Cultivation of Megakaryocytes On a Collagen Matrix: A More Sensitive and Reproducible Test for the Diagnosis of Patients with Essential Thrombocythaemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4970-4970
Author(s):  
Adrian Emanuel Schmidt ◽  
Patricia Darlington ◽  
Lucie Kopfstein ◽  
Elisabeth Ischi ◽  
Elisabeth Oppliger Leibundgut ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Platelet Count ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Healthy Subjects ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Essential Thrombocythaemia ◽  
Jak2 Mutation ◽  
Spontaneous Proliferation

Abstract Abstract 4970 Background Essential thrombocythaemia (ET) is one of the chronic myeloproliferative neoplasms (MPN), along with polycythaemia vera (PV), primary myelofibrosis (PMF) and chronic myeloid leukaemia (CML). Their common feature is excessive proliferation of a certain stem or progenitor cell in the bone marrow; in the case of ET, the megakaryocytic lineage is affected. Clinical manifestations include thrombotic events and haemorrhage. Diagnosis of ET according to new WHO-criteria requires a sustained high platelet count, bone marrow biopsy showing proliferation of the megakaryocytic lineage with large and mature morphology, demonstration of JAK2 V617F (although only present in about 50% of patients with ET) or another clonal marker and explicit exclusion of other myeloid and myeloproliferative neoplasms as well as signs of reactive thrombocytosis. Additionally, spontaneous proliferation of megakaryocytes obtained from peripheral blood can be detected in in vitro culture assays. Presently, we use agar as a matrix for megakaryocyte cultivation, although this assay has never been validated in connection with ET. The identification of megakaryocytic colonies grown on agar can sometimes be quite difficult. Our aims were therefore to technically evaluate the use of a collagen based matrix and to investigate its suitability to identify patients with ET. Patients and Methods We have examined 63 patients (26 with ET, 21 with PV, 8 with myelofibrosis [MF; including PMF and post-ET/PV-MF], 6 with secondary or idiopathic erythrocytosis and 2 with secondary thrombocytosis; mean age=59.8, male=33, female=30, mean platelet count 457 G/l) and 5 healthy subjects. Following informed consent, both clinical and laboratory data was collected. Medication intake, phlebotomies, smoking habits and regular haemogram results were noted in order to recognise possible confounding factors influencing laboratory results. Results of megakaryocyte cultivation on both agar and collagen matrixes were recorded, considering both spontaneous growth and growth stimulated by megakaryocyte derived growth factor (MDGF). Results Based on our collagen culture results we were able to define 2 or more spontaneously grown megakaryocyte colonies as the most optimal cut-off for the identification of patients with MPN (sensitivity 71%, specificity 100% with positive and negative predictive values of 100% and 45%, respectively). Compared to the agar culture results (where a specificity and a positive predictive value of 100% were demonstrated at a cut-off value of ≥ 10 CFU-Mega) we found a higher accuracy and better reproducibility. In addition, we observed an improved negative predictive value (45% with collagen versus 25% with agar cultures) reducing false negative results. Healthy subjects and patients with secondary thrombocytosis showed no significant spontaneous megakaryocyte proliferation. In patients with MF, we observed strong spontaneous and MDGF-stimulated growth of megakaryocytic colonies. At a cut-off value of ≥ 50 CFU-Mega (after stimulation with MDGF), the collagen assay showed a sensitivity of 100% and a specifity of 70% for this special form of MPN, resulting in a negative predictive value of 100%. We found no confounding clinical or laboratory parameters such as medication intake (particularly cytoreductive treatment with hydroxyurea) or phlebotomies influencing our culture results, and no significant effect of the Jak2-V617F mutation on the growth behaviour of megakaryocytic colonies. Conclusion The results of this ongoing study imply that the collagen based assay is more sensitive, specific, time efficient and user friendly regarding the detection of spontaneous proliferation of megakaryocytes than the currently used agar based culture assay. In addition, the collagen based assay also has the great advantage that it allows isolation of single megakaryocytic colonies for further analyses, for example PCR-based identification of a JAK2 mutation. Furthermore, the collagen based assay facilitates the diagnosis of patients with MPN, especially in cases where conventional diagnostic criteria are lacking, such as in ET without a JAK2 mutation. Ultimately, the new assay may well be able to detect transformation from PV/ET to MF. Disclosures No relevant conflicts of interest to declare.

