C-Mannosyl tryptophan is a novel biomarker for thrombocytosis of myeloproliferative neoplasms.

C-Mannosyl tryptophan (CMW), a unique glycosylated amino acid, is considered to be produced by degradation of C-mannosylated proteins in living organism. Although protein C-mannosylation is involved in the folding and secretion of substrate proteins, the pathophysiological function in the hematological system is still unclear. This study aimed to assess CMW in the human hematological disorders. The serum CMW levels of 94 healthy Japanese workers were quantified using hydrophilic interaction liquid chromatography. Platelet count was positively correlated with serum CMW levels. The clinical significance of CMW in thrombocytosis of myeloproliferative neoplasms (T-MPN) including essential thrombocythemia (ET) were investigated. The serum CMW levels of the 34 patients with T-MPN who presented with thrombocytosis were significantly higher than those of the 52 patients with control who had other hematological disorders. In patients with T-MPN, serum CMW levels were inversely correlated with anemia, which was related to myelofibrosis (MF). Bone marrow biopsy samples were obtained from 18 patients with ET, and serum CMW levels were simultaneously measured. Twelve patients with bone marrow fibrosis had significantly higher CMW levels than 6 patients without bone marrow fibrosis. Collectively, these results suggested that CMW could be a novel biomarker to predict MF progression in T-MPN.

Predictive significance of high neutrophil ratio for thrombosis in myeloproliferative neoplasms: JSH-MPN-R18 subanalysis.

Thrombosis in myeloproliferative neoplasms (MPNs) is an important clinical problem, and risk-stratified management is essential. To identify the clinical characteristics of thrombosis in patients with MPNs, a nationwide multi-institutional retrospective analysis (JSH-MPN-R18) was conducted. The aim of the present study was to perform a sub-analysis of JSH-MPN-R18 findings to clarify the predictive parameters for thrombosis among complete blood count (CBC) results. Among the patients enrolled in JSH-MPN-R18, those with essential thrombocythemia (ET; n = 1152) and polycythemia vera (PV; n = 456) were investigated. We analyzed and compared CBC parameters between patients with and those without any thrombotic events using Welch's T-test. Statistical analyses were performed using the R statistical software. Thrombotic events were observed in 74 patients with ET. In multivariate analysis, only the neutrophil ratio was slightly but significantly higher for ET patients with thrombosis than for those without (p < 0.05). Of note, the absolute neutrophil count (aNeu) was considered a useful predictive tool for thrombosis among patients classified as low-risk according to the revised International Prognostic Score of Thrombosis for Essential Thrombocythemia. Among PV patients, those with thrombosis showed significantly higher hematocrit and aNeu than did those without thrombosis. As a thrombosis-associated factor, the neutrophil ratio was slightly but significantly elevated in patients with ET. This myeloid skew might reflect a higher value of JAK2 V617F allelic frequency in patients with ET with thrombosis; this was not clarified in JSH-MPN-R18. Further accumulation of evidence, including genetic information for JAK2 and other passenger mutations, is warranted.

Myeloproliferative Neoplasms Transcriptome Reveals Pro-Inflammatory Signature and Enrichment in Peripheral Blood Monocyte-Related Genes.

Myeloproliferative neoplasms (MPN) are hematological diseases associated with genetic driver mutations in the JAK2, CALR, and MPL genes and exacerbated oncoinflammatory status. Analyzing public microarray data from polycythemia vera (n = 41), essential thrombocythemia (n = 21), and primary myelofibrosis (n = 9) patients' peripheral blood by in silico approaches, we found that pro-inflammatory and monocyte-related genes were differentially expressed in MPN patients' transcriptome. Genes related to cell activation, secretion of pro-inflammatory and pro-angiogenic mediators, activation of neutrophils and platelets, coagulation, and interferon pathway were upregulated in monocytes compared to controls. Together, our results suggest that molecular alterations in monocytes may contribute to oncoinflammation in MPN.

Raman Spectroscopy of Blood Serum for Essential Thrombocythemia Diagnosis: Correlation with Genetic Mutations and Optimization of Laser Wavelengths.

