Relationship between JAK2 V617F Mutation Status and Constitutive Mobilization of CD34-Positive Cells into Peripheral Blood in Patients with Chronic Myeloproliferative Disorder.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2586-2586
Author(s):  
Francesco Passamonti ◽  
Elisa Rumi ◽  
Emanuela Boveri ◽  
Daniela Pietra ◽  
Laura Vanelli ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Count ◽  
Peripheral Blood ◽  
Jak2 V617f ◽  
Myeloproliferative Disorder ◽  
Jak2 V617f Mutation ◽  
Jak2 Mutation ◽  
Mutation Status ◽  
Cell Counts ◽  
V617f Mutation

Abstract A gain-of-function mutation of the Janus kinase 2 (JAK2) gene has been recently reported in patients with polycythemia vera (PV), essential thrombocythemia (ET) and chronic idiopathic myelofibrosis (CIMF) [N Engl J Med. 2005 Apr 28;352(17):1779–90]. Abnormal trafficking of CD34-positive cells with increased numbers in the peripheral blood is found in CIMF and in advanced stages of other myeloproliferative disorders. To determine whether the unique JAK2 V617F mutation affects the mobilization of CD34-positive cells into peripheral blood, we studied the relationship between JAK2 mutation status, bone marrow and circulating CD34-positive cells in 72 patients diagnosed according to the WHO criteria. A quantitative real-time polymerase chain reaction (PCR)-based allelic discrimination assay was used for the quantitative detection of the JAK2 V617F alleles in circulating granulocytes. Bone marrow CD34-positive cells were quantitatively assed on paraffin immunostained sections, while circulating CD34-positive cells were enumerated by flow cytometry using a single-platform assay. Overall, 57% of the patients studied carried the JAK2 V617F mutation. Within these patients, median values for JAK2 V617F alleles in circulating granulocytes were as follows: 29% in PV, 4% in ET, 12% in prefibrotic CIMF, 27% in fibrotic CIMF, and 99% in post-PV myelofibrosis. The vast majority of circulating granulocytes were homozygous for the mutation in all but one of patients with post-PV myelofibrosis. Decreased numbers of bone marrow CD34-positive cells and increased counts of circulating CD34-positive cells were detected in patients with fibrotic bone marrow. The higher the degree of fibrosis, the higher the circulating CD34-positive cell count (P<0.001) and the lower the bone marrow CD34-positive cell count (P<0.01). All patients with PV, ET and prefibrotic CIMF, and 7 out of 21 patients with fibrotic CIMF had circulating CD34-positive cell counts lower than 10 x 106/L. Conversely, all patients with post-PV myelofibrosis had counts higher than 10 x 106/L. In univariate analysis, there was an inverse relationship between percentage of JAK2 V617F alleles and bone marrow CD34-positive cells (r=−0.35, P<0.01), and a direct relationship between percentage of JAK2 mutant alleles and circulating CD34-positive cells (r=0.46, P=0.001). Multivariate analysis showed that disease category (P=0.0008) and percentage of JAK2 V617F alleles (P=0.03) were independently related to circulating CD34-positive cell counts. These observations suggest that the JAK2 V617F mutation might be involved in the constitutive mobilization of CD34-positive cells into peripheral blood that is found in patients with myeloproliferative disorder. Nonetheless, constitutive mobilization is present in a considerable portion of patients who do not carry the JAK2 mutation, pointing to additional pathogenetic mechanisms. Findings on patients with PV suggest that transition form heterozygosity to homozygosity for JAK2 V617F may represent an important step in the progression of PV to myelofibrosis. Thus, sequential evaluation of the percentage of JAK2 mutant alleles and enumeration of circulating CD34-positive cells may be useful for disease monitoring in PV.