A Novel Mutation in MPL (Y252H) Results in Increased Thrombopoietin Sensitivity and Moderate Thrombocytosis in a Pediatric Patient with Essential Thrombocytosis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2817-2817
Author(s):  
Michele Lambert ◽  
Jing Jiang ◽  
Wei Tong
Keyword(s):  
Bone Marrow ◽  
Platelet Count ◽  
Bone Marrow Cells ◽  
Novel Mutation ◽  
Missense Variant ◽  
Jak2 V617f ◽  
Jak2 Mutation ◽  
Hematopoietic Malignancies ◽  
Healthy Control ◽  
Pediatric Populations

Abstract Abstract 2817 Myeproliferative neoplams (MPNs) constitute a group of hematopoietic malignancies that feature enhanced proliferation and/or survival of one or more myeloid lineage cells, including Essential Thrombocythemia (ET). MPN development is rare in children with an estimated annual incidence of ET of 0.09/106 children. The WHO defines ET as persistent platelet count >600 k/mcL in the absence of known cause of reactive/secondary thrombocytosis. The JAK2 V617F mutation is most commonly reported in both children and adults with ET although the reported frequency varies in pediatric populations from 0 to 36% of patients. Mutations in the thrombopoietin receptor (TPO receptor or MPL) intracellular domain, specifically W515K/L, have also been reported in both adult and pediatric ET patients. Here we report a novel mutation in the MPL extracellular domain, Y252H, causing mild thrombocytosis. The patient presented at 2 years of age with a platelet count of 765 k/mcL. During the 3-year follow-up period, she possessed platelet counts between 600–700k/mcL, without any obvious indication of reactive/secondary thrombocytosis. Because of the persistently increased platelet count, her bone marrow was evaluated and it demonstrated increased numbers of megakaryocytes with focal clustering. JAK2 mutation analysis was negative and cytogenetics did not show any clonal abnormalities. Sequencing of the MPL gene showed a missense variant at c.754 T>C resulting in a tyr252his amino acid substitution. To investigate if this Y252H mutation in MPL dysregulates TPO/MPL- mediated cell growth, we introduced it into cytokine-dependent BaF3 cells. Cells stably expressing the mutant MPL allele showed increased proliferation to TPO, in particular at low concentration, in comparison to cells expressing wildtype (WT) MPL. Upon cytokine withdrawal, BaF3 cells expressing the MPL Y252H mutant survived better than that of WT MPL. Primary bone marrow cells from this patient along with the healthy control were subjected to colony forming unit -megakaryocyte (CFU-meg) assays in response to a serial dose of TPO. The Y252H MPL bone marrow showed significantly increased megakaryocyte colonies at low dose of TPO when compared to control bone marrow (17.5 ± 2.5 colonies versus 4.75 ± 1.1 colonies at 15 ng/mL TPO, p<0.001). These results are consistent with the clinically mild thrombocytosis. In summary, our results suggest a novel MPL mutation, Y252H, results in pediatric ET. Further evaluation of the mechanisms of increased TPO sensitivity imparted by this mutation should contribute to our understanding of the molecular pathogenesis of ET. Disclosures: Lambert: Cangene: Honoraria.

Anagrelid In Essential Thrombocythaemia Treatment of a Patient Under 12 Months

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4680-4680
Author(s):  
Pawel Laguna ◽  
Michal Romiszewski ◽  
Anna Klukowska ◽  
Katarzyna Pawelec ◽  
Michal Matysiak
Keyword(s):  
Bone Marrow ◽  
Platelet Count ◽  
Conflicts Of Interest ◽  
Jak2 V617f ◽  
Essential Thrombocythaemia ◽  
Biochemical Tests ◽  
Results Of Treatment ◽  
Life Threatening ◽  
Laboratory Investigations ◽  
Chronic Myeloproliferative Disorder