Essential thrombocythemia (ET) is a type of myeloproliferative neoplasm that increases the risk of thrombosis. To diagnose this disease, the analysis of mutations in the Janus Kinase 2 (JAK2), thrombopoietin receptor (MPL), or calreticulin (CALR) gene is recommended. Disease poses diagnostic challenges due to overlapping mutations with other neoplasms and the presence of triple-negative cases. This study explores the potential of Raman spectroscopy combined with machine learning for ET diagnosis. We assessed two laser wavelengths (785, 1064 nm) to differentiate between ET patients and healthy controls. The PCR results indicate that approximately 50% of patients in our group have a mutation in the JAK2 gene, while only 5% of patients harbor a mutation in the ASXL1 gene. Additionally, only one patient had a mutation in the IDH1 and one had a mutation in IDH2 gene. Consequently, patients having no mutations were also observed in our group, making diagnosis challenging. Raman spectra at 1064 nm showed lower amide, polysaccharide, and lipid vibrations in ET patients, while 785 nm spectra indicated significant decreases in amide II and C-H lipid vibrations. Principal Component Analysis (PCA) confirmed that both wavelengths could distinguish ET from healthy subjects. Support Vector Machine (SVM) analysis revealed that the 800-1800 cm-1 range provided the highest diagnostic accuracy, with 89% for 785 nm and 72% for 1064 nm. These findings suggest that FT-Raman spectroscopy, paired with multivariate and machine learning analyses, offers a promising method for diagnosing ET with high accuracy by detecting specific molecular changes in serum. Principal Component Analysis (PCA) confirmed that both wavelengths could distinguish ET from healthy subjects. Support Vector Machine (SVM) analysis revealed that the 800-1800 cm-1 range provided the highest diagnostic accuracy, with 89% for 785 nm and 72% for 1064 nm. These findings suggest that FT-Raman spectroscopy, paired with multivariate and machine learning analyses, offers a promising method for diagnosing ET with high accuracy by detecting specific molecular changes in serum.

Long-term pharmacodynamic and clinical effects of twice- versus once-daily low-dose aspirin in essential thrombocythemia: The ARES trial.

Patients with essential thrombocythemia (ET) are treated with once-daily low-dose aspirin to prevent thrombosis, but their accelerated platelet turnover shortens the antiplatelet effect. The short-term Aspirin Regimens in EsSential Thrombocythemia trial showed that twice-daily aspirin dosing restores persistent platelet thromboxane (TX) inhibition. However, the long-term pharmacodynamic efficacy, safety and tolerability of twice-daily aspirin remain untested. We performed a multicenter, randomized, open-label, blinded-endpoint, phase-2 trial in which 242 patients with ET were randomized to 100 mg aspirin twice- or once-daily and followed for 20 months. The primary endpoint was the persistence of low serum TXB2, a surrogate biomarker of antithrombotic efficacy. Secondary endpoints were major and clinically relevant non-major bleedings, serious vascular events, symptom burden assessed by validated questionnaires, and in vivo platelet activation. Serum TXB2 was consistently lower in the twice-daily versus once-daily regimen on 10 study visits over 20 months: median 3.9 ng/mL versus 19.2 ng/mL, respectively; p < .001; 80% median reduction; 95% CI, 74%-85%. No major bleeding occurred. Clinically relevant non-major bleedings were non-significantly higher (6.6% vs. 1.7%), and major thromboses lower (0.8% vs. 2.5%) in the twice-daily versus once-daily group. Patients on the twice-daily regimen had significantly lower frequencies of disease-specific symptoms and severe hand and foot microvascular pain. Upper gastrointestinal pain was comparable in the two arms. In vivo platelet activation was significantly reduced by the twice-daily regimen. In patients with ET, twice-daily was persistently superior to once-daily low-dose aspirin in suppressing thromboxane biosynthesis and reducing symptom burden, with no detectable excess of bleeding and gastrointestinal discomfort.

Platelet Factor 4 and Longevity of Patients with Essential Thromobocythemia: An Example of Antagonistic Pathogenic Pleiotropy.