Relation between JAK2 (V617F) mutation status, granulocyte activation, and constitutive mobilization of CD34+ cells into peripheral blood in myeloproliferative disorders

Blood ◽  
2006 ◽  
Vol 107 (9) ◽  
pp. 3676-3682 ◽  
Author(s):  
Francesco Passamonti ◽  
Elisa Rumi ◽  
Daniela Pietra ◽  
Matteo G. Della Porta ◽  
Emanuela Boveri ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Gene Dosage ◽  
Jak2 V617f ◽  
Myeloproliferative Disorders ◽  
Jak2 V617f Mutation ◽  
Disease Category ◽  
Mutation Status ◽  
Cell Counts ◽  
Cd34 Cells ◽  
V617f Mutation

We studied the relationship between granulocyte JAK2 (V617F) mutation status, circulating CD34+ cells, and granulocyte activation in myeloproliferative disorders. Quantitative allele-specific polymerase chain reaction (PCR) showed significant differences between various disorders with respect to either the proportion of positive patients (53%-100%) or that of mutant alleles, which overall ranged from 1% to 100%. In polycythemia vera, JAK2 (V617F) was detected in 23 of 25 subjects at diagnosis and in 16 of 16 patients whose disease had evolved into myelofibrosis; median percentages of mutant alleles in these subgroups were significantly different (32% versus 95%, P < .001). Circulating CD34+ cell counts were variably elevated and associated with disease category and JAK2 (V617F) mutation status. Most patients had granulocyte activation patterns similar to those induced by administration of granulocyte colony-stimulating factor. A JAK2 (V617F) gene dosage effect on both CD34+ cell counts and granulocyte activation was clearly demonstrated in polycythemia vera, where abnormal patterns were mainly found in patients carrying more than 50% mutant alleles. These observations suggest that JAK2 (V617F) may constitutively activate granulocytes and by this means mobilize CD34+ cells. This exemplifies a novel paradigm in which a somatic gain-of-function mutation is initially responsible for clonal expansion of hematopoietic cells and later for their abnormal trafficking via an activated cell progeny.

JAK2 (V617F) Mutation Status and Neutrophil Apoptotic Resistance in Myelofibrosis with Myeloid Metaplasia (MMM): Correlation and Potential Identification through Phosphorylation Status of STAT3.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3503-3503
Author(s):  
Ruben A. Mesa ◽  
Ayalew Tefferi ◽  
Heather Powell ◽  
Terra Lasho ◽  
David Loegering ◽  
...  
Keyword(s):  
Jak2 V617f ◽  
Jak2 V617f Mutation ◽  
Neutrophil Apoptosis ◽  
Wild Type ◽  
Jak2 Mutation ◽  
Myeloid Metaplasia ◽  
Mutation Status ◽  
Stat3 Phosphorylation ◽  
V617f Mutation ◽  
Myelofibrosis With Myeloid Metaplasia

