Sailing in deceptive calm: Navigating the undercurrents of essential thrombocythaemia

The discovery of driver mutations in myeloproliferative neoplasms has significantly contributed to the management of patients with essential thrombocythaemia (ET). High-quality evidence has started to pave the way for targeted therapy. The review by Ferrer-Marín et al. further advances this discussion, highlighting how molecular profiling, including non-driver gene mutations, is set to revolutionize personalized treatment approaches for ET patients. Commentary on: Ferrer-Marín et al. Essential thrombocythemia: a contemporary approach with new drugs on the horizon. Br J Haematol 2024;204:1605-1616.

Thromboembolic events, major bleeding and mortality in essential thrombocythaemia and polycythaemia vera-A matched nationwide population-based study

Thromboembolic events and bleeding are known complications in essential thrombocythaemia (ET) and polycythaemia vera (PV). Using multiple Swedish health care registers, we assessed the rate of arterial and venous events, major bleeding, all-cause stroke and all-cause mortality in ET and PV compared to matched controls. For each patient with ET (n = 3141) and PV (n = 2604), five matched controls were randomly selected. In total, 327 and 405 arterial or venous events were seen in the group of ET and PV patients respectively. Compared to corresponding controls, the rate of venous thromboembolism, major bleeding and all-cause mortality per 100 treatment years was significantly increased among both ET (0.63, 0.79 and 3.70) and PV patients (0.94, 1.20 and 4.80). The PV patients also displayed a significantly higher rate of arterial events and all-cause stroke compared to controls. When dividing the cohort into age groups, we found a significantly higher rate of arterial and venous events in all age groups of PV patients, and the rate of all-cause mortality was significantly higher in both ET and PV patients in all ages above the age of 50. This study confirms that PV and ET are diseases truly marked by thromboembolic complications and bleeding.

Essential thrombocythaemia: A contemporary approach with new drugs on the horizon

Essential thrombocythaemia (ET) is a myeloproliferative neoplasm characterized by an increased risk of vascular complications and a tendency to progress to myelofibrosis and acute leukaemia. ET patients have traditionally been stratified into two thrombosis risk categories based on age older than 60 years and a history of thrombosis. More recently, the revised IPSET-thrombosis scoring system, which accounts for the increased risk linked to the JAK2 mutation, has been incorporated into most expert recommendations. However, there is increasing evidence that the term ET encompasses different genomic entities, each with a distinct clinical course and prognosis. Moreover, the effectiveness and toxicity of cytoreductive and anti-platelet treatments differ depending on the molecular genotype. While anti-platelets and conventional cytoreductive agents, mainly hydroxycarbamide (hydroxyurea), anagrelide and pegylated interferon, remain the cornerstone of treatment, recent research has shed light on the effectiveness of novel therapies that may help improve outcomes. This comprehensive review focuses on the evolving landscape of treatment strategies in ET, with an emphasis on the role of molecular profiling in guiding therapeutic decisions. Besides evidence-based management according to revised IPSET-thrombosis stratification, we also provide specific observations for those patients with CALR-, MPL-mutated and triple-negative ET, as well as cases with high-risk mutations.

Impact of non-driver gene mutations on thrombo-haemorrhagic events in ET patients

Risk-adapted therapy is recommended to prevent major clinical complications, such as thrombo-haemorrhagic events, in patients with essential thrombocythaemia (ET). In this study, we analysed the association between non-driver gene mutations and thrombo-haemorrhagic events in 579 patients with ET. ASXL1 and TP53 mutations were frequently identified in patients with ET complicated by thrombosis (22.7% and 23.1%, respectively), and the DNMT3A mutation was frequently identified in patients who experienced haemorrhage (15.2%). Multivariate analyses of thrombosis-free survival (TFS) revealed that ASXL1 and TP53 mutations are associated with thrombosis (hazard ratio [HR] = 3.140 and 3.752 respectively). Patients harbouring the ASXL1 or TP53 mutation had significantly worse TFS rates than those without mutation (p = 0.002 and p < 0.001 respectively). Furthermore, JAK2V617F-mutated patients with accompanying ASXL1 mutations showed significantly shorter TFS compared with those without ASXL1 mutations (p = 0.003). Multivariate analyses of haemorrhage-free survival (HFS) revealed that the DNMT3A mutation (HR = 2.784) is associated with haemorrhage. DNMT3A-mutated patients showed significantly shorter HFS than those without the mutation (p = 0.026). Non-driver gene mutations should be considered in treatment strategies and may provide important information for personalised treatment approaches.

The JAK2V617F mutation and the role of therapeutic agents in alleviating myeloproliferative neoplasm symptom burden

Alleviating symptom burden in patients with myeloproliferative neoplasms (MPNs) is imperative to achieving optimal management. Research remains to elucidate the relationship between the JAK2V617F (Janus kinase 2) mutation present in many MPN patients, and the symptomatology they experience. This retrospective study analysed data collected from MPN patients included in the Myeloproliferative Neoplasms: An In-depth Case-Control (MOSAICC) pilot study. The MPN Symptom Assessment Form was administered, and median symptom scores were compared between JAK2V617F-positive and JAK2V617F-negative groups. Multivariate logistic regression analysis adjusted for confounding variables. Overall, 106 MPN patients participated: 65.1% were JAK2V617F positive, 30.2% were JAK2V617F negative and 4.7% had an unknown status. Multivariate analysis revealed a low symptom burden for early satiety (p < 0.01), dizziness (p < 0.05), cough (p < 0.05) and bone pain (p < 0.01) in those receiving venesection alone. Interferon alpha was significantly associated (p < 0.05) with severe burden for 16 of the 27 symptoms. JAK2V617F-positive females experienced a greater symptom burden than JAK2V617F-positive males. There was no discernible relationship between the JAK2V617F mutation and symptom burden in MPN patients, unlike the therapeutic agents investigated. Larger studies are required to validate these results and identify mechanisms of symptom development and control in MPN patients.

Updates on accelerated and blast phase myeloproliferative neoplasms: Are we making progress?

Management approaches for accelerated and blast phase myeloproliferative neoplasms remain challenging for clinicians and patients alike. Despite many therapeutic advances, outcomes for those patients who are not allogeneic haematopoietic cell transplant eligible remain, in general, very poor. Estimated survival rates for such blast phase patients is frequently reported as less than 6 months. No specific immunological, genomic or clinicopathological signature currently exists that accurately predicts the risk and timing of transformation, which frequently induces a high degree of anxiety among patients and clinicians alike. Within this review article, we provide an up-to-date summary of current understanding of the underlying pathogenesis of accelerated and blast phase disease and discuss current therapeutic approaches and realistic outcomes. Finally, we discuss how the horizon may look with the introduction of more novel agents into the clinical arena.