This article presents the concept of Antagonistic Pathogenic Pleiotropy, in which an abnormality that causes a specific pathology can simultaneously reduce other morbidities through unrelated mechanisms, resulting in the pathology causing less morbidity or mortality than expected. The concept is illustrated by the case of essential thrombocythemia (ET). Patients with ET have substantially elevated platelets and are therefore expected to have increased thrombotic events leading to reduced life expectancy. However, patients with ET do not have reduced life expectancy. A possible explanation is that elevated platelets produce higher levels of platelet factor 4 (PF4), which has been found to reduce age-associated decline in immune and cognitive function in mice and has been suggested as a treatment for age-associated illness. The benefit of elevated PF4 is hypothesized to balance the increased morbidity from hematological causes. Searches for other indications where a well-defined pathology is not associated with concomitant reduction in overall mortality may be a route to identifying factors that could protect against, prevent, or treat chronic disease.

Resveratrol and tetrahydroisoquinoline effects on neutrophil sensitivity to NETosis formation in low-risk essential thrombocythemia patients.

INTRODUCTION: Recent studies scrutinize how NETosis (a unique cell death mechanism of neutrophil), impacts thrombosis patients with essential thrombocythemia (ET). This research evaluates the susceptibility of ET neutrophils to form NETs and tests two potential inhibitors, resveratrol (RSV) and tetrahydroisoquinoline (THIQ), in vitro. METHODS: Platelet-rich plasma from low-risk ET patients was used, along with neutrophils from both patients and controls. NET formation assays, with or without RSV and THIQ treatment after LPS stimulation, were conducted in a CO2 incubator. Evaluation included flow cytometry and fluorescence microscopy for NET formation and ELISA for TNFα, IL8, and vWF:Ag levels in patient and control plasma. RESULTS: Neutrophils from ET patients released more NETs than controls, confirmed by flow cytometry and fluorescence microscopy. Additionally, patients had significantly higher plasma levels of IL8 and TNFα compared to controls, while RSV was more effective than THIQ in reducing NETosis rates in these patients. CONCLUSIONS: In ET patients, a platelet counts over 1 million indicates the need for preventive treatment against thrombotic events. Similarly, in this study, RSV and THIQ significantly reduced the rate of NETosis in ET patients with higher platelet counts, and this role was more prominent in the case of the second inhibitor (RSV).

Cell-autonomous megakaryopoiesis associated with polyclonal hematopoiesis in triple-negative essential thrombocythemia.

A subset of essential thrombocythemia (ET) cases are negative for disease-defining mutations on JAK2, MPL, and CALR and defined as triple negative (TN). The lack of recurrent mutations in TN-ET patients makes its pathogenesis ambiguous. Here, we screened 483 patients with suspected ET in a single institution, centrally reviewed bone marrow specimens, and identified 23 TN-ET patients. Analysis of clinical records revealed that TN-ET patients were mostly young female, without a history of thrombosis or progression to secondary myelofibrosis and leukemia. Sequencing analysis and human androgen receptor assays revealed that the majority of TN-ET patients exhibited polyclonal hematopoiesis, suggesting a possibility of reactive thrombocytosis in TN-ET. However, the serum levels of thrombopoietin (TPO) and interleukin-6 in TN-ET patients were not significantly different from those in ET patients with canonical mutations and healthy individuals. Rather, CD34-positive cells from TN-ET patients showed a capacity to form megakaryocytic colonies, even in the absence of TPO. No signs of thrombocytosis were observed before TN-ET development, denying the possibility of hereditary thrombocytosis in TN-ET. Overall, these findings indicate that TN-ET is a distinctive disease entity associated with polyclonal hematopoiesis and is paradoxically caused by hematopoietic stem cells harboring a capacity for cell-autonomous megakaryopoiesis.

Comparison of the effects between MPL and JAK2V617F on thrombosis and peripheral blood cell counts in patients with essential thrombocythemia: a meta-analysis.