Abstract Background: We have previously described a resistance to the normal process of apoptosis in neutrophils of patients with myelofibrosis with myeloid metaplasia (MMM) (Blood2003;102:11). Most recently, an activating mutation of JAK2 (V617F) has been described in approximately half of the patients with MMM as well as in variable proportion of patients with other myeloproliferative disorders (MPD). In the current study, we investigated the correlation between JAK2 V617F mutation status and neutrophil apoptosis in MMM. Methods: Neutrophils were isolated by density centrifugation from patients with MMM, other MPDs, and normal controls and assessed for apoptosis at baseline and after 24 hours in culture (IMDM with 20% sterilized fetal calf serum to simulate spontaneous apoptosis). Apoptosis was quantified using three-color flow cytometry using CD45 (to confirm leukocyte presence), annexin V (AN) (marker of apoptosis; detects aberrant externalization of phosphatidylserine during apoptosis), and propidium iodide (PI) (marker of dead cells). Mutation analysis for JAK2 V617F was performed in DNA derived from the isolated neutrophils using genomic DNA amplified by PCR, or extracted from cytogenetic pellets in archived specimens. Apoptotic rates after 24 hours in culture were correlated between patients and controls for both JAK2 mutation status and clinical parameters. Immunoblotting was performed on a subset of patients for correlation of JAK2 mutation status and downstream phosphorylation of the JAK2 target, STAT3, which transcriptionally activates several antiapoptotic genes. Results: Spontaneous neutrophil apoptosis was significantly decreased in MMM patients (n=50; median % apoptotic cells at 41%) compared to both healthy volunteers (n=9; 66%) and patients with other MPD (n=11; 53%) (p=0.002). Resistance to apoptosis in MMM correlated with both anemia (p=0.01) and the presence of the JAK2 V617F mutation (p=0.01). Furthermore, the specific abnormality was more pronounced in patients with homozygous JAK2 V617F; median % apoptotic cells of 47% for patients with wild-type allele (n=22) vs. 39% for heterozygotes (n=23) vs. 22% for homozygotes (n=5; p=0.008). The JAK2 mutation status did not appear dependent on other peripheral blood or clinical features. Neutrophils from 14 MMM patients were assessed simultaneously for both JAK2 mutation and STAT3 phosphorylation status by immunoblotting. Strong expression of phosphorylation of STAT3 was seen in all 3 homozygotes and 4 of 5 heterozygotes, but only 1 of 6 with wild-type allele (p=0.026). Conclusions: Impaired neutrophil apoptosis in patients with MMM correlates with the functional presence of JAK2 V617F in an allele-dose dependent manner and STAT3 phosphorylation. The current observation supports a pathogenetic role for the specific mutation in sustaining clonal myeloproliferation.

Correlation of JAK2 V617F Mutation Status and Cytogenetic Findings in Myeloproliferative Disorders.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3633-3633
Author(s):  
Guoxian Sun ◽  
Frank Buccini ◽  
Elizabeth Fuentes ◽  
James Weisberger
Keyword(s):  
Jak2 V617f ◽  
Myeloproliferative Disorders ◽  
Chromosome Abnormalities ◽  
Jak2 V617f Mutation ◽  
Homozygous Mutation ◽  
Jak2 Mutation ◽  
Mutation Status ◽  
Trisomy 9 ◽  
V617f Mutation ◽  
Trisomy 9P

Abstract Detection of JAK2 V617F mutation is quickly becoming a front-line screening test for suspected myeloproliferative disorders (MPDs), as the mutation shows high frequency and specificity in non-CML MPDs, PV, ET or CIMF. Routine cytogenetics can detect chromosome abnormalities in approximately 20% of MPDs and is very helpful in establishing or confirming the presence of aberrant clonality, although chromosome changes are often numerical gains and losses, deemed non-specific. To see if there is correlation between JAK2 mutation and karyotypes, we studied 57 consecutive patients with clinically and morphologically confirmed diagnosis of non-CML MPDs. JAK2 V617F mutation performed using allele-specific PCR (sensitive to 10% using pyrosequencing) was found in 72% of patients (41/57), whereas clonal chromosome abnormalities were observed in 15.8% (9/57). There was no correlation between JAK2 mutational status and karyotypes. In 41 patients positive for the JAK2 mutation, 6 were cytogenetically abnormal and 35 normal. In 16 patients negative for the mutation, 3 showed abnormal karyotypes and 13 had normal karyotypes (X2 test, p>0.5). Among 6 patients with both JAK2 mutation and an abnormal karyotype, JAK2 mutation was seen in >50% of each sample in 4 patients, consistent with a homozygous mutation. Interestingly, in two cases, one with PV and trisomy 9 and another with MPD unclassifiable and trisomy 9p resulting from an unbalanced translocation between chromosomes 9p and 13, JAK2 mutation was present in >65% of each sample. Trisomy 9 and trisomy 9p are common abnormalities in MPDs, particularly in PV, seen in over 20% of cytogenetically abnormal cases. JAK2 gene is located on 9p24. Mitotic recombination is considered the most likely cause of loss of heterozygosity (LOH) and thus mutant homozygosity which is undetectable at the cytogenetic level. However, in cases with trisomy 9 or 9p, the JAK2 allele genotypes may be G/T/T and/or T/T/T as well as the usual G/T and/or T/T. Our observations suggest that trisomy 9 or 9p should be taken into consideration when interpreting JAK2 mutation status and that further molecular studies are needed to delineate the implication of trisomy 9 or 9p in potential mutant allele selective advantage and clonal evolution in JAK2 mutation positive MPDs.

