The management of myelofibrosis: a British Society for Haematology guideline

This document represents an update of the British Society for Haematology guideline on Myelofibrosis first published in 2012 and updated in 2015 These guidelines aim to pro-vide healthcare professionals with clear guidance on stratified management for primary myelofibrosis (PMF), as well as post-polycythaemia myelofibrosis (post-PV MF) and postessential thrombocythaemia myelofibrosis (post-ET MF). A separate BSH guideline covers the diagnosis and prognostic evaluation of myelofibrosis and is published alongside this guideline

Serum JAK/STAT profile is related to the IL expression but not with the outcome in pancreatic adenocarcinoma patients.

Current genetic characterization of pancreatic ductal adenocarcinoma (PDAC) does not integrate the host reaction to cancer cells and cannot predict the response to chemo- or immunotherapy. The JAK/STAT pathway is an important factor of cytokine-mediated cancer inflammation, but its relationship with pancreatic carcinogenesis and the role of potential biomarkers is not established yet. Our study aimed to assess the significance of serum levels of JAK/STAT3 expression and inflammatory cytokines in PDAC in relation to the clinicopathological features and prognosis. This prospective cohort study included patients with proven adenocarcinoma and a matched group of controls without any malignancies. There were evaluated the serum expression of IL2, 6, 8, 17, JAK2, and STAT3 by ELISA assays in these two groups. The PDAC patients were followed up for 24 months. A Cox regression multivariate analysis model was used to determine factors influencing survival. The study comprised 56 patients with PDAC and 56 controls. The upregulated serum JAK2/STAT3 or cytokines were present in about half of the patients with PDAC, similar to controls. The expression of JAK2 in serum of PDAC patients was significantly associated with the expression of IL2 (p=0.03) and IL6 (p=0.02) but not with survival or metastasis development. Only age and the presence of lymph node metastases were associated with reduced survival in multivariate analyses. The STAT 3/JAK2 expression, although correlated with inflammatory status (IL2, IL6) was not overexpressed in PDAC compared to controls and proved no prognostic value.

Is there a gender effect in polycythemia vera?

In recent times, there has been a growing interest in understanding the impact of gender on disease biology and clinical outcomes in Philadelphia-negative chronic myeloproliferative neoplasms. Among those, polycythemia vera (PV) is characterized by increased thrombotic risk, systemic symptoms, and overall reduced survival. Here, we aim to summarize data on whether and to what extent female sex can affect PV biology and outcome. To this end, we will discuss the latest acquisitions in terms of pathogenesis, diagnosis, epidemiology, clinical presentation and symptoms burden, thrombotic risk and related treatment strategies, and prognosis in female patients affected by PV.

Platelet Dysfunction and Thrombosis in JAK2V617F-Mutated Primary Myelofibrotic Mice.

OBJECTIVE: The risk of thrombosis in myeloproliferative neoplasms, such as primary myelofibrosis varies depending on the type of key driving mutation (JAK2 [janus kinase 2], CALR [calreticulin], and MPL [myeloproliferative leukemia protein or thrombopoietin receptor]) and the accompanying mutations in other genes. In the current study, we sought to examine the propensity for thrombosis, as well as platelet activation properties in a mouse model of primary myelofibrosis induced by JAK2V617F (janus kinase 2 with valine to phenylalanine substitution on codon 617) mutation. Approach and Results: Vav1-hJAK2V617F transgenic mice show hallmarks of primary myelofibrosis, including significant megakaryocytosis and bone marrow fibrosis, with a moderate increase in red blood cells and platelet number. This mouse model was used to study responses to 2 models of vascular injury and to investigate platelet properties. Platelets derived from the mutated mice have reduced aggregation in response to collagen, reduced thrombus formation and thrombus size, as demonstrated using laser-induced or FeCl3-induced vascular injury models, and increased bleeding time. Strikingly, the mutated platelets had a significantly reduced number of dense granules, which could explain impaired ADP secretion upon platelet activation, and a diminished second wave of activation. CONCLUSIONS: Together, our study highlights for the first time the influence of a hyperactive JAK2 on platelet activation-induced ADP secretion and dense granule homeostasis, with consequent effects on platelet activation properties.