Morphology of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPN) are a group of clonal haematological malignancies first described by Dameshek in 1957. The Philadelphia-negative MPN that will be described are polycythaemia vera (PV), essential thrombocythaemia (ET), pre-fibrotic myelofibrosis and primary myelofibrosis (PMF). The blood and bone marrow morphology are essential in diagnosis, for WHO classification, establishing a baseline, monitoring response to treatment and identifying changes that may indicate disease progression. The blood film changes may be in any of the cellular elements. The key bone marrow features are architecture and cellularity, relative complement of individual cell types, reticulin content and bony structure. Megakaryocytes are the most abnormal cell and key to classification, as their number, location, size and cytology are all disease-defining. Reticulin content and grade are integral to assignment of the diagnosis of myelofibrosis. Even with careful assessment of all these features, not all cases fit neatly into the diagnostic entities; there is frequent overlap reflecting the biological disease continuum rather than distinct entities. Notwithstanding this, an accurate morphologic diagnosis in MPN is crucial due to the significant differences in prognosis between different subtypes and the availability of different therapies in the era of novel agents. The distinction between "reactive" and MPN is also not always straightforward and caution needs to be exercised given the prevalence of "triple negative" MPN. Here we describe the morphology of MPN including comments on changes with disease evolution and with treatment.

Characterization of myeloproliferative neoplasms in the paediatric and young adult population

The aim of this study was to compare the genomic features and clinical outcomes between paediatric and young adult patients (PAYA, <40 years) and older adults (OA, ≥40 years) with myeloproliferative neoplasms (MPN) to gain insight into pathogenesis, disease prognosis and management. Of 630 MPN patients, 171 (27%) were PAYA with an average age at diagnosis of 31 years. Females were more prevalent in PAYA than OA (71% vs 58%; p = 0.002), and PAYA more frequently presented with essential thrombocytosis (ET) at diagnosis (67% vs 39%; p < 0.001). The presence of a JAK2 somatic mutation was higher in OA (80.4% vs 64.3%; p < 0.001), while a CALR mutation or lack of any traditional driver mutation was more common in PAYA (20.5% vs 10.5%; p = 0.001, 8.8% vs 3.7%; p = 0.01 respectively). Venous thrombosis was more common in PAYA compared to OA (19.8% vs 10.7%; p = 0.002). PAYA had a higher prevalence of familial MPN and familial cancer predisposition, and two PAYA patients harboured pathogenic germline JAK2 lesions. PAYA demonstrated longer survival from diagnosis than OA (median not reached vs 13 years), while disease transformation was less frequent (19.3% vs 37.9%).

The different variant allele frequencies of type I/type II mutations and the distinct molecular landscapes in CALR-mutant essential thrombocythaemia and primary myelofibrosis

OBJECTIVE

Calreticulin (CALR) mutations have been identified as driver mutations in a quarter of patients with essential thrombocythaemia (ET) and primary myelofibrosis (PMF), which are subgroups of myeloproliferative neoplasms (MPNs). A 52-bp deletion (type I mutation) and a 5-bp insertion (type II mutation) are the most frequent variants. To better understand the impact of different CALR mutant variants, with or without nondriver mutations, on the clinical subtypes of MPN needs further investigation.

METHODS

The clinical characteristics, laboratory parameters and genetic mutation statuses were analysed in a cohort of 77 MPN patients with CALR mutations (ET = 24, prePMF = 33, and overt PMF = 20). Targeted NGS using a 38-gene panel was performed to evaluate the variant allele frequency (VAF) of CALR type I/type II mutations and assess the molecular landscape of nondriver gene mutations.

RESULTS

A lower VAF of type I vs. type II was observed in CALR-mutant ET, prePMF and overt PMF, and a higher frequency of type I vs. type II was found in CALR-mutant overt PMF. Additional somatic mutations were indicated to be useful in understanding the pathogenesis of MPN. In this study, the mutation landscape was more complex in overt PMF than in ET or in prePMF. Mutations in epigenetic regulators (ASXL1, EZH2 and TET2) were more common in overt PMF.

CONCLUSIONS

The two different subtypes of CALR mutations may have different impacts on MPN. A lower VAF of CALR type I indicates a greater contribution to disease progression in MPN, and increased nondriver mutations may be important in myelofibrosis progression.

Skin cancer in essential thrombocythaemia and polycythaemia vera patients treated with hydroxycarbamide

Hydroxycarbamide (HC) is used as a cytoreductive treatment in myeloproliferative neoplasms (MPN). Observational studies have raised the possibility that HC contributes to the development of secondary malignancies, including skin tumours in MPN patients. In this retrospective observational study, we report a single-centre experience of 324 HC-treated MPN patients with long-term follow-up, compared to 47 MPN patients not on HC. Thirty-three patients (10.2%) (HC) versus one patient (2.1%) (no HC) developed skin tumours during follow-up (Hazard ratios [HR] 5.70, 95% confidence intervals 0.66-48.09, p = 0.112). However, male gender, age at MPN diagnosis, type of MPN (polycythaemia rubra vera) and previous history of skin cancer were prognostic variables associated with development of skin cancer.

Cytoreductive treatment and association with platelet function and maturity in patients with essential thrombocythaemia

Patients with essential thrombocythaemia (ET) have an increased risk of thromboembolic events, which may differ according to different cytoreductive drugs. We investigated the effect of cytoreductive treatment on platelet function and turnover in ET patients. Blood samples were obtained at 1 and 24 h after aspirin intake. Platelet function was evaluated by platelet aggregation and flow cytometry. Platelet turnover was assessed by immature platelet count, immature platelet fraction (IPF) and mean platelet volume (MPV). A total of 47 ET patients were included and grouped into 21 patients not receiving cytoreductive treatment, 15 patients receiving hydroxycarbamide and 11 patients receiving pegylated interferon alpha (peg‐IFN). Patients receiving peg‐IFN had significantly higher IPF and MPV than the other ET groups. Patients not receiving cytoreductive treatment had significantly higher platelet aggregation 24 h after aspirin intake than the other ET groups (p‐values from 0.03 to 0.0002). Patients receiving hydroxycarbamide had significantly higher expression of platelet granule makers, P‐selectin and CD63, than patients receiving peg‐IFN (p‐values ≤0.003). Cytoreduction provides more consistent platelet inhibition compared with no cytoreductive treatment. Moreover, peg‐IFN provides superior inhibition of platelet activation markers than hydroxycarbamide, which in part may explain differences in risk of thromboembolic events in ET patients.