To assess the effects between MPL and JAK2V617F on the thrombosis risk and peripheral blood cell counts in patients with essential thrombocythemia (ET), we identified eligible studies from PubMed, Embase, and the Cochrane Library. Seven studies were ultimately included in this meta-analysis. All studies reported the peripheral blood cell counts of ET patients, and three of them reported the eligible thrombotic events. In comparing the effect of MPL versus JAK2V617F on thrombosis, 1257 ET patients (73 MPL + and 1184 JAK2V617F +) were included. MPL-positive (MPL +) ET patients had a higher risk of thrombosis than JAK2V617F-positive (JAK2V617F +) ET patients [RR = 1.80 (1.08-3.01), P = 0.025]. And 3453 ET patients (138 MPL + and 3315 JAK2V617F +) were included in the comparison of peripheral blood cell counts. Platelet counts of MPL + ET patients were higher than that of JAK2V617F + ET patients [WMD = 81.18 (31.77-130.60), P = 0.001]. MPL + ET patients had lower hemoglobin [WMD = - 11.66 (- 14.32 to - 9.00), P = 0.000] and white blood cell counts [WMD = - 1.01 (- 1.47 to - 0.56), P = 0.000] than JAK2V617F + ET patients. These findings indicate that the MPL mutation is a high-risk factor for thrombosis in ET patients, and it may be rational to include MPL mutation in the revised IPSET as a criterion for thrombosis prediction scores. And given the differences in peripheral blood, it is necessary to further study whether MPL + ET patients differ from JAK2V617F + ET patients in bleeding and survival.

Circulating Protein Disulfide Isomerase Is Associated with Increased Risk of Thrombosis in JAK2-Mutated Myeloproliferative Neoplasms.

PURPOSE: Thromboembolic events (TE) are the most common complications of myeloproliferative neoplasms (MPN). Clinical parameters, including patient age and mutation status, are used to risk-stratify patients with MPN, but a true biomarker of TE risk is lacking. Protein disulfide isomerase (PDI), an endoplasmic reticulum protein vital for protein folding, also possesses essential extracellular functions, including regulation of thrombus formation. Pharmacologic PDI inhibition prevents thrombus formation, but whether pathologic increases in PDI increase TE risk remains unknown. EXPERIMENTAL DESIGN: We evaluated the association of plasma PDI levels and risk of TE in a cohort of patients with MPN with established diagnosis of polycythemia vera (PV) or essential thrombocythemia (ET), compared with healthy controls. Plasma PDI was measured at enrollment and subjects followed prospectively for development of TE. RESULTS: A subset of patients, primarily those with JAK2-mutated MPN, had significantly elevated plasma PDI levels as compared with controls. Plasma PDI was functionally active. There was no association between PDI levels and clinical parameters typically used to risk-stratify patients with MPN. The risk of TE was 8-fold greater in those with PDI levels above 2.5 ng/mL. Circulating endothelial cells from JAK2-mutated MPN patients, but not platelets, demonstrated augmented PDI release, suggesting endothelial activation as a source of increased plasma PDI in MPN. CONCLUSIONS: The observed association between plasma PDI levels and increased risk of TE in patients with JAK2-mutated MPN has both prognostic and therapeutic implications.

Data-driven analysis of the kinetics of the JAK2V617F allele burden and blood cell counts during hydroxyurea treatment of patients with polycythemia vera, essential thrombocythemia, and primary myelofibrosis.

BACKGROUND: Hydroxyurea (HU) treatment of patients with essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF) (MPNs) normalizes elevated blood cell counts within weeks in the large majority of patients. Studies on the impact of HU upon the kinetics of the JAK2V617F allele burden, leukocyte, and platelet counts over time are scarce. PURPOSE: Using data-driven analysis as a novel tool to model the kinetics of the JAK2V617F allele burden and blood cell counts over time during treatment with HU. MATERIAL AND METHODS: Using serial measurements of JAK2V617F and correlation analysis of routine hematological values (the Hb-concentration, leukocyte count, platelet count, and lactic dehydrogenase), we present a detailed description and analysis of the kinetics of the JAK2V617F, leukocyte, and platelet counts and lactic dehydrogenase in 27 patients (PV = 18; ET = 7; PMF = 2), who were followed in the Danish randomized trial (DALIAH). To further analyze the JAK2V617F kinetics, we use a machine learning clustering algorithm to group the response patterns. RESULTS: Response patterns were highly heterogeneous, with clustering resulting in 3 groups and 3 outliers. In the large majority of patients, HU treatment was initially associated with a modest decline in the JAK2V617F allele burden in concert with a decline in leukocyte and platelet counts. However, HU did not induce a sustained and continuous decrease in the JAK2V617F allele burden. CONCLUSION: Using data-driven analysis of the JAK2V617F allele burden, leukocyte, and platelet kinetics during treatment with HU, we have shown that HU does not induce a sustained decrease in the JAK2V617F allele burden and neither induces sustained normalization of elevated cell counts in MPN patients. Our results may explain why MPN patients during treatment with HU still have a substantially increased risk of thrombosis.