Global dynamics of healthy and cancer cells competing in the hematopoietic system.

Stem cells in the bone marrow differentiate to ultimately become mature, functioning blood cells through a tightly regulated process (hematopoiesis) including a stem cell niche interaction and feedback through the immune system. Mutations in a hematopoietic stem cell can create a cancer stem cell leading to a less controlled production of malfunctioning cells in the hematopoietic system. This was mathematically modelled by Andersen et al. (2017) including the dynamic variables: healthy and cancer stem cells and mature cells, dead cells and an immune system response. Here, we apply a quasi steady state approximation to this model to construct a two dimensional model with four algebraic equations denoted the simple cancitis model. The two dynamic variables are the clinically available quantities JAK2V617F allele burden and the number of white blood cells. The simple cancitis model represents the original model very well. Complete phase space analysis of the simple cancitis model is performed, including proving the existence and location of globally attracting steady states. Hence, parameter values from compartments of stem cells, mature cells and immune cells are directly linked to disease and treatment prognosis, showing the crucial importance of early intervention. The simple cancitis model allows for a complete analysis of the long term evolution of trajectories. In particular, the value of the self renewal of the hematopoietic stem cells divided by the self renewal of the cancer stem cells is found to be an important diagnostic marker and perturbing this parameter value at intervention allows the model to reproduce clinical data. Treatment at low cancer cell numbers allows returning to healthy blood production while the same intervention at a later disease stage can lead to eradication of healthy blood producing cells. Assuming the total number of white blood cells is constant in the early cancer phase while the allele burden increases, a one dimensional model is suggested and explicitly solved, including parameters from all original compartments. The solution explicitly shows that exogenous inflammation promotes blood cancer when cancer stem cells reproduce more efficiently than hematopoietic stem cells.

Myeloproliferative Diseases as Possible Risk Factor for Development of Chronic Thromboembolic Pulmonary Hypertension-A Genetic Study.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease which is often caused by recurrent emboli. These are also frequently found in patients with myeloproliferative diseases. While myeloproliferative diseases can be caused by gene defects, the genetic predisposition to CTEPH is largely unexplored. Therefore, the objective of this study was to analyse these genes and further genes involved in pulmonary hypertension in CTEPH patients. A systematic screening was conducted for pathogenic variants using a gene panel based on next generation sequencing. CTEPH was diagnosed according to current guidelines. In this study, out of 40 CTEPH patients 4 (10%) carried pathogenic variants. One patient had a nonsense variant (c.2071A>T p.Lys691*) in the BMPR2 gene and three further patients carried the same pathogenic variant (missense variant, c.1849G>T p.Val617Phe) in the Janus kinase 2 (JAK2) gene. The latter led to a myeloproliferative disease in each patient. The prevalence of this JAK2 variant was significantly higher than expected (p < 0.0001). CTEPH patients may have a genetic predisposition more often than previously thought. The predisposition for myeloproliferative diseases could be an additional risk factor for CTEPH development. Thus, clinical screening for myeloproliferative diseases and genetic testing may be considered also for CTEPH patients.

JAK-STAT Activity in Peripheral Blood Cells and Kidney Tissue in IgA Nephropathy.

BACKGROUND AND OBJECTIVES: IgA nephropathy is the most common primary glomerular disease in the world. Marked by mesangial inflammation and proliferation, it generally leads to progressive kidney fibrosis. As the Janus kinase signal transducer and activator of transcription pathway has been implicated as an important mediator of diabetic kidney disease and FSGS, detailed investigation of this pathway in IgA nephropathy was undertaken to establish the basis for targeting this pathway across glomerular diseases. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Well characterized patients with IgA nephropathy and controls were studied, allowing us to compare 77 patients with biopsy-proven IgA nephropathy with 45 healthy subjects. STAT phosphorylation was assessed in peripheral blood monocytes (PBMCs) by phosphoflow before and after cytokine stimulation. Kidney Janus kinase signal transducer and activator of transcription activity was studied by immunofluorescence and by transcriptomic studies. An STAT1 activity score was established using downstream transcriptional targets of pSTAT1 and associated with disease and clinical outcomes. RESULTS: We found PBMCs to have upregulated pSTAT production at baseline in patients with IgA nephropathy with a limited reserve to respond to cytokine stimulation compared with controls. Increased staining in glomerular mesangium and endothelium was seen for Jak-2 and pSTAT1 and in the tubulointerstitial for JAK2, pSTAT1, and pSTAT3. Activation of the Janus kinase signal transducer and activator of transcription pathway was further supported by increased pSTAT1 and pSTAT3 scores in glomerular and tubulointerstitial sections of the kidney (glomerular activation Z scores: 7.1 and 4.5, respectively; P values: <0.001 and <0.001, respectively). Clinically, phosphoflow results associated with proteinuria and kidney function, and STAT1 activation associated with proteinuria but was not associated with progression. CONCLUSIONS: Janus kinase signal transducer and activator of transcription signaling was activated in patients with IgA nephropathy compared with controls. There were altered responses in peripheral immune cells and increased message and activated proteins in the kidney. These changes variably related to proteinuria and kidney function.