Is It Possible to Predict Clonal Thrombocytosis in Triple-Negative Patients with Isolated Thrombocytosis Based Only on Clinical or Blood Findings?

JAK2, MPL, and CALR mutations define clonal thrombocytosis in about 90% of patients with sustained isolated thrombocytosis. In the remainder of patients (triple-negative patients) diagnosing clonal thrombocytosis is especially difficult due to the different underlying conditions and possible inconclusive bone marrow biopsy results. The ability to predict patients with sustained isolated thrombocytosis with a potential clonal origin has a prognostic value and warrants further examination. The aim of our study was to define a non-invasive clinical or blood parameter that could help predict clonal thrombocytosis in triple-negative patients. We studied 237 JAK2 V617-negative patients who were diagnosed with isolated thrombocytosis and referred to the haematology service. Sixteen routine clinical and blood parameters were included in the logistic regression model which was used to predict the type of thrombocytosis (reactive/clonal). Platelet count and lactate dehydrogenase (LDH) were the only statistically significant predictors of clonal thrombocytosis. The platelet count threshold for the most accurate prediction of clonal or reactive thrombocytosis was 449 × 10⁹/L. Other tested clinical and blood parameters were not statistically significant predictors of clonal thrombocytosis. The level of LDH was significantly higher in CALR-positive patients compared to CALR-negative patients. We did not identify any new clinical or blood parameters that could distinguish clonal from reactive thrombocytosis. When diagnosing clonal thrombocytosis triple-negative patients are most likely to be misdiagnosed. Treatment in patients with suspected triple negative clonal thrombocytosis should not be delayed if cardiovascular risk factors or pregnancy coexist, even in the absence of firm diagnostic criteria. In those cases the approach “better treat more than less” should be followed.

The Prevalence of TET2 Gene Mutations in Patients with BCR-ABL-Negative Myeloproliferative Neoplasms (MPN): A Systematic Review and Meta-Analysis

Multiple recurrent somatic mutations have recently been identified in association with myeloproliferative neoplasms (MPN). This meta-analysis aims to assess the pooled prevalence of TET2 gene mutations among patients with MPN. Six databases (PubMed, Scopus, ScienceDirect, Google Scholar, Web of Science and Embase) were searched for relevant studies from inception till September 2020, without language restrictions. The eligibility criteria included BCR-ABL-negative MPN adults with TET2 gene mutations. A random-effects model was used to estimate the pooled prevalence with 95% confidence intervals (CIs). Subgroup analyses explored results among different continents and countries, WHO diagnostic criteria, screening methods and types of MF. Quality assessment was undertaken using the Joanna Briggs Institute critical appraisal tool. The study was registered with PROSPERO (CRD42020212223). Thirty-five studies were included (n = 5121, 47.1% female). Overall, the pooled prevalence of TET2 gene mutations in MPN patients was 15.5% (95% CI: 12.1-19.0%, I2 = 94%). Regional differences explained a substantial amount of heterogeneity. The prevalence of TET2 gene mutations among the three subtypes PV, ET and MF were 16.8%, 9.8% and 15.7%, respectively. The quality of the included studies was determined to be moderate-high among 83% of the included studies. Among patients with BCR-ABL-negative MPN, the overall prevalence of TET2 gene mutations was 15.5%.

The Epidemiology of Myeloproliferative Neoplasms in New Zealand between 2010 and 2017: Insights from the New Zealand Cancer Registry

BACKGROUND

There is a paucity of data on ethnic disparities in patients with the classical Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs): polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF).

METHODS

This study analysed the demographic data for PV, ET and PMF collected by the New Zealand Cancer Registry (NZCR) between 2010 and 2017.

RESULTS

We found that the NZCR capture rates were lower than average international incidence rates for PV and ET, but higher for PMF (0.76, 0.99 and 0.82 per 100,000, respectively). PV patients were older and had worse outcomes than expected, which suggests these patients were reported to the registry at an advanced stage of their disease. Polynesian patients with all MPN subtypes, PV, ET and PMF, were younger than their European counterparts both at the time of diagnosis and death (p < 0.001). Male gender was an independent risk factor for mortality from PV and PMF (hazard ratios (HR) of 1.43 and 1.81, respectively; p < 0.05), and Māori ethnicity was an independent risk factor for mortality from PMF (HR: 2.94; p = 0.006).

CONCLUSIONS

New Zealand Polynesian patients may have increased genetic predisposition to MPN, thus we advocate for modern genetic testing in this ethnic group to identify the cause. Further work is also required to identify modifiable risk factors for mortality in MPN, in particular those associated with male gender and Māori ethnicity; the results may benefit all patients with MPN.

Anagrelide influences thrombotic risk, and prolongs progression-free and overall survival in essential thrombocythaemia vs hydroxyurea plus aspirin

OBJECTIVE

We report an extension study of patients with essential thrombocythaemia (ET) in the Hungarian Myeloproliferative Neoplasm (HUMYPRON) Registry, which demonstrated that over 6 years anagrelide significantly decreased the number of patients experiencing minor arterial and minor venous thrombotic events (TEs) vs hydroxyurea+aspirin.

METHODS

Data on patients with ET were collected through completion of a questionnaire developed according to 2008 WHO diagnostic criteria and with regard to Landolfi, Tefferi and IPSET criteria for thrombotic risk. Data were entered into the registry from 14 haematological centres. TEs, secondary malignancies, disease progression and survival were compared between patients with ET treated with anagrelide (n = 116) and with hydroxyurea+aspirin (n = 121).

RESULTS

Patients were followed for (median) 10 years. A between-group difference in the number of patients with TEs was observed (25.9% anagrelide vs 38.0% hydroxyurea+aspirin; P = .052). Minor arterial events were more frequently reported in the hydroxyurea+aspirin group (P < .001); there were marginally more reports of major arterial events in the anagrelide group (P = .049). TE prior to diagnosis was found to significantly influence TE incidence (P > .001). Progression-free survival (P = .004) and survival (P = .001) were significantly increased for the anagrelide group vs hydroxyurea+aspirin.

CONCLUSIONS

Anagrelide reduced TEs, and increased progression-free and overall survival vs hydroxyurea+aspirin over (median) 10 years.