Abstract Abstract 4680 Essential thrombocythaemia (ET) is a chronic myeloproliferative disorder. It occurs mostly in adults and rarely in young children. We present the case of ET in an 8 –month- old girl, who was treated with Anagrelid for 13 months. The girl was admitted to the hospital because of elevated platelet count. She had stomach pains periodically. On admission the child's condition was good but on palpation her stomach was sore and her spleen was enlarged. Laboratory investigations showed an elevated platelet count (1.5m) and hypercalaemia (6.3mEq/l). Thrombopoetin was normal. Acesan was added to the treatment. A morphology performed after 1 month revealed further elevation of platelets (up to 2.65m). On the basis of the laboratory investigations, bone-marrow biopsy and trepanobiopsy, we eliminated an oncological disease and infectious diseases of connective tissues. On bone-marrow investigation, acquired mutation of JAK2 (V617F) tyrosine kinase was diagnosed, which confirmed ET. On account of the growing number of platelets, which was life - threatening, we decided to administer Anagrelid, starting with a dose of 0.25 mg per day. The number of platelets decreased to 1.4m, so the dose was increased to 0,25 mg twice daily after 3 weeks. At present, after 13 months of Anagrelid treatment, the number of platelets in the child ranges between 400 and 650. The patient comes to our, department for monthly check-up of morphology, biochemical tests, ECG and echocardiography. In international literature there is no information on the use of Anagrelid in ET treatment of children under 12 months old. However, on the basis of our observations and initial results of treatment, it seems that the above protocol for Anagrelid administration is safe for infants of this age. Disclosures: No relevant conflicts of interest to declare.

Thrombocytosis and essential thrombocythaemia

2020 ◽  
pp. 5239-5247
Author(s):  
Daniel Aruch ◽  
Ronald Hoffman
Keyword(s):  
Platelet Count ◽  
Myeloproliferative Neoplasms ◽  
Receptor Gene ◽  
Jak2 V617f ◽  
Prior History ◽  
Polycythaemia Vera ◽  
Essential Thrombocythaemia ◽  
Minor Criterion ◽  
History Of ◽  
The One

The term thrombocytosis refers to a platelet count elevated above 450 × 109/litre, which can be (1) primary—including essential thrombocythaemia, chronic myeloid leukaemia, polycythaemia vera, and myelodysplastic syndromes; or (2) secondary—including iron deficiency, infection, blood loss, and malignancy. Essential thrombocythaemia: aetiology—the JAK2 V617F missense mutation typical of polycythaemia vera is found in about 50% of cases. In addition, 10% of patients have a mutation in the thrombopoietin receptor gene, MPL, and 30% have a mutation in calreticulin (CALR). Approximately 10% of patients have none of these mutations and are referred to as ‘triple negative’ essential thrombocythaemia. Diagnosis requires all of the following four major criteria: (1) platelet count greater than 450 × 109/litre; (2) bone marrow biopsy showing proliferation mainly of the megakaryocyte lineage with increased numbers of enlarged, mature megakaryocytes with hyperlobulated nuclei without a significant increase or left shift in neutrophil granulopoiesis or erythropoiesis and very rarely minor (grade 1) increase in reticulin fibres; (3) failure to meet the criteria for other myeloproliferative neoplasms; and (4) presence of JAK2, CALR, or MPL mutations. Alternatively, diagnosis can be met when the first three major criteria are present and the one minor criterion, namely the presence of another clonal marker or absence of evidence for reactive thrombocytosis. Treatment requires risk stratification based on the age of the patient and any prior history of thrombosis, with treatment being reserved for those at a high risk of developing complications and not introduced simply on the basis of platelet counts alone unless there is extreme thrombocytosis (>1500 × 109/litre). Therapies include low-dose aspirin and cytoreduction.

The JAK2 V617F Mutation Identifies Specific Subgroups of Myelodysplastic Syndrome (MDS).