Coexistence of a Heterozygous JAK2(V617F) Mutation and a Secondary BCR-ABL Translocation within the Compartment of Committed Myeloid Progenitors in Chronic Idiopathic Myelofibrosis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4871-4871
Author(s):  
Martin Bornhaeuser ◽  
Brigitte Mohr ◽  
Uta Oelschlaegel ◽  
Peter Bornhauser ◽  
Swen Jacki ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Philadelphia Chromosome ◽  
Jak2 V617f ◽  
Janus Kinase ◽  
Jak2 V617f Mutation ◽  
Idiopathic Myelofibrosis ◽  
Jak2 Mutation ◽  
V617f Mutation ◽  
Chronic Idiopathic Myelofibrosis ◽  
Philadelphia Chromosome Positive

Abstract Myeloproliferative disorders such as polycythemia vera (PV), essential thrombocytosis (ET) and chronic idiopathic myelofibrosis (CIMF) are clonal hematopoietic diseases with clinical similarities including the risk of transformation into acute myelogeneous leukemia. By definition, these diseases have been separated from Philadelphia chromosome positive (Ph+) CML requiring negativity for the BCR-ABL transcript in PCR studies of bone marrow or peripheral blood. Several groups independently discovered a gain of function mutation of the Janus kinase 2 (JAK2) gene in Ph-negative myeloproliferative diseases. This mutation has been associated with the proliferation of clonogenic progenitors independently of exogenous cytokine stimulation. A sixty-six year old male patient presented with moderate splenomegaly (3 cm under the costal marigin), mild anemia (11.3 g/dl), elevated lactate deyhdrogenase, an increased count of circulating CD34+ cells and a dry bone marrow aspirate. Marrow histology confirmed a prefibrotic stage of chronic idiopathic myelofibrosis (CIMF). Metaphase cytogenetics as well as BCR-ABL FISH were performed on samples from bone marrow, blood and sorted CD34+, CD3+, CD19+ and CD14+ cells from a steady-state back-up leukapheresis. The JAK2(V617F) mutation was confirmed by an allele-specific PCR assay. A screen for BCR-ABL was performed by FISH and PCR in sorted cells as well as in individual colonies (CFU-GM and CFU-E). Four Philadelphia-chromosome positive metaphases could be detected out of 86 derived from the autologous leukapheresis product harvested and cryopreserved as back-up shortly after diagnosis. The BCR-ABL translocation could be detected by fluorescence in-situ hybridisation (FISH) in 2/16 (12.5%) isolated granulocyte/macrophage colonies only whereas all erythroid colonies were negative. The JAK2 mutation was detectable in all clones and was enriched in CD34+ selected cells. The patient experienced progressive splenomegaly despite the achievement of a molecular response measured by quantitative BCR-ABL PCR after treatment with imatinib mesylate. Our in-vitro investigations suggest that the secondary BCR-ABL translocation within the myeloid compartment was of minor pathophysiological relevance in this patient with CIMF harbouring a heterozygous JAK2 mutation.

Study on Clinical and Laboratory Characteristics of Chronic Eosinophilic Leukemia CEL/Hypereosinophilic Syndrome (CEL/HES).