Megakaryocytes, erythropoietic and granulopoietic cells express CAL2 antibody in myeloproliferative neoplasms carrying CALR gene mutations

Testing for the CALR mutation is included in the updated WHO criteria for essential thrombocythaemia (ET) and primary myelofibrosis (PMF). We report on the application of the CAL2 monoclonal antibody, raised against the mutated CALR gene to myeloid cases. The immunostain was used on 116 acute myeloid leukaemias (AML) and 66 myeloproliferative neoplasms (MPN) or myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN). None of AML cases was stained by the CAL2 antibody, while 20/66 MPNs and MDS/MPNs appeared positive. Fourteen of the latter cases were studied by molecular techniques, and all showed aberrations of the CALR gene. In addition, CAL2 positivity was found in some small‐sized elements besides megakaryocytes. By double staining, these elements corresponded to small megakaryocytes as well as both erythroid and myeloid precursors. This finding suggests possible occurrence of CALR gene abnormalities in a stem cell.

Cytoreductive treatment in patients with CALR-mutated essential thrombocythaemia: a study comparing indications and efficacy among genotypes from the Spanish Registry of Essential Thrombocythaemia

The present study assessed the criteria for initiating cytoreduction and response to conventional therapies in 1446 patients with essential thrombocythemia (ET), 267 (17%) of which were CALR-mutated. In low risk patients, time from diagnosis to cytoreduction was shorter in CALR-positive than in the other genotypes (2·8, 3·2, 7·4 and 12·5 years for CALR, MPL, JAK2V617F and TN, respectively, P < 0·0001). A total of 1104 (76%) patients received cytoreductive treatment with hydroxycarbamide (HC) (n = 977), anagrelide (n = 113), or others (n = 14). The estimated cumulative rates of complete haematological response (CR) at 12 months were 40 % and 67% in CALR and JAK2V617F genotypes, respectively. Median time to CR was 192 days for JAK2V617F, 343 for TN, 433 for MPL, and 705 for CALR genotypes (P < 0·0001). Duration of CR was shorter in CALR-mutated ET than in the remaining patients (P = 0·003). In CALR-positive patients, HC and anagrelide had similar efficacy in terms of response rates and duration. CALR-mutated patients developed resistance/intolerance to HC more frequently (5%, 23%, 27% and 15% for JAK2V617F, CALR, MPL and TN, respectively; P < 0·0001). In conclusion, conventional cytoreductive agents are less effective in CALR-mutated ET, highlighting the need for new treatment modalities and redefinition of haematologic targets for patients with this genotype.

How we manage Philadelphia-negative myeloproliferative neoplasms in pregnancy

The combined incidence of classical Philadelphia-negative myeloproliferative neoplasm (MPN) is 6-9/100 000 with a peak frequency between 50 and 70 years. MPN is less frequent in women of reproductive age. However, for essential thrombocythaemia (ET) in particular there is a second peak in women of reproductive age and 15% of polycythaemia vera (PV) patients are less than 40 years of age at the time of diagnosis. Thus these diseases are encountered in women of reproductive potential and may be diagnosed in pregnancy or in women being investigated for recurrent pregnancy loss. The incidence of MPN pregnancies is 3·2/100 000 maternities per year in the UK. The majority of data regarding Philadelphia-negative MPNs relates to patients with ET, for which the literature suggests significant maternal morbidity and poor fetal outcome; specifically maternal thrombosis and haemorrhage, miscarriage, pre-eclampsia, intrauterine growth restriction (IUGR), stillbirth and premature delivery as summarised in the recent systematic review and meta-analysis in Blood, 2018, 132, 3046. The literature for PV is more sparse but increasing and is concordant with ET pregnancy outcomes. The literature regarding primary myelofibrosis (PMF) is even more scarce. Treatment options include aspirin, venesection, low molecular weight heparin (LMWH) and cytoreductive therapy. Data and management recommendations are often extrapolated from other pro-thrombotic conditions or from ET to PV and PMF. Women of reproductive age with a diagnosis of MPN should receive information and assurance regarding management and outcome of future pregnancies. From pre-conceptual planning to the post-partum period, women should have access to joint care from an obstetrician with experience of high-risk pregnancies and a haematologist in a multidisciplinary setting. This paper provides an update with regards to Philadelphia-negative MPN in pregnancy, details local practise in an internationally recognised centre for patients with MPN and outlines a future research strategy.

Smoking, blood cells and myeloproliferative neoplasms: meta-analysis and Mendelian randomization of 2·3 million people

Meta-analyses and Mendelian randomization (MR) may clarify the associations of smoking, blood cells and myeloproliferative neoplasms (MPN). We investigated the association of smoking with blood cells in the Danish General Suburban Population Study (GESUS, n = 11 083), by meta-analyses (including GESUS) of 92 studies (n = 531 741) and MR of smoking variant CHRNA3 (rs1051730[A]) in UK Biobank, and with MPN in a meta-analysis of six studies (n (total/cases):1 425 529/2187), totalling 2 307 745 participants. In the meta-analysis the random-effects standardized mean difference (SMD) in current smokers versus non-smokers was 0·82 (0·75-0·89, P = 2·0 * 10^-108 ) for leukocytes, 0·09 (-0·02 to 0·21, P = 0·12) for erythrocytes, 0·53 (0·42-0·64, P = 8·0 * 10^-22 ) for haematocrit, 0·42 (0·34-0·51, P = 7·1 * 10^-21 ) for haemoglobin, 0·19 (0·08-0·31, P = 1·2 * 10^-3 ) for mean corpuscular haemoglobin (MCH), 0·29 (0·19-0·39, P = 1·6 * 10^-8 ) for mean corpuscular volume (MCV), and 0·04 (-0·04 to 0·13, P = 0·34) for platelets with trends for ever/ex-/current smokers, light/heavy smokers and female/male smokers. Analyses presented high heterogeneity but low publication bias. Per allele in CHRNA3, cigarettes per day in current smokers was associated with increased blood cell counts (leukocytes, neutrophils), MCH, red cell distribution width (RDW) and MCV. The pooled fixed-effects odds ratio for MPN was 1·44 [95% confidence interval (CI): 1·33-1·56; P = 1·8 * 10^-19 ; I²  = 0%] in current smokers, 1·29 (1·15-1·44; P = 8·0 * 10^-6 ; I²  = 0%) in ex-smokers, 1·49 (1·26-1·77; P = 4·4 * 10^-6 ; I²  = 0%) in light smokers and 2·04 (1·74-2·39, P = 2·3 * 10^-18 ; I²  = 51%) in heavy smokers compared with non-smokers. Smoking is observationally and genetically associated with increased leukocyte counts and red blood cell indices (MCH, MCV, RDW) and observationally with risk of MPN in current and ex-smokers versus non/never-smokers.