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2610-2610
Author(s):  
M. Mansour Ceesay ◽  
Nicholas Lea ◽  
Wendy C. Ingram ◽  
Jose Cervera ◽  
Ulrich Germing ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Platelet Count ◽  
Peripheral Blood ◽  
White Cell Count ◽  
Jak2 V617f ◽  
Wild Type ◽  
Refractory Anaemia ◽  
Jak2 Mutation ◽  
Specific Pcr ◽  
Cell Fractions

Abstract The myelodysplastic syndromes (MDS) encompass a heterogeneous group of clonal stem cell disorders characterised by ineffective erythropoiesis and peripheral blood cytopenias. However, specific subgroups of MDS with both myeloproliferative (MPD) and dysplastic features are recognized, which include chronic myelomonocytic leukaemia (CMML), refractory anaemia with ringed sideroblasts and thrombocytosis (RARS-T) and MDS/MPD unclassified. In addition cases of 5q- syndrome may present with a marked elevation in platelet count and a hypercellular bone marrow. The molecular events which determine the predominant morphological features however remain unclear. The JAK2 somatic point mutation (V617F) results in constitutive activation of the tyrosine kinase and culminates in both proliferation and differentiation signals to the cell and thus may contribute to the proliferative features identified in MDS as reported in the chronic MPDs. We analysed 194 patients from six centres with a diagnosis of MDS or MDS/MPD for the presence of the JAK2 mutation. 11 cases of RA; 70, RARS; 60, 5q- syndrome; 28, refractory anaemia with excess blasts (RAEB); 9, acute myeloid leukaemia with multi-lineage dysplasia (AML-MLD); 4, MDS/MPD-U; 1, CMML; and 1, hypoplastic MDS were analysed. DNA samples were obtained from bone marrow aspirate or peripheral blood. Ethical approval was obtained. Genomic DNA was prepared using standard methods (Qiagen). A modified allele specific PCR (AS PCR) was used to screen DNA samples. JAK2 mutated DNA samples were further subjected to pyrosequencing for confirmatory testing. The median age of the JAK2 mutant versus wild type (WT) cases was 66years (46–80years) v 67years (30–92years). The JAK2 mutation was detected in 13/194 (6.7%) cases overall. 4/70 (5.7%) RARS, 5/60 (8%) 5q- syndrome, 1/28 RAEB (associated with del 5q), 1/4 CMML, 1 MDS/MPD-U and 1/8 AML-MLD demonstrated the mutation. Within the RARS cohort, the prevalence of JAK2 mutation increased to 4/6 (67%) of cases with thrombocytosis (platelets >500x109/l). The presence of the mutation was confirmed in 8/13 cases. In cases analysed, the mutation was detected in CD34+, CD14+, CD15+ and CD61+ cell fractions but not CD3+ or CD19+ cell lineages. On analysis of the haemoglobin (Hb), platelet count and total white cell count (WCC) in the JAK2 mutant versus wild-type groups, there was no difference in median Hb (10.8 v 9.2 g/dl, p=0.275) but a significantly higher median platelet count (526 v 209 x109/l, p<0.001) and WCC (6.43 v 4.84x109/l, P<0.001) was observed in the JAK2 mutant cases. In addition, all JAK2 mutant cases were associated with marked increase in bone marrow cellularity. The JAK2 mutation identifies a subset of MDS patients with proliferative bone marrow morphology and frequent thrombocytosis and leucocytosis. The presence of JAK2 mutation helps to identify a subgroup of MDS patients who may benefit from therapies that specifically target the mutant JAK2.

Abstract 12726: Crucial Role of Jak2 V617f-positive Myeloproliferative Neoplasm in the Development of Aortic Aneurysm

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Tetsuro Yokokawa ◽  
Tomofumi Misaka ◽  
Yusuke KIMISHIMA ◽  
Kento Wada ◽  
Keiji Minakawa ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Angiotensin Ii ◽  
Aortic Aneurysm ◽  
Mrna Expression ◽  
Abdominal Aorta ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Vascular Complication ◽  
The Impact