Rho kinase cascade activation in circulating leukocytes in patients with diabetes mellitus type 2.

BACKGROUND: The intracellular ROCK signaling pathway is an important modulator of blood pressure and of cardiovascular and renal remodeling when Rho-kinase activity is increased. Besides, in preclinical models of diabetes, ROCK activation has also a role in abnormal glucose metabolism as well as in subsequent vascular and myocardial dysfunction. In humans, there are a few data assessing ROCK activation in patients with type 2 diabetes mellitus (T2D) and no studies assessing upstream/downstream components of the ROCK pathway. We assessed here levels of ROCK activation and some of the RhoA/ROCK cascade molecules in peripheral blood mononuclear cells (PBMCs) in T2D patients under current treatment. METHODS: Cross-sectional observational study comparing 28 T2D patients under current antidiabetic treatment with 31 consecutive healthy subjects, matched by age and gender. Circulating levels of malondialdehyde, angiotensin II and inflammatory cytokines IL-6 and IL-8 were determined in all subjects. ROCK activation in PMBCs, upstream and downstream cascade proteins, and levels of the proinflammatory molecules VCAM, ICAM-1 and IL-8 were determined in their PMBCs by Western blot. RESULTS: Compared to healthy controls, ROCK activation in T2D patients measured by 2 direct ROCK targets in PBMCs was increased by 420 and 570% (p < 0001) and it correlated significantly with serum glucose levels. p38 MAPK phosphorylation (downstream from ROCK) and JAK-2 (upstream from ROCK) were significantly higher in the T2D patients by 580% and 220%, respectively. In T2D patients, significantly increased PBMC levels of the proinflammatory molecules VCAM-1, ICAM-1 and IL-8 were observed compared to control subjects (by 180%, 360% and 260%, respectively). Circulating levels of Ang II and MDA were significantly higher in T2D patients by 29 and 63%, respectively. CONCLUSIONS: T2D patients under treatment with glucose-lowering drugs, antihypertensive treatment as well as with statins have significantly increased ROCK activation in their circulating leukocytes along with higher phosphorylation of downstream cascade proteins despite pharmacologic treatment, along with increased plasma angiotensin II and MDA levels. ROCK inhibition might have an additional role in the prevention and treatment of T2D.

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

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

Beyond Hemoglobin: When and How to Work Up Possible Polycythemia Vera.

BACKGROUND: World Health Organization (WHO) 2017 diagnostic criteria for hemoglobin levels in polycythemia vera (PV) were lowered from 185 g/L to 165 g/L for men and from 165 g/L to 160 g/L for women, but these cutoffs were not designed for screening. OBJECTIVES: The primary aim of this study was to assess the value of laboratory and clinical parameters in deciding whether to further pursue a diagnosis of PV. A secondary aim was to explore the diagnostic utility of bone marrow morphology. METHODS: We evaluated clinical and laboratory parameters that may be useful when considering further diagnostic work-up, emphasizing PV vs. secondary erythrocytosis (SE). We classified 200 patients with JAK2 V617F testing using WHO criteria. RESULTS: Patients with myeloproliferative neoplasms (MPN) were rarely under age 40 and uncommonly obese (BMI ≥ 30 kg/m2). Current smoking history favored SE, and these patients rarely had a platelet count ≥ 450 × 103/uL. Laboratory parameters suggesting greater PV likelihood were: RBC > 6.8 × 106 for men or > 5.9 × 106 for women; low erythropoietin; and low MCV or low ferritin. Bone marrow morphology (available in 111 cases) was generally more cellular in PV vs. SE and assessed disease progression. CONCLUSIONS: Readily accessible clinical and laboratory data can assist in considering a PV workup, and a possible diagnostic algorithm is presented. These preliminary findings warrant larger studies to develop a more formal PV-risk scoring system with optimal cutoffs and weighting.