Molecular heterogeneity unravelled by single-cell transcriptomics in patients with essential thrombocythaemia

Significant phenotypic heterogeneity exists in patients with all subtypes of myeloproliferative neoplasms (MPN), including essential thrombocythaemia (ET). Single-cell RNA sequencing (scRNA-Seq) holds the promise of unravelling the biology of MPN at an unprecedented level of resolution. Herein we employed this approach to dissect the transcriptomes in the CD34⁺ cells from the peripheral blood of seven previously untreated ET patients and one healthy adult. The mutational profiles in these patients were as follows: JAK2 V617F in two, CALR in three (one type I and two type II) and triple-negative (TN) in two. Our results reveal substantial heterogeneity within this enrolled cohort of patients. Activation of JAK/STAT signalling was recognized in discrepant progenitor lineages among different samples. Significantly disparate molecular profiling was identified in the comparison between ET patients and the control, between patients with different driver mutations (JAK2 V617F and CALR exon 9 indel), and even between patients harbouring the same driver. Intra-individual clonal diversity was also found in the CD34⁺ progenitor population of a patient, possibly indicating the presence of multiple clones in this case. Estimation of subpopulation size based on cellular immunophenotyping suggested differentiation bias in all analysed samples. Furthermore, combining the transcriptomic information with data from targeted sequencing enabled us to unravel key somatic mutations that are molecularly relevant. To conclude, we demonstrated that scRNA-Seq extended our knowledge of clonal diversity and inter-individual heterogeneity in patients with ET. The obtained information could potentially leapfrog our efforts in the elucidation of the pathogenesis of the disease.

Essential thrombocythaemia treated with recombinant interferon: 'real world' United Kingdom referral centre experience

Standard first-line therapy choice for essential thrombocythaemia (ET) requiring cytoreduction, supported by randomized trials, is low-dose aspirin with hydroxycarbamide, but the role of recombinant interferon-alfa (IFNα)-2a/2b and pegylated (PEG)-IFN-α-2a/2b is increasingly highlighted. Longer-term outcome data, however, remains somewhat scarce, particularly in the 'real world'. We hereby report on a large, well-annotated cohort of ET patients from a single referral centre undergoing therapy with either IFNα or (PEG)-IFN-α-2a/2b and demonstrate high rates of complete haematological responses, good tolerability and safety, low rates of thromboembolic events in compliant patients and confirm feasibility of long-term therapy in a significant proportion of patients.

A phase III randomized, multicentre, double blind, active controlled trial to compare the efficacy and safety of two different anagrelide formulations in patients with essential thrombocythaemia - the TEAM-ET 2·0 trial

Anagrelide is an established treatment option for essential thrombocythaemia (ET). A prolonged release formulation was developed with the aim of reducing dosing frequency and improving tolerability, without diminishing efficacy. This multicentre, randomized, double blind, active‐controlled, non‐inferiority trial investigated the efficacy, safety and tolerability of anagrelide prolonged release (A‐PR) over a reference product in high‐risk ET patients, either anagrelide‐naïve or ‐experienced. In a 6 to 12‐week titration period the individual dose for the consecutive 4‐week maintenance period was identified. The primary endpoint was the mean platelet count during the maintenance period (3 consecutive measurements, day 0, 14, 28). Of 112 included patients 106 were randomized. The mean screening platelet counts were 822 × 10⁹/l (95% confidence interval (CI) 707–936 × 10⁹/l) and 797 × 10⁹/l (95% CI 708–883 × 10⁹/l) for A‐PR and the reference product, respectively. Both treatments effectively reduced platelet counts, to mean 281 × 10⁹/l for A‐PR (95% CI 254–311) and 305 × 10⁹/l (95% CI 276–337) for the reference product (P < 0·0001, for non‐inferiority). Safety and tolerability were comparable between both drugs. The novel prolonged‐release formulation was equally effective and well tolerated compared to the reference product. A‐PR provides a more convenient dosing schedule and will offer an alternative to licensed immediate‐release anagrelide formulations.

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.

A rare vascular complication in a patient with essential thrombocythaemia: spontaneous abdominal aortic dissection

A 27-year-old woman complained of waist and back pain. Abdominal computed tomography angiography showed abdominal aortic dissection, the blood count revealed a high platelet count of 1655 × 10⁹ /L. Negative for JAK2V617F, CALR and MPL mutations (i.e. triple-negative), the patient was diagnosed as essential thrombocythaemia (ET) with abdominal aortic dissection and was treated with cytoreduction and antiplatelet drugs. Cases of abdominal aortic dissection in ET have not been previously reported. As such, we proposed a mechanism of abdominal aortic dissection caused by endothelial dysfunction and further emphasised appropriate management in ET with abdominal aortic dissection.

[Epidemiologic features of Philadelphia-negative chronic myeloproliferative disorders in Szabolcs-Szatmár-Bereg county, Hungary. Analysis of data of a 33-year period]

INTRODUCTION

In their previous work, the authors reported findings from 30 years on the incidence of hematological malignancies in Szabolcs-Szatmár-Bereg county, Hungary. Until now there are no other studies on this topic available in Hungary.

AIM

Detailed analysis of epidemiologic features of patients with Philadelphia-negative chronic myeloproliferative disorders was carried out.

METHOD

During a 33-year period (between January 1, 1983 and December 31, 2015) 4523 adult patients with hematologic malignancies were recorded in the leukaemia/lymphoma registry of Szabolcs-Szatmár-Bereg county. Among them, 255 patients with polycytaemia vera, 102 with primary myelofibrosis, and 331 with essential thrombocytaemia were registered.

RESULTS

The incidence of polycythaemia vera and essential thrombocythaemia in Szabolcs-Szatmár-Bereg county showed an increasing tendency, with an overall incidence rate of 1.35 and 1.75/100 000 inhabitants/year, respectively; while the incidence of primary myelofibrosis decreased in the course of years (0.54/100 000 inhabitants/year). In cases of polycythaemia vera and primary myelofibrosis the male:female ratio was found to be equal, however essential thrombocythaemia showed a female dominance. The mean age of patients with polycythaemia vera was 65 (21-95) years, similar to essential thrombocythaemia with 65 (19-85) years, and to primary myelofibrosis with 65.5 (33-84) years. There were only two villages found in this county where the occurrence of patients with Philadelphia-negative chronic myeloproliferative disorders per one thousand inhabitants was significantly higher, than the average (1.22). In every familial cases of these, the manifestation of the disease in the second and the third generations became earlier than in the first genetration. The perceived average degree of the anteposition (anticipation) was found to be 22 years.

