatelet therapy in thrombocytosis? Contra. Proposal for an individualized risk-adapted treatment

Thrombocytosis is a frequent laboratory finding but not a diagnosis. Therefore, elevated platelet counts (>450 x 10⁹/l) require careful diagnostic work-up to differentiate between reactive thrombocytosis (RT), caused by various conditions, and essential thrombocythemia (ET), a myeloproliferative neoplasm (MPN). In either setting, aspirin is widely used in clinical practice. However, RT (even at platelet counts >1000 x 10⁹/l) has never been shown to cause thrombosis or bleeding due to acquired von Willebrand factor defects in association with high platelet counts. Identification of reactive conditions and appropriate therapy of the underlying disorder are most relevant. By contrast to RT, ET and related MPN can be associated with thrombosis and/or hemorrhage. Current recommendations suggest the use of low-dose aspirin in all patients with ET unless contraindicated. However, the strength of this recommendation is weak, i. e. evidence level IIb grade B. A potential benefit of aspirin used for primary thromboprophylaxis in ET is mostly derived from the ECLAP study in polycythemia vera (PV). However, translating study results from PV to ET appears to be highly questionable and may be biased. In the absence of robust data regarding the benefit-risk balance of aspirin in ET, it appears reasonable (1) to stratify patients according to their individual thrombotic and bleeding risk, (2) to restrict the use of aspirin to high-risk categories and patients with microcirculatory disturbances, (3) to test for pharmacological efficacy (COX-1 inhibition; measurement of TXB₂), and (4) to modify the aspirin dosing regimen (twice instead of once daily) if required.