JAK2 V617F-positive essential thrombocythemia with subsequent development of immune thrombocytopenia: A case report.

RATIONALE: Although essential thrombocythemia (ET) and immune thrombocytopenia (ITP) have different etiologies, 3 previous reports have described ET development in ITP patients, all of whom were positive for the JAK2 V617F mutation. Here, we report the first published case of ITP following ET in the absence of other platelet disorders. PATIENT CONCERNS: A 70-year-old woman with a five-year history of ET with JAK2 V617F mutation treated with hydroxycarbamide for five months presented with petechiae on her limbs. DIAGNOSIS: Her platelet count was 3 × 10/L, with the immature platelet fraction being 29%. White blood cell count and hemoglobin level were normal. Bone marrow examination showed increased number of megakaryocytes, but no morphologic dysplasia in any lineage. G-band analysis revealed no abnormalities. Platelet transfusion and cessation of hydroxycarbamide did not affect the platelet count. Thrombocytopenia was unlikely to have been induced by drugs, heparin, systemic lupus erythematosus, or human immunodeficiency virus. Hence, a diagnosis of ITP was made. INTERVENTIONS: The patient received oral prednisolone combined with intravenous immunoglobulin. OUTCOMES: Her platelet count rose to 310 × 10/L and remained stable, while her steroid dose was reduced. Further blood tests revealed the presence of antibodies against Helicobacter pylori, and appropriate treatment was administered. Resumption of hydroxycarbamide did not induce thrombocytopenia. LESSONS: Although ET and ITP have different etiologies, chronic inflammation and immune deregulation underlie both and may play an important role in the progression from one to the other. Further research is warranted to understand the relationship between ET and ITP.

Physical proximity and functional cooperation of glycoprotein 130 and glycoprotein VI in platelet membrane lipid rafts.

OBJECTIVE: Clinical and laboratory studies have demonstrated that platelets become hyperactive and prothrombotic in conditions of inflammation. We have previously shown that the proinflammatory cytokine interleukin (IL)-6 forms a complex with soluble IL-6 receptor α (sIL-6Rα) to prime platelets for activation by subthreshold concentrations of collagen. Upon being stimulated with collagen, the transcription factor signal transducer and activator of transcription (STAT) 3 in platelets is phosphorylated and dimerized to act as a protein scaffold to facilitate the catalytic action between the kinase Syk and the substrate phospholipase Cγ2 (PLCγ2) in collagen-induced signaling. However, it remains unknown how collagen induces phosphorylation and dimerization of STAT3. METHODS AND RESULTS: We conducted complementary in vitro experiments to show that the IL-6 receptor subunit glycoprotein 130 (GP130) was in physical proximity to the collagen receptor glycoprotein VI (GPVI in membrane lipid rafts of platelets. This proximity allows collagen to induce STAT3 activation and dimerization, and the IL-6-sIL-6Rα complex to activate the kinase Syk and the substrate PLCγ2 in the GPVI signal pathway, resulting in an enhanced platelet response to collagen. Disrupting lipid rafts or blocking GP130-Janus tyrosine kinase (JAK)-STAT3 signaling abolished the cross-activation and reduced platelet reactivity to collagen. CONCLUSION: These results demonstrate cross-talk between collagen and IL-6 signal pathways. This cross-talk could potentially provide a novel mechanism for inflammation-induced platelet hyperactivity, so the IL-6-GP130-JAK-STAT3 pathway has been identified as a potential target to block this hyperactivity.

Algorithmic evaluation of hereditary erythrocytosis: Pathways and caveats.