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4637-4637
Author(s):  
Zhijian Xiao ◽  
Yue Zhang ◽  
JianXiang Wang ◽  
Yushu Hao
Keyword(s):  
Bone Marrow ◽  
Hypereosinophilic Syndrome ◽  
Jak2 V617f ◽  
Break Point ◽  
Jak2 V617f Mutation ◽  
Sequencing Analysis ◽  
Mutation Status ◽  
Chronic Eosinophilic Leukemia ◽  
Clonal Proliferation ◽  
V617f Mutation

Abstract Hypereosinophilic syndrome (HES) was a group of diseases associated with persistent eosinophilia without unknown causes, companied with tissue and organ impairments. In 2001, WHO classification of hematopoietic and lymphoid neoplasms classified chronic eosinophilic leukemia (CEL) / HES into the category of chronic myeloproliferative disease, and proposed that the principal basis for the identification of CEL and HES was whether to have the evidence of eosinophils clonal proliferation: CEL had the evidence of eosinophils clonal proliferation, while HES was lack of the evidence of eosinophils clonal proliferation. In this study, 20 cases of CEL/ HES patients were analyzed retrospectively, and nested RT-PCR was used to detect FIP1L1-PDGFRA (F/P) fusion gene; Allele-specific PCR (ASP) conjoint sequencing analysis was used to detect JAK2 V617F, and PCR-RFLP was adopted to detect the mutation status of JAK2 V617F; and PCR is applied to detect TCRγ rearrangement. The clinical and laboratory characteristics of CEL and HES were compared. The ratio of male and female in the 20 cases of patients was 19:1, and the median age was 33 (20–57). F/P detection was positive for 12 cases, and the sequencing confirmed that FIP1L1 break point was at intron 10–12, while PDGFRA break point was at exon 12. There was 1 case of patient found that had JAK2 V617F, and the mutation status analysis showed that it was the mutation on heterozygote. 6 cases were detected having TCRγ gene rearrangement, of which 4 cases were CEL patients, and other 2 cases were HES patients. Most of CEL patients had respiratory symptoms in the early stage, easily companied with circulatory systematic impairment and nervous systematic symptoms. The incidence of splenomegaly of CEL patients was obviously higher than that of HES patients (92.5% vs 42.5%, p=0.031), so did the incidence of anemia and myelofibrosis. There was no difference in EO, WBC, PLT and EO% in peripheral blood as well as bone-marrow eosinophils percentage and bone-marrow primitive cells’ percentage between two groups. Abnormal morphology of eosinophils was often found in CEL patients, with the main manifestation of eosinopenia, basopenia and plasma vacuoles. Our data showed that Eosinophilia is often caught by male, mainly by the young; CEL patients have the main manifestation of the circulatory systematic, respiratory and gastrointestinal symptoms, and have a high incidence of anemia and thrombocytopenia. The routine examination has a little significance for the identification o CEL and HES, while the bone marrow smears morphological examination has a certain help for the diagnosis of CEL; Some HES patients have JAK2 V617F mutation, and further studies on the effect of JAK2 V617F mutation on the pathogenesis of HES can contribute to the diagnosis of such patients in the future and the development of the new targeted drug therapy; Some CEL patients have TCRγ rearrangement, while the relationship of CEL and TCRγ needs a further study.

Tissue Factor and Soluble Markers of Platelet and Endothelial Activation in Essential Thrombocythemia: Relationship with Thrombosis and JAK2 V617F Mutation Status.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2707-2707
Author(s):  
Francisco Cervantes ◽  
Eduardo Arellano-Rodrigo ◽  
Alberto Alvarez-Larran ◽  
Juan-Carlos Reverter ◽  
Neus Villamor ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Essential Thrombocythemia ◽  
Plasma Concentrations ◽  
Jak2 V617f ◽  
Endothelial Activation ◽  
Jak2 V617f Mutation ◽  
Jak2 Mutation ◽  
Mutation Status ◽  
Significant Difference ◽  
V617f Mutation