Objective: To investigate the impact of hematopoietic JAK2V617F, which causes myeloproliferative neoplasms (MPNs), on the development of aortic aneurysm (AA). Approach and Results: We applied a bone marrow transplantation (BMT) strategy using the donor cells from Jak2 V617F transgenic (JAK2 V617F ) mice into the lethally irradiated apolipoprotein E-deficient mice. To induce the AA formation and progression, the recipient mice (BMT mice) were subjected to continuous angiotensin II infusion. Abdominal aortic diameter in JAK2 V617F -BMT mice was significantly enlarged compared to the control wild-type (WT)-BMT mice in response to angiotensin II. The incidence of abdominal AA was significantly higher in JAK2 V617F -BMT mice than in WT-BMT mice. Hematopoietic JAK2V617F accelerated aortic elastic lamina degradation as well as activation of matrix metalloproteinase (MMP)-2 and MMP-9 in the abdominal aorta. The numbers of CD68 + macrophages and Ly6B.2 + neutrophils and cytokine expressions such as Ccl6 and Tgfb1 were significantly increased in the abdominal aorta of JAK2 V617F -BMT mice accompanied by STAT3 activation. Bone marrow-derived macrophages carrying JAK2V617F showed elevations of both Mmp2 and Mmp9 mRNA expression. Finally, we found that 23% of MPN patients with JAK2 V617F mutation showed the presence of AA and increases in TGFB3 and IL-8 mRNA expression of the peripheral leukocytes. Conclusions: Hematopoietic JAK2V617F was involved in the development of AA through increases in the infiltration of inflammatory cells and MMP activation. Our findings provide a novel feature of vascular complication of AA in MPNs due to constitutive activation of the hematopoietic JAK-STAT pathway.

scholarly journals Thrombocytapheresis in Patient with Essential Thrombocythemia: A Case Report

2020 ◽  
Vol 13 (2) ◽  
pp. 675-679
Author(s):  
Afra M. Elhassan ◽  
Arwa Alsaud ◽  
Mohamed A. Yassin ◽  
Mahmood Aldapt ◽  
Lubna Riaz ◽  
...  
Keyword(s):  
Platelet Count ◽  
Case Report ◽  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Favorable Outcome ◽  
Who Criteria ◽  
Icu Admission ◽  
Calr Mutation ◽  
Clonal Abnormalities

Essential thrombocythemia (ET) is one of the myeloproliferative neoplasms, characterized by persistent thrombocytosis, platelets >450,000/μL, and evident clonal abnormalities like JAK2 V617F, MPL, CALR mutation and not fulfilling WHO criteria for MDS, CML, PV, and IDA. Here we report a 24-year-old female who presented with headache and was found to have thrombocytosis with a platelet count of 2,141 × 103/μL, diagnosed as ET as per WHO criteria 2008; she required ICU admission and thrombocytapheresis with a favorable outcome.

Identification of oncostatin M as a JAK2 V617F‐dependent amplifier of cytokine production and bone marrow remodeling in myeloproliferative neoplasms

2011 ◽  
Vol 26 (2) ◽  
pp. 894-906 ◽  
Author(s):  
Gregor Hoermann ◽  
Sabine Cerny‐Reiterer ◽  
Harald Herrmann ◽  
Katharina Blatt ◽  
Martin Bilban ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cytokine Production ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Oncostatin M

Direct Activation of STAT5 by TEL-Lyn Fusion Protein Promotes Induction of Myeloproliferative Neoplasms with Myelofibrosis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4114-4114
Author(s):  
Yusuke Takeda ◽  
Chiaki Nakaseko ◽  
Hiroaki Tanaka ◽  
Masahiro Takeuchi ◽  
Makiko Yui ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Signaling Molecules ◽  
Janus Kinase ◽  
Idiopathic Myelofibrosis ◽  
Lyn Kinase