CONCLUSION

The epidemiologic features of Philadelphia-negative chronic myeloproliferative disorders in Szabolcs-Szatmár-Bereg county are essentially similar to data published in the literature. Orv. Hetil., 2017, 158(15), 572-578.

[An audit of the Hungarian Philadelphia negative chronic myeloproliferative neoplasia registry. Evaluation of the essential thrombocythaemic patients]

INTRODUCTION

In order to establish and use a national registry, several Hungarian hematology centers collected data of myeloproliferative neoplasia patients.

AIM

The recent publication is an analysis of the data of registered essential thrombocythaemic patients.

METHOD

an online electronic registry has been established, using 2008 World Health Organization's diagnostic criteria and thrombotic risk was evaluated according to Landolfi stratification.

RESULTS

Data of 350 essential thrombocythaemic patients from 15 Hungarian hematology centers entered up to the date of June 30, 2015 were used for analysis. Patients were followed up to (median) 6 years. The epidemiologic data (age, gender) and thrombotic events prior and after the diagnosis, were similar to the literature. The thrombotic events of anagrelide treated patient (n = 139) and the hydroxyurea + aspirin treated patients (n = 141) have been compared. The major arterial and venous events were similar between the groups, but there were fivefold less minor arterial and venous events in the anagrelide group (p<0.001). Thrombotic incidence after diagnosis were influenced only by medication and thrombotic events before the diagnosis.

CONCLUSIONS

Anagrelide significantly decreased the number of patients experiencing minor arterial and minor venous thrombosis, vs hydroxyurea + aspirin. Despite of the treatment the risk of thrombotic events after diagnosis remained high, and was significantly increased in patients with thrombosis before diagnosis. Orv. Hetil., 2017, 158(3), 111-116.

Investigation of T-cell immunoglobulin- and mucin-domain-containing molecule-3 (TIM-3) polymorphisms in essential thrombocythaemia (ET)

OBJECTIVES

T-cell immunoglobulin- and mucin-domain-containing molecule-3 (TIM-3) is preferentially expressed on terminally differentiated Th1 cells and inhibits their IFN-γ production. It has been reported that chronic inflammation may be an important driving force for myeloproliferative neoplasms (MPNs). Therefore, we hypothesized that as an important inflammation regulator, TIM-3 may be involved in essential thrombocythaemia (ET). The goal of this study was to investigate whether the -1516G > T, -574G > T and +4259T > G single-nucleotide polymorphisms (SNPs) within the TIM-3 gene contribute to the genetic susceptibility of individuals to ET.

METHODS

Genotyping of the TIM-3 -1516G > T, -574G > T and + 4259T > G SNPs was performed in 175 patients with ET and in 151 controls via a polymerase chain reaction-restriction fragment length polymorphism assay. We also investigated the relationships between the genotypes of each SNP and the risk factors of ET such as routine blood indexes, age and JAK2 V617F mutation.

RESULTS

The genotype and allele frequencies of the -1516G > T SNP (p = 0.016 and 0.019, respectively), the -574G > T SNP (p = 0.035 and 0.038, respectively) and the +4259T > G SNP (p = 0.036 and 0.038, respectively) of the ET patients and the controls were significantly different. A haplotype analysis found that the GGT and TGT haplotypes had significantly different distributions between ET and controls (p = 0.041 and 0.041, respectively). However, no significant differences were detected between the genotypes of all SNPs and routine blood indexes, age and JAK2V617F mutation.

CONCLUSION

The -1516G > T, -574G > T and +4259T > G SNPs within TIM-3 gene might play an important role as a genetic risk factor in the pathogenesis of ET.

hydroxyurea plus aspirin

OBJECTIVE

To evaluate the reduction in thrombotic events (TE) in patients with essential thrombocythaemia (ET) treated with anagrelide versus hydroxyurea + aspirin (HU + ASA).

METHODS

A questionnaire was developed using 2008 WHO diagnostic criteria, and thrombotic risk factors were stratified according to Landolfi criteria. Through questionnaire completion, clinicians at Hungarian haematological centres entered data into the Hungarian MPN Registry on patients with myeloproliferative neoplasms. Based on ET registry data, TEs in anagrelide-treated patients (n = 139) were compared with HU + ASA-treated patients (n = 141).

RESULTS

Patients were followed up for (median) 6 yr. TEs were reported in significantly fewer anagrelide-treated patients versus HU + ASA (15.1% versus 49.6%; P < 0.001). Numbers of major arterial and major venous events were similar between the groups, although there were over fivefold more minor arterial and minor venous events in the HU + ASA group (P < 0.001). While median age at diagnosis was older and length of follow-up shorter in the HU + ASA group (P < 0.05), this did not influence TE incidence; medication and TE before diagnosis only influenced TE incidence.

CONCLUSIONS

Anagrelide significantly decreased the number of patients experiencing minor arterial and minor venous TEs versus HU + ASA over 6 yr. Risk of TE after diagnosis was significantly increased if the patient had TE before diagnosis.

Pregnancy outcomes in myeloproliferative neoplasms: UK prospective cohort study

The reported higher risk of maternal and fetal complications in women with myeloproliferative neoplasms (MPN) poses challenge during pregnancy. A national prospective study of maternal and fetal outcomes of pregnant women with a diagnosis of MPN was undertaken via the United Kingdom Obstetric Surveillance System between January 2010 and December 2012. Fifty-eight women with a diagnosis of MPN were identified; 47 (81%) essential thrombocythaemia, five (9%) polycythaemia vera, five (9%) myelofibrosis and one (2%) MPN-unclassified. There were 58 live births. The incidence of miscarriage was 1·7/100 (95% confidence interval [CI]: 0·04-9·24) and the perinatal mortality rate was 17/1000 (95% CI: 0·44-92·36) live and stillbirths. Incidence of maternal complications was 9% (5/57) pre-eclampsia, 9% (5/57) post-partum haemorrhage and 3·5% (2/57) post-partum haematoma. There were no maternal deaths or thrombotic events. Delivery was induced in 45% (24/53) of women and the Caesarean section rate was 45% (24/53). The majority (85%, 45/53) delivered at term (>37 weeks gestation). Twenty-two percent (12/54) of neonates were below the 10% centile for growth and 13% (7/54) required admission to a neonatal care-unit; there were no neonatal deaths. The findings of this large, UK prospective study suggests women with MPN appear to have successful pregnancies with better outcomes than would be anticipated from the literature.