Abstract There is increasing evidence that platelet and leukocyte activation plays an important role in the thrombotic complications of patients with essential thrombocythemia (ET), but the relationship of both thrombosis occurrence and JAK2 V617F mutation status with the levels of circulating tissue factor (TF) and of soluble markers of platelet and endothelial activation is not known. In 53 ET patients (26 of whom had a previous history of thrombosis), platelet TF expression and plasma levels of TF, soluble P-selectin (sP-selectin), soluble CD40 ligand (sCD40L), von Willebrand factor antigen (VWF:Ag), soluble thrombomodulin (sTM), D-dimer, and prothrombin fragment 1+2 (F1+2), measured by ELISA, were compared with those in matched healthy individuals and correlated with thrombosis occurrence and JAK2 V617F mutation status. ET patients with thrombosis had significantly higher levels of sP-selectin than patients without thrombosis and the controls, whereas ET patients without thrombosis had significantly higher levels than the controls (99.8 ± 47.1 ng/mL versus 70.6 ± 37.8 ng/mL versus 32.4 ± 11.9 ng/mL; p= 0.0001 for all comparisons). The same applied to sCD40L levels (226.7 ± 104.7 pg/mL in patients with thrombosis, 186.4 ± 92.1 pg/mL in patients without thrombosis, and 81.3 ± 22.0 pg/mL in controls; p= 0.0001 for all comparisons). Circulating VWF:Ag and F1+2 levels were higher in ET patients than in controls, but no significant difference was observed between patients with and without thrombosis. No differences in TF platelet expression, TF and sTM plasma concentrations were found between patients and controls. A positive correlation was observed between sP-selectin and F1+2, a marker of thrombin generation (r= 0.378, p= 0.01). Patients with the JAK2 mutation (22 out of 52 assessable patients), as compared with those with the wild-type allele, had significantly higher levels of sP-selectin (p= 0.002), sCD40L (p= 0.03), TF (p= 0.016), VWF:Ag (p= 0.0001), and sTM (p= 0.032). These results support a role for soluble markers of platelet activation in the thrombosis of ET as well as their potential to identify ET patients at greater risk of thrombosis. The association between JAK2 mutation and increased levels of TF and soluble markers of platelet and endothelial activation would suggest that the mutation could promote an enhanced prethrombotic state in ET.

Granulocyte JAK2 (V617F) Mutation Status in Myeloid Neoplasms with Ringed Sideroblasts.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 854-854 ◽  
Author(s):  
Luca Malcovati ◽  
Matteo G. Della Porta ◽  
Daniela Pietra ◽  
Anna Galli ◽  
Erica Travaglino ◽  
...  
Keyword(s):  
Bone Marrow ◽  
X Chromosome ◽  
Jak2 V617f ◽  
X Chromosome Inactivation ◽  
Jak2 V617f Mutation ◽  
Refractory Anemia ◽  
Mutation Status ◽  
Ringed Sideroblasts ◽  
Myeloid Neoplasms ◽  
V617f Mutation