Abstract Abstract 4114 Background Myeloproliferative neoplasms (MPN), a group of hematopoietic stem cell (HSC) disorders, are often accompanied by myelofibrosis. The V617F somatic mutation in the Janus kinase 2 (JAK2) gene has recently been found in the majority of patients with polycythemia vera (PV) and more than half of patients with essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF). The expression of JAK2 V617F causes a PV-like disease with myelofibrosis in a murine bone marrow (BM) transplant model. In addition, a gain-of-function c-MPL W515 mutation was described in nearly 10% of patients with JAK2 V617F-negative IMF. However, the mechanism responsible for MPD and the formation of myelofibrosis in patients without JAK2 or c-MPL mutations is still unclear. We previously identified the fusion of the TEL gene to the Lyn gene (TEL-Lyn) in idiopathic myelofibrosis with ins(12;8)(p13;q11q21). The introduction of TEL-Lyn into HSCs resulted in fatal MPN with massive myelofibrosis in mice, implicating the rearranged Lyn kinase in the pathogenesis of MPN with myelofibrosis. However, the signaling molecules directly downstream from and activated by TEL-Lyn remain unknown. Design and Methods We examined the signaling pathways activated by TEL-Lyn by Western blotting, immunoprecipitation, and in vitro kinase assay using a TEL-Lyn kinase-dead mutant as a control. We further characterized the functional properties of Stat5-deficient HSCs transduced with TEL-Lyn by colony-forming assay and bone marrow transplantation to evaluate the role of STAT5 in TEL-Lyn-induced MPN. Results TEL-Lyn was demonstrated to be constitutively active as a kinase through autophosphorylation. In TEL-Lyn-expressing cells, STAT5, STAT3, and Akt were constitutively activated. Among these signaling molecules, STAT5 was activated most prominently and this occurred without the activation of Jak2, the major kinase for STAT5. TEL-Lyn was co-immunoprecipitated with STAT5, and STAT5 was phosphorylated when incubated with TEL-Lyn, but not with TEL-Lyn kinase-dead mutant. These results indicate that TEL-Lyn interacts with STAT5 and directly activates STAT5 both in vitro and in vivo. Of note, the capacity of TEL-Lyn to support the formation of hematopoietic colonies under cytokine-free conditions in vitro and to induce MPN with myelofibrosis in vivo was profoundly attenuated in a Stat5-null background. Conclusions In this study, we clearly showed that TEL-Lyn directly activates STAT5 and the capacity of TEL-Lyn to induce MPN with myelofibrosis was profoundly attenuated in the absence of STAT5. Our findings of TEL-Lyn in this study support the role of the Src family kinases in the regulation of STAT pathways and implicate active Lyn in the alternative pathway for STAT activation in pathological cytokine signaling. Our mouse model of MPD with myelofibrosis would be beneficial for the analysis of therapeutic approaches for myelofibrosis. Disclosures: No relevant conflicts of interest to declare.

First Achievements of MPN&MPNr-EuroNet (COST Action BM0902), a New European Network Dedicated to the Diagnosis of Myeloproliferative Neoplasms and Hereditary Erythrocytosis and Thrombocytosis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2809-2809
Author(s):  
Sylvie Hermouet ◽  
Eric Lippert ◽  
Niels Pallisgaard ◽  
Jiri Schwarz ◽  
Mary Frances McMullin ◽  
...  
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Hereditary Diseases ◽  
Diagnostic Tools ◽  
Training School ◽  
Scientific Cooperation ◽  
Jak2 Mutation ◽  
Cost Action ◽  
New Genes ◽  
Training Schools