Interferon alpha-2b for Essential Thrombocythaemia: Results in 13 Previously Untreated Patients

Interferon alpha-2b (αIF) was administered to 13 previously untreated patients with essential thrombocythaemia (ET). Pretreatment median platelet count was 1.178 (range, 662 to 1,700) x 10(9)/L, with ten patients showing values above 1,000 × 10(9)/L. Six patients had vascular symptoms attributable to ET, whereas in the remaining cases treatment was instituted due to either an increased vascular risk or platelet counts higher than 1,000 × 10(9)/L. With an induction regimen of αIF 3 MU/day, given subcutaneously, a rapid decrease in the platelet counts was observed in all cases. Two patients did not complete the induction therapy because of unacceptable toxic side-effects at the time their platelet counts approached normal values. In the remaining 11 patients a complete haematologic response (platelets below 400 × 10(9)/L) was observed, after a median of 9.5 (range, 2.6 to 36) weeks from the start of therapy. In only 3 patients was dose escalation of interferon to 5 MU/day required. Eleven patients experienced flu-like symptoms, that could be well controlled by oral paracetamol in 7 cases. After discontinuing therapy a rise in the platelet counts was observed in all patients, after a median of 5 (range, 2 to 35) weeks. Two patients subsequently refused to continue on interferon therapy, whereas in the remainder a dose of 3 MU 2 to 4 times weekly maintained normal platelet counts.

Application of an NGS-based 28-gene panel in myeloproliferative neoplasms reveals distinct mutation patterns in essential thrombocythaemia, primary myelofibrosis and polycythaemia vera

Molecular routine diagnostics for BCR-ABL1-negative myeloproliferative neoplasms (MPN) currently focusses on mutations in JAK2, CALR and MPL. In recent years, recurrent mutations in MPNs have been identified in several other genes. We here present the validation of a next generation sequencing (NGS)-based 28-gene panel and its use in MPN. We analysed the mutation status of 28 genes in 100 MPN patients [40 essential thrombocythaemia (ET), 30 primary myelofibrosis (PMF), 30 polycythaemia vera (PV)] and found two or more mutated genes in 53 patients. Moreover, significantly more mutated splicing genes (SF3B1, SRSF2 and U2AF1) were present in PMF (0·60 mutated genes/patient) compared to ET (0·15) while no mutations in splicing genes were found in PV. Additionally, chromatin modification genes (ASXL1 and EZH2) were frequently mutated in PMF patients (0·50) and, to a significantly lesser extent, in ET (0·13) and PV (0·07). Contrarily, DNA methylation genes (DNMT3A, IDH1, IDH2 and TET2) were mutated most often in PV (0·5) and less frequently in ET (0·23) and PMF (0·20), but without reaching statistical significance. Our results demonstrate the feasibility and utility of NGS-based panel diagnostics for MPN. With 53% of the patients bearing two or more mutated genes, their prognostic relevance needs further studies.

Long-term outcome of liver transplant patients with Budd-Chiari syndrome secondary to myeloproliferative neoplasms

BACKGROUND

A considerable proportion of patients receiving liver transplants for Budd-Chiari syndrome (BCS) suffer from myeloproliferative neoplasms (MPN). This study evaluated the long-term prognosis of liver-transplanted patients with BCS secondary to MPN and the effect of immunosuppression on MPN progression.

METHODS

A total of 78 patients with BCS were evaluated between 1982 and 2013. Of those, 40 patients suffered from polycythaemia vera (PV) and essential thrombocythaemia (ET). One patient had primary myelofibrosis (PMF). All patients received the standard immunosuppressive regimen. We retrospectively evaluated the long-term survival, clinical course and laboratory parameters of patients with MPN.

RESULTS

Exactly 29/41 patients (71%) with MPN survived ≥ 3 years [mean age 36 ± 11 years; females n = 27 (93%)]. Mean follow-up after orthotopic liver transplantation (OLT) was 12.4 ± 7.3 years (range 3-28 years). Five- and 10-year survival rates were not significantly different in patients with and without MPN (P = 0.81 and P = 0.66 respectively) or in patients with PV and ET (P = 0.29 and P = 0.55 respectively). Thrombosis and bleeding developed in 7/29 (24%) long-term MPN survivors with no significant difference between ET and PV (P = 0.18). In the long-term follow-up, there was no evidence of progression to overt myelofibrosis or acute myeloid leukaemia (AML). In the uni- and multivariate Cox-regression analyses, MPN did not influence survival after OLT.

CONCLUSIONS

Budd-Chiari syndrome patients with and without underlying MPN had similar long-term survival rates after OLT. There was no evidence of enhanced progression of MPN after OLT secondary to immunosuppressive therapy. However, major haemorrhage and recurrent thrombosis contributed to morbidity and mortality after OLT in those patients.

[Thrombotic events and significance of the IPSET thrombosis risk evaluation score in essential thrombocythaemia]

INTRODUCTION

Thrombo-haemorrhagic complications contribute to both morbidity and mortality in patients with essential thrombocythaemia.

AIM

The aim of the authors was to estimate the incidence of thrombotic events and to examine the clinical utility of IPSET thrombosis risk evaluation score against conventional two-categorical (low and high) risk assessment.

METHOD

A retrospective analysis was carried out on 155 patients with essential thrombocythaemia (106 females; median age, 61 years) in a period between 1999 and 2014.

RESULTS

The analysis revealed 55 (35.5%) major thrombotic events before and 25 (16.1%) major thrombotic complications after establishment of the haematologic diagnosis. Significant differences were observed in thrombosis-free survival between the different IPSET groups (p = 0.002).

CONCLUSIONS

The IPSET model was first examined in this cohort of patients with essential thrombocythaemia diagnosed in a single Hungarian haematologic centre. The results suggest that this score may provide more information than the conventional thrombosis risk assessment.

Are all cases of paediatric essential thrombocythaemia really myeloproliferative neoplasms? Analysis of a large cohort

Sporadic essential thrombocythaemia (ET) is rare in paediatrics, and the diagnostic and clinical approach to paediatric cases cannot be simply copied from experience with adults. Here, we assessed 89 children with a clinical diagnosis of ET and found that 23 patients (25·8%) had a clonal disease. The JAK2 V617F mutation was identified in 14 children, 1 child had the MPL W515L mutation, and 6 had CALR mutations. The monoclonal X-chromosome inactivation pattern was seen in six patients (two with JAK2 V617F and two with CALR mutations). The other 66 patients (74·2%) had persistent thrombocytosis with no clonality. There were no clinical or haematological differences between the clonal and non-clonal patients. The relative proportion of ET-specific mutations in the clonal children was much the same as in adults. The higher prevalence of non-clonal cases suggests that some patients may not have myeloproliferative neoplasms, with significant implications for their treatment.