Multiple algorithms have been published for the evaluation of hereditary erythrocytosis (HE). Typical entry points begin after excluding the more common acquired conditions through investigations of clinical history and assessment of cardiac, pulmonary, or vascular system disorders. Prior exclusion of JAK2 mutations, particularly the common JAK2 V617F mutation, is indicated in adults but less so in pediatric populations. Key decision trees are based on serum erythropoietin levels and p50 results. Recent data reveal some overlap in clinical presentation and laboratory findings in erythrocytosis. Caveats to consider when using algorithmic approaches are discussed.

Discovery and evaluation of ZT55, a novel highly-selective tyrosine kinase inhibitor of JAK2V617F against myeloproliferative neoplasms.

BACKGROUND: The JAK2-STAT signaling pathway plays a critical role in myeloproliferative neoplasms (MPN). An activating mutation in JAK2 (V617F) is present in ~ 95% of polycythemia vera, essential thrombocythemia, and primary myelofibrosis cases. This study aims to explore the selective JAK2V617F inhibitor, evaluate the efficacy and possible mechanism of ZT55 on MPN. METHODS: HTRF assays were conducted to evaluate the selective inhibition of ZT55 for JAKs. Cell apoptosis, proliferation, and cycle arrest assays were performed to examine the effect of ZT55 on HEL cell line with JAK2V617F mutation in vitro. Western analysis was used to monitor the expression and activity of proteins on JAK2/STAT pathway. A mice xenograft model was established to evaluate the antitumor efficacy of ZT55 in vivo. Peripheral blood samples from patients with the JAK2V617F mutation were collected to estimate the effect of ZT55 on erythroid colony formation by colony-forming assay. RESULTS: We found that ZT55 showed a selective inhibition of a 0.031 µM IC50 value against JAK2. It exhibited potent effects on the cellular JAK-STAT pathway, inhibiting tyrosine phosphorylation in JAK2V617F and downstream STAT3/5 transcription factors. ZT55 inhibited the proliferation of the JAK2V617F-expressing HEL cell line, leading to cell cycle arrest at the G2/M phase and induction of caspase-dependent apoptosis. Notably, ZT55 also significantly suppressed the growth of HEL xenograft tumors in vivo. Further evaluation indicated that ZT55 blocked erythroid colony formation of peripheral blood hematopoietic progenitors from patients carrying the JAK2V617F mutation. CONCLUSION: These results suggest that ZT55 is a highly-selective JAK2 inhibitor that can induce apoptosis of human erythroleukemia cells by inhibiting the JAK2-STAT signaling.

Total flavonoids extracted from Nervilia Fordii function in polycystic ovary syndrome through IL-6 mediated JAK2/STAT3 signaling pathway.

Large doses of flavonoids could cure many diseases with no serious side effects. However, the role of flavonoids in the treatment of polycystic ovary syndrome (PCOS) has not been reported. Therefore, total flavonoids extracted from Nervilia Fordii were selected to explore its therapeutic efficiency in PCOS. PCOS rat model was constructed to explore the role of total flavonoids in the treatment of PCOS. ELISA was used to assess the changes of ovulation function under the treatment of total flavonoids with or without exogenous interleukin-6 (IL-6). Western blot, real-time PCR and immunohistochemistry were carried out to assess the related molecular mechanisms. We explored that total flavonoids obviously increased the serum levels of follicle-stimulating hormone (FSH), and sharply decreased the serum levels of luteinizing hormone (LH), testosterone (T) and insulin (INS) in the PCOS-IR rats via partly inhibiting the activation of JAK2/STAT3 pathway, partially up-regulating the IL-6 expression and partially down-regulating the suppressor of cytokine signaling 3 (SOCS3) expression in ovaries of PCOS rats. The effect of total flavonoids on estrous cycles, serum levels of FSH, LH, T and INS were partially attenuated by IL-6 in PCOS rat model. Moreover, IL-6 significantly reversed the effect of total flavonoids on the phosphorylation of JAK2/STAT3, the expression of IL-6 and SOCS3 in ovaries of PCOS rats. Total flavonoids extracted from Nervilia Fordii might induce the expression of IL-6 in ovary and act as a potential therapeutic drug for the treatment of PCOS.