Abstract The most common type of acquired sideroblastic anemia is the myelodysplastic syndrome (MDS) defined as refractory anemia with ringed sideroblasts (RARS). We have previously demonstrated that mitochondrial iron accumulation in this condition is in the form of mitochondrial ferritin (MtF). A gain-of-function mutation of JAK2 is found in most patients with chronic myeloproliferative disorders. A high frequency of this mutation has been also reported in RARS associated with marked thrombocytosis (RARS-T), a provisional entity characterized by marked increase in platelet count, hypercellular marrow with increased megakaryocytes, and ringed sideroblasts. In this study, we investigated the granulocyte JAK2 (V617F) mutation status in 73 patients receiving a diagnosis of myeloid malignancy with ringed sideroblasts at the Division of Hematology, University of Pavia Medical School & IRCCS Policlinico San Matteo Pavia, Italy between 2001 and 2006. According to the WHO classification of the myeloid neoplasms, 23 patients had RARS, 17 had refractory cytopenia with multilineage dysplasia and ringed sideroblasts (RCMD-RS), 16 had refractory anemia with blasts excess, four had MDS with isolated del(5q), and 13 fulfilled the criteria for RARS-T. JAK2 (V617F) mutation status was analyzed on peripheral blood granulocytes through a quantitative real time PCR-based allelic discrimination assay. We compared clinical and biological features of patients with RARS-T with those of patients with refractory anemia or cytopenia with ringed sideroblasts, and found that RARS-T patients had higher neutrophil and platelet counts, lower frequency of cytogenetic abnormalities and higher incidence of the JAK2 (V617F) mutation (P values ranging from &lt;.001 to .02). JAK2 (V617F) was detected in six out of 63 evaluable cases (9.5%), one being diagnosed as MDS with isolated del(5q) and five as RARS-T, resulting in an incidence of mutation in the latter group of 45%. The proportion of mutant alleles ranged between 2.8% and 18.4%, values commonly observed by us in essential thrombocythemia [Blood. 2006 May 1;107(9):3676–82]. Focusing the analysis on RARS-T, a significantly higher hemoglobin level at diagnosis was found in mutated (median value 11.2 g/dL, range 10.1–15.4) compared with non mutated patients (median value 9 g/dL, range 6–9.9) (P=.009). JAK2-positive patients also showed a significantly lower percentage of ringed sideroblasts in the bone marrow (P=.01), and an increased marrow reticulin fibrosis (P=.03). We then evaluated the clonality of hematopoiesis in female patients through analysis of X-chromosome inactivation patterns (XCIPs) in circulating granulocytes and bone marrow CD34-positive cells. Twenty-one out of 23 informative female patients with ringed sideroblasts (91%), as well as 5/6 RARS-T (83%) displayed a clonal pattern of X-chromosome inactivation. These observations suggest that refractory anemia with ringed sideroblasts with marked thrombocytosis is a clonal stem cell disorder significantly associated with the JAK2 (V617F) mutation. This disorder shows both dysplastic and proliferative features, the presence of the mutation being associated with a predominant myeloproliferative phenotype. The recognition of a heterogeneous genetic background in myeloid neoplasms with ringed sideroblasts suggests that different mechanisms might be involved in the induction of mitochondrial ferritin expression in these disorders.

scholarly journals Comparative Analysis of Proinflammatory Cytokine Levels in Peripheral Blood and Bone Marrow of Patients with Myeloproliferative Neoplasms

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4995-4995
Author(s):  
Pu Chen ◽  
Boting Wu ◽  
Xia Shao ◽  
Chanjuan Liu ◽  
Zhenglin Yu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Proinflammatory Cytokines ◽  
Peripheral Blood ◽  
Proinflammatory Cytokine ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Jak2 V617f Mutation ◽  
Cytokine Levels ◽  
V617f Mutation ◽  
Calr Mutations