Abstract Abstract 2809 Background: The MPN&MPNr-EuroNet network, created in November 2009, is supported by the European program COST (CoOperation in Science and Technology). It is open to all colleagues active in the fields of myeloprolifeative neoplasms (MPN) and related hereditary diseases (MPNr: hereditary erythrocytosis and thrombocytosis). AIMS: To facilitate, improve and innovate in the diagnosis of MPN and hereditary erythrocytosis and thrombocytosis in Europe. Methods: MPN&MPNr-EuroNet has formed 4 working groups (WG): WG 1 focuses on JAK2 -mutated MPN; WG 2 is dedicated to thrombocythemia and myelofibroses without mutation of JAK2 and includes subgroups specialized in hereditary thrombocytosis (HT) and in histopathology; WG 3 is dedicated to hereditary erythrocytosis (HE); WG 4 is responsible for scientific cooperation and the diffusion of scientific knowledge. Results: During the first 18 months of MPN&MPNr-EuroNet activity, 77 colleagues from 19 countries (16 European countries plus Israel, Turkey, and the USA), joined the network and participated in the four WG, resulting in the achievements listed below. WG 1: 1) determination of the best JAK2 V617F assays, a joint MPN&MPNr-EuroNet/European LeukemiaNet project; 2) on-going study of MPN cases with low JAK2 V617F burden; 3) on-going study of MPN cases with multiple JAK2 mutation. WG 2: 1) list of laboratories responsible for the diagnosis of MPL and THPO mutations in Europe; 2) first international quality test of the detection of MPL mutations; 3) on-going study of new THPO and MPL mutations in HT cases; 4) on-going study of the histopathology of MPN without JAK2 mutation. WG 3: 1) list of laboratories responsible for the diagnosis of HE in Europe; 2) consensus on a diagnostic algorithm for the diagnosis of HE; 3) close interaction with COST Action TD0901 (HypoxiaNet) to facilitate the discovery of new genes of interest for the diagnosis of HE; 4) exchange of positive control samples for the main mutations responsible for HE; 5) study of idiopathic erythrocytosis. WG 4: 1) MPN&MPNr-EuroNet website: www.mpneuronet.eu; 2) organization of bi-annual meetings (5th meeting: March 7–9, 2012, Belfast, United Kingdom); 3) organization of annual training schools: a May training school dedicated to the molecular detection of JAK2 and MPL mutations (in Nîmes, France), and an October training school dedicated to hereditary erythrocytosis (in Coimbra, Portugal); 4) financial support for short term scientific missions for exchange and collaborative studies between participating institutions. Conclusion: MPN&MPNr-EuroNet will enable European researchers, biologists and clinicians to define new diagnostic tools and exchange technologies. MPN&MPNr-EuroNet is open to all interested physicians and scientists and we invite new members, including those from outside Europe, to join. Scholarships are available to finance participation in meetings and training schools, and to facilitate exchanges between participating institutions. For detailed information on all MPN&MPNr-EuroNet activities, see www.mpneuronet.eu. Disclosures: Schnittger: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Vannucchi:Novartis: Honoraria.

Analysis of JAK2 V617F Mutation and Its Clinical Significance in Patients with Thrombocythemia and Other Myeloproliferative Neoplasms in Chinese

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4687-4687
Author(s):  
Yue Xu ◽  
Changxin Yin ◽  
Han He ◽  
Lingling Shu ◽  
Fuqun Wu ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Conflicts Of Interest ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Jak2 V617f Mutation ◽  
Jak2 Mutation ◽  
Western Countries ◽  
Arms Pcr ◽  
V617f Mutation

Abstract Abstract 4687 JAK2 mutation is commonly found in Philadelphia-negative myeloproliferative neoplasms (MPNs). In Western countries, this mutation is found in approximately 96 percent of people with polycythemia vera, half of individuals with essential thrombocythemia or primary myelofibrosis. We used the method of amplification refractory mutation PCR (ARMS-PCR) to investigate MPN patients in China. We focused our study on patients with essential thrombocythemia (ET). ARMS-PCR was used to detect JAK2 V617F mutation in the bone barrow (BM) or peripheral blood of 37 MPN patients, which consisting of 7 ET, 5 polycythemia vera (PV), 5 chronic myeloid leukemia (CML), 5 chronic idiopathic myelofibrosis (CIMF), as well as 15 suspected MPNs. 17 cases of JAK2 V617F mutation (45.9%) were found in 37 patients, including 4 ET (57.1%), 4 PV (80.0%), 3 CIMF (60.0%), 6 suspected MPNs (40.0%). We did not find JAK2 V617F in the patients with CML. Our results indicated that the frequency of JAK2 V617F mutation in bcr/abl-negative MPNs in Chinese is similar to that in MPN patients in Western countries. At the same time, ARMS-PCR can distinguish the mutation is heterozygous or homozygous. Most patients were heterozygous for JAK2 but only a few were homozygous. In conclusion, our study showed that JAK2 V617F mutation frequency in Chinese MPN patients is similar to that in patients with this disorder in the West. It is the major molecular genetic abnormality in bcr-abl negative MPN and it can be used for diagnosis of MPN in China. Disclosures: No relevant conflicts of interest to declare.

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