JAK-STAT signaling is activated in the kidney and peripheral blood cells of patients with focal segmental glomerulosclerosis.

Focal segmental glomerular sclerosis (FSGS) is a devastating disease with limited treatment options and poor prognosis. Activated JAK-STAT signaling has been implicated in other kidney diseases. Since new technologies allow us to better evaluate changes in systemic and renal JAK-STAT activity as it relates to kidney function, we examined this in 106 patients with biopsy-proven FSGS compared to 47 healthy control individuals. Peripheral immune function was assessed in peripheral blood mononuclear cells by phosphoflow studies before and after cytokine stimulation. Kidney JAK-STAT activity was measured by immunofluorescence and by transcriptomics. A STAT1 activity score was calculated by evaluating message status of downstream targets of pSTAT 1. Peripheral blood mononuclear cells were found to be upregulated in terms of pSTAT production at baseline in FSGS and to have limited reserve to respond to various cytokines. Increased staining for components of the JAK-STAT system in FSGS by microscopy was found. Furthermore, we found transcriptomic evidence for activation of JAK-STAT that increased pSTAT 1 and pSTAT 3 in glomerular and tubulointerstitial sections of the kidney. Some of these changes were associated with the likelihood of remission of proteinuria and progression of disease. JAK-STAT signaling is altered in patients with FSGS as compared to healthy controls with activated peripheral immune cells, increased message in the kidney and increased activated proteins in the kidney. Thus, our findings support immune activation in this disease and point to the JAK-STAT pathway as a potential target for treatment of FSGS.

A comparison of qPCR and ddPCR used for quantification of the JAK2 V617F allele burden in Ph negative MPNs.

Philadelphia-negative myeloproliferative neoplasms (MPNs) are a diverse group of diseases whose common feature is the presence of V617F mutation of the JAK2 gene. In the era of novel therapeutic strategies in MPNs, such as JAK-inhibitor therapy, there is a growing need for establishing high sensitive quantitative methods, which can be useful not only at diagnosis but also for monitoring therapeutic outcomes, such as minimal residual disease (MRD). In this study, we compared the qPCR and ddPCR methods and their clinical utility for diagnosis, prognostication, and treatment monitoring of MPNs with JAK2 V617F mutation in 63 MPN patients of which 6 were subjected to ruxolitinib treatment. We show a high conformance between the two methods (correlation coefficient r = 0.998 (p < 0.0001)). Our experiments revealed high analytical sensitivity for both tests, suggesting that they are capable of detecting the JAK2 V617F mutation at diagnosis of MPN with a limit of detection (LoD) of 0.12% for qPCR and 0.01% for ddPCR. The alterations of JAK2 V617F allele burden in patients treated with ruxolitinib were measured by both methods with equal accuracy. The results suggest an advantage of ddPCR in monitoring MRD because of allele burdens below the LoD of qPCR. Overall, the clinical utility of qPCR and ddPCR is very high, and both methods could be recommended for the routine detection of the V617F mutation at diagnosis, though ddPCR will probably supersede qPCR in the future due to cost-effectiveness.

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.

Neutropenia caused by hairy cell leukemia in a patient with myelofibrosis secondary to polycythemia vera: a case report.

BACKGROUND: Polycythemia vera is a myeloproliferative disease that sometimes evolves to myelofibrosis, causing splenomegaly and neutropenia. In this case report, we describe a patient with polycythemia vera and unexplained neutropenia who later turned out to also have hairy cell leukemia. CASE PRESENTATION: A middle-aged Caucasian man with polycythemia vera presented to our hospital with chronic mouth ulcers. Later he developed leukopenia and pancytopenia. Bone marrow biopsies showed fibrosis. Further morphological analyses of bone marrow and blood smears revealed probable transformation into acute myeloid leukemia. However, there were also cells indicating hairy cell leukemia. Morphological and immunohistochemical analyses later confirmed the presence of hairy cell leukemia in biopsies that had been present for 3 years. Treatment with cladribine temporarily reversed the patient's neutropenia. CONCLUSIONS: Hairy cell leukemia may mimic development to myelofibrosis in patients with polycythemia vera.