Dysregulation of the MIRLET7/HMGA2 axis with methylation of the CDKN2A promoter in myeloproliferative neoplasms

Overexpression of high mobility group AT-hook 2 (Hmga2), which is negatively regulated by MIRLET7 micro RNAs through 3'-untranslated region (3'UTR), causes proliferative haematopoiesis mimicking myeloproliferative neoplasms (MPNs) and contributes to progression of myelofibrosis in mice. Thus, we investigated HMGA2 mRNA expression in 66 patients with MPNs including 23 polycythaemia vera (PV), 33 essential thrombocythaemia (ET) and 10 primary myelofibrosis (PMF). HMGA2 mRNA expression, especially variant 1 with 3'UTR that contains MIRLET7-specific sites, rather than variant 2 lacking 3'UTR, is frequently deregulated due to decreased MIRLET7 expression in granulocytes from over 20% of PV and ET, and in either granulocytes or CD34(+) cells from 100% of PMF. Patients with deregulated HMGA2 mRNA expression were significantly more likely to show splenomegaly, high serum lactate dehydrogenase values, and methylation of the CDKN2A promoter compared with other patients without deregulation of HMGA2. A histone deacetylase inhibitor, panobinostat, significantly increased MIRLET7 expression and reduced variant 1 of HMGA2 mRNA expression, but not variant 2, in both U937 cells and PMF-derived CD34(+) cells. Moreover, both panobinostat and small interfering RNA of HMGA2 demethylated the CDKN2A promoter in U937 cells. In conclusion, the frequently dysregulated MIRLET7/HMGA2 axis could be a therapeutic target in MPNs.

A lower intensity of treatment may underlie the increased risk of thrombosis in young patients with masked polycythaemia vera

In patients who do not meet the World Health Organization (WHO) criteria for overt polycythaemia vera (PV), a diagnosis of masked PV (mPV) can be determined. A fraction of mPV patients may display thrombocytosis, thus mimicking essential thrombocythaemia (ET). No previous studies have examined clinical outcomes of mPV among young JAK2-mutated patients. We analysed a retrospective cohort of 538 JAK2-mutated patients younger than 40 years, after a re-assessment of the diagnosis according to the haemoglobin threshold for mPV. In this cohort of patients, 97 (18%) met the WHO criteria for PV, 66 patients (12%) were classified as mPV and 375 (70%) as JAK2-mutated ET. Surprisingly, a significant difference in the incidence of thrombosis was found when comparing mPV versus overt PV patients (P = 0·04). In multivariate analysis, the only factor accounting for the difference in the risk of thrombosis was the less frequent use of phlebotomies and cytoreduction in mPV patients compared to those with overt PV. Thus, we emphasize the need for the identification of mPV in young JAK2-mutated patients in order to optimize their treatments.

In vivo prostacyclin biosynthesis and effects of different aspirin regimens in patients with essential thrombocythaemia

Essential thrombocythaemia (ET) is characterised by enhanced platelet generation and thrombosis. Once daily (od) aspirin incompletely inhibits platelet thromboxane (TX)A2 production in ET. A twice daily (bid) dosing is necessary to fully inhibit TXA2. Whether this dosing regimen affects in vivo prostacyclin (PGI2) biosynthesis is unknown. PGI2 biosynthesis was characterised in 50 ET patients on enteric-coated (EC) aspirin 100 mg od, by measuring its urinary metabolite, 2,3-dinor-6-keto-PGF1α (PGI-M). Moreover, in a crossover study 22 patients poorly responsive to standard aspirin based on serum TXB2 levels (≥4 ng/ml) were randomised to different seven-day aspirin regimens: EC aspirin 100 mg od, 100 mg bid, 200 mg od, or plain aspirin 100 mg od. PGI-M measured 24 hours after the last aspirin intake (EC, 100 mg od) was similar in patients and healthy subjects both on (n=10) and off (n=30) aspirin. PGI-M was unrelated to in vivo TXA2 biosynthesis, and not affected by EC aspirin 100 mg bid or 200 mg od as compared to EC 100 mg od. PGI2 biosynthesis in aspirin-treated ET patients appears unrelated to TXA2 biosynthesis, and not affected by an improved aspirin regimen, demonstrating its vascular safety for future trials.

[Incidence of haematological malignancies in adults in Szabolcs-Szatmár-Bereg county, Hungary, between 1983 and 2012. Analysis of data from a thirty-year period]

INTRODUCTION

In their previous work the authors reported 25 years' findings on the incidence of haematological malignancies in Szabolcs-Szatmár-Bereg county, Hungary. However, there are no other studies on this topic available in Hungary.

AIM

The aim of the authors was to analyze the incidence of malignant haematological disorders between 1983 and 2012 using data obtained from the leukaemia/lymphoma registry of the Szabolcs-Szatmár-Bereg county.

METHOD

Between January 1, 1983 and December 31, 2012, 3964 adult patients with newly diagnosed haematological malignancy were recorded in the registry. Patients with myelodysplastic syndrome or monoclonal gammopathy were not registered.

RESULTS

The annual number of newly diagnosed patients indicated an increasing tendency of malignant haematological disorders. The increase was primarily due to the increasing number of patients with non-Hodgkin's lymphoma, chronic lymphocytic leukaemia, and essential thrombocythaemia.

CONCLUSIONS

These observations are in line with data reported in the international literature. The incidence rate of haematological malignancies in this region of Hungary was similar to data published in populations from Western European countries and the United States.

Paediatric essential thrombocythaemia: clinical and molecular features, diagnosis and treatment

The incidence of essential thrombocythaemia (ET) in children (age ≤18 years) is extremely low. The natural course of the disorder in children has not been clarified. The rarity of patients and the variability of tested parameters make it difficult to draw any definitive conclusion in pathogenesis and diagnosis of paediatric ET. What makes the onset of thrombocytosis earlier in children is still uncertain. A diagnostic algorithm for paediatric ET has not been established, and current risk stratification used to guide therapeutic decisions in adults has not been validated in children. Vascular complications and transformation to myelofibrosis and leukaemia in this special entity have been reported, suggesting that ET in children is not an entirely benign disease. The crucial question is how to identify patients who are at high risk of complications and need treatment. There are insufficient data to recommend a specific agent in children. The purpose of this review is to outline the most recent progress in paediatric ET and to help with understanding the clinical course, molecular features, diagnosis and treatment strategies in this special group.