Nonvitamin K Antagonist Oral Anticoagulant in Patients With Venous Thromboembolism and Polycythemia Vera or Essential Thrombocythemia: A Cohort Study.

ABSTRACT: Thrombosis is the most common adverse event in patients with polycythemia vera (PV) and essential thrombocythemia (ET). Little is known about the use of nonvitamin K antagonist oral anticoagulants (NOACs) in patients with myeloproliferative neoplasms. We sought to evaluate the efficacy and safety of NOAC in a cohort of patients with PV and ET, who experienced venous thromboembolism (VTE). We enrolled 48 consecutive patients with PV (70.8%) and ET [median age 67.0 (interquartile range, 58.5-72.0) years], who experienced VTE. Patients received apixaban (39.6%), rivaroxaban (33.3%), or dabigatran (27.1%). During a median follow-up of 30 (interquartile range, 20.5-41.5) months, recurrent thrombotic events and bleeding were recorded. Four thrombotic events (3.3 per 100 patient-years) were reported. Three deep vein thrombosis episodes (2.5 per 100 patient-years) were experienced by 2 patients with PV, who received apixaban (5 mg bid) and dabigatran (150 mg bid), and 1 patient with ET, who received dabigatran (150 mg bid). One ischemic stroke occurred in a patient with PV on rivaroxaban (20 mg/d). There was 1 major bleeding (0.8 per 100 patient-years) in a patient with ET on dabigatran (150 mg bid) and 3 clinically relevant nonmajor bleeding (2.5 per 100 patient-years): 2 on rivaroxaban (20 mg/d) and 1 on apixaban (5 mg bid). We did not observe significant differences related to the type of NOAC. Three deaths (2.5 per 100 patient-years) unrelated to either VTE or bleeding were recorded. This study shows that NOACs may be effective and safe as secondary prevention of VTE in patients with myeloproliferative neoplasms.

Disease and Clinical Characteristics of Patients With a Clinical Diagnosis of Essential Thrombocythemia Enrolled in the MOST Study.

Few data exist regarding the disease and clinical characteristics of patients with essential thrombocythemia (ET) in the United States. The ongoing, multicenter, noninterventional, prospective, Myelofibrosis and Essential Thrombocythemia Observational STudy (MOST) was designed to collect data pertaining to the demographics, clinical management, and patient-reported outcomes in patients with myelofibrosis or ET in the United States (NCT02953704). This analysis examines the clinical characteristics of patients with clinical diagnoses of high-risk or low-risk ET receiving ET-directed therapy at enrollment. At data cutoff (June 17, 2019), 1207 of 1234 enrolled patients were eligible for this analysis (median age, 70 years; 65% female; 88% white); 917 patients (76%) had mutation testing results available. The median time from ET diagnosis to study enrollment was 4.2 years. The majority of patients (87%) had high-risk ET. Of 333 patients with a history of thrombotic events, 247 had at least 1 event classified as arterial and/or venous. Platelet count was above normal range in 54% of patients. Hypertension (56%) was the most common comorbidity. At enrollment, the majority of patients (low-risk ET, 94%; high-risk ET, 79%) were receiving ET-directed monotherapy. Additional prospective analyses from MOST will help to identify areas of unmet need.

Hematopoietic expression of a chimeric murine-human CALR oncoprotein allows the assessment of anti-CALR antibody immunotherapies in vivo.

Myeloproliferative neoplasms (MPNs) are characterized by a pathologic expansion of myeloid lineages. Mutations in JAK2, CALR and MPL genes are known to be three prominent MPN disease drivers. Mutant CALR (mutCALR) is an oncoprotein that interacts with and activates the thrombopoietin receptor (MPL) and represents an attractive target for targeted therapy of CALR mutated MPN. We generated a transgenic murine model with conditional expression of the human mutant exon 9 (del52) from the murine endogenous Calr locus. These mice develop essential thrombocythemia like phenotype with marked thrombocytosis and megakaryocytosis. The disease exacerbates with age showing prominent signs of splenomegaly and anemia. The disease is transplantable and mutCALR stem cells show proliferative advantage when compared to wild type stem cells. Transcriptome profiling of hematopoietic stem cells revealed oncogenic and inflammatory gene expression signatures. To demonstrate the applicability of the transgenic animals for immunotherapy, we treated mice with monoclonal antibody raised against the human mutCALR. The antibody treatment lowered platelet and stem cell counts in mutant mice. Secretion of mutCALR did not constitute a significant antibody sink. This animal model not only recapitulates human MPN but also serves as a relevant model for testing immunotherapeutic strategies targeting epitopes of the human mutCALR.

Treatment of Essential Thrombocythemia with Anagrelide Is Associated with an Increased Risk of Worsened Kidney Function.

BACKGROUND AND PURPOSE: When choosing a cytoreduction method for patients suffering from essential thrombocythemia (ET), it is important to know the safety profile of the medicine used. Few articles have been published about the effects of hydroxycarbamide (hydroxyurea, HU) and anagrelide (ANA) on renal function in ET patients. This study is the largest analysis of nephrotoxicity of cytoreductive drugs used in ET therapy so far, which additionally includes risk factors for the progression of kidney disease and coexisting genetic mutation. EXPERIMENTAL APPROACH: The retrospective study included 310 patients diagnosed with ET. Demographic data, comorbidities, Cr, and estimated glomerular filtration rate (eGFR) were all taken into account prior to diagnosis and after 6 months of HU and ANA treatment. KEY RESULTS: A statistically significant difference was found between Cr and eGFR levels at baseline and after 6 months of treatment (p < 0.001). The applied treatment (HU and ANA) had the greatest impact on kidney function. ANA significantly increased the risk of worsening renal function in contrary to hydroxycarbamide after 6 months of treatment (eGFR change: median +1 mL/min/1.73 m2 [interquartile range (IQR) (-4)-(+7)] in the HU group vss. median -13 mL/min/1.73 m2 [IQR (-18)-(-6)] in the ANA group, odds ratio [OR] 7.92 95% confidence interval [95% CI] [4.17-15.08], p < 0.001). Lowering of eGFR <60 mL/min/1.73 m2 occurred in 31 patients (31.0%) from the ANA group and 10 people (4.8%) treated with HU (p = 0.000). In 1 patient from the ANA group, >50% decrease in eGFR was observed. The chance for an increase in Cr levels was higher in people with pre-existing arterial hypertension (OR 1.92 CI = 95% [1.21-3.05], p = 0.006). Sex, type of mutation found (JAK2 V617F or CALR), and previous renal impairment did not affect renal function after 6 months of treatment. In addition, there was no difference in the efficacy of ET treatment between HU and ANA (p = 0.998). CONCLUSIONS AND IMPLICATIONS: The observations indicate that ANA should be used in patients with ET with great caution and taking into account the risk of worsened kidney function.

Platelet Function and Turnover in Essential Thrombocythemia: A Systematic Review.

Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by increased platelet counts. ET has an incidence of 0.6 to 2.5 per 100,000 per year in Europe and North America. The disease is characterized by an increased thromboembolic risk, possibly caused by increased platelet counts. Furthermore, increased platelet function and/or increased platelet turnover may play a role. We aimed to explore: (1) whether platelet function and platelet turnover are increased in ET patients compared with healthy controls, and (2) whether these parameters are associated with increased thromboembolic risk and, therefore, may support decision-making on treatment in ET patients. We performed a systematic literature search on March 20, 2020 in Embase and PubMed following the Preferred Reporting Items for Systematic and Meta-Analysis (PRISMA) guidelines. In total, 1,923 articles were identified, 38 of which were included according to prespecified inclusion and exclusion criteria. Among the 38 studies, platelet activation (CD36 and CD62P) was investigated in 18 studies and was found to be increased in 12 of these. Platelet aggregation was investigated in 21 studies and was reported to be reduced in 20 of them. Platelet turnover (immature platelet count and mean platelet volume) was investigated in five studies with inconclusive results. No parameters were reported to predict the risk of thromboembolic events. In conclusion, platelet activation was increased in ET patients, but platelet aggregation was reduced. Future studies exploring markers of thromboembolic risk in ET patients are warranted.