Abstract Background Myeloproliferative neoplasms (MPNs) are characterized by marker somatic mutations involving JAK2, MPL, and CALR, which lead to constitutive activation of tyrosine kinase signaling cascades, subsequently dysregulated proliferative of myeloid linages, and eventually myelofibrosis or leukemic transformation. Recently, it has been argued that proinflammatory processes are crucial to the pathogenesis and progression of MPNs. A number of proinflammatory cytokines including lipocalin, IL-1, IL-2R, IL-6, IL-8, IL-12, IL-15, and IP-10 have been found elevated in the peripheral blood (PB) of MPN patients. However, there has been limited data on the levels of proinflammatory cytokines in the bone marrow (BM) of MPN patients. The present study determined and compared 40 proinflammatory cytokine levels in the PB and BM plasma of MPN patients with unequivocal molecular background, thus intending to illustrate the proinflammatory features of BM microenvironment as well as to evaluate the credibility of PB cytokine profiles. Methods Newly diagnosed MPN patients (n=12, 8 had JAK2 V617F mutation, 4 had CALR mutations) were included in the present study. PB samples were taken within 48 hours of BM samples. Paired PB and BM plasma cytokine profiles were measured as well as 10 health control PB plasma samples in a single procedure by Quantibody Human Inflammatory Array 3 (RayBiotech, Norcross, GA) which permitted detection of 40 inflammation-associated cytokines. Results Among 12 MPN patients, 8 had JAK2 V617 mutation (6 males, median age 61.5 years), and 4 had CALR mutations (3 males, median age 53.5 years). Positive linear correlations between PB and BM levels were found in 12 proinflammatory cytokines including BLC (r=0.613, p=0.034), I-309 (r=0.872, p<0.001), IL-1α (r=0.666, p=0.018), IL-1β (r=0.929, p<0.001), IL-12p40 (r=0.642, p=0.024), IL-15 (r=0.608, p=0.036), M-CSF (r=0.906, p<0.001), MIG (r=0.596, p=0.041), MIP-1α (r=0.787, p=0.002), MIP-1δ (r=0.648, p=0.023), sTNFRI (r=0.827, p=0.001), and sTNFRII (r=0.644, p=0.024). Compared to health controls, BM levels of G-CSF, IL-2, IL-4, IL-6R, IL-7, IL-8, IL-10, IL-13, MIP-1β, PDGF-BB, RANTES, and TIMP-1 were markedly elevated (all p<0.01), among which IL-2, IL-4, and IL-7 levels were even higher in patients with CALR mutations than those with classic JAK2 V617F mutation (all p<0.05). Conclusions Optimal linear correlation could only be found in limited species of proinflammatory cytokines, especially I-309, IL-1β, M-CSF, and sTNFRI, between PB and BM plasma of MPN patients. Therefore, caution should be recommended during attempts to illustrate the status of inflammation in MPN patients by circulating cytokine markers. A stronger inflammatory component might exist in MPN patients with CALR mutations than those with classic JAK2 V617F mutation. Disclosures No relevant conflicts of interest to declare.

JAK2 V617F Mutation Identifies a Biologically Distinct Subtype of Essential Thrombocythemia Which Resembles Polycythemia Vera.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 253-253 ◽  
Author(s):  
Anthony Green ◽  
Peter Campbell ◽  
Linda Scott ◽  
Georgina Buck ◽  
Keith Wheatley ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Platelet Count ◽  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Response To Therapy ◽  
Jak2 Mutation ◽  
Mutation Status ◽  
Cell Counts ◽  
V617f Mutation

Abstract An acquired V617F mutation in JAK2 occurs in most patients with polycythemia vera (PV) but only half of those with essential thrombocythemia (ET) and idiopathic myelofibrosis. It is not known whether mutation-bearing patients are biologically distinct from those lacking the mutation, or why the same mutation is associated with different phenotypes. Two sensitive PCR-based methods were used to assess the JAK2 mutation status of 806 patients with ET, including 776 from the MRC PT-1 trial and two other prospective studies. The combined cohort provides a unique resource for studying ET, particularly in view of its large size, centralized review of end-points and comprehensive follow-up. The involvement of a large number of secondary and tertiary centers, together with the inclusion of patients in all risk categories, suggest the results are of general relevance. JAK2 mutation status divided the cohort into two distinct subgroups. Mutation-positive patients (53.4%) displayed multiple features resembling PV, with significantly increased hemoglobin levels (p&lt;0.0001), neutrophil counts (p&lt;0.0001), bone marrow erythropoiesis (p=0.001) and granulopoiesis (p=0.005). They suffered more venous thromboses in the year before diagnosis (p=0.04) and during follow-up (p=0.06), together with a higher incidence of polycythemic transformation (p=0.01). To explore the resemblance between V617F-positive ET and PV further, we analysed factors that might constrain erythropoiesis. Compared to mutation-negative patients with ET, mutation-positive patients had lower serum epo (p&lt;0.0001), lower ferritin (p=0.01), and were more likely to be microcytic (p&lt;0.0001). V617F-positive patients were more sensitive to hydroxyurea, requiring lower doses to control platelet count than V617F-negative patients (p&lt;0.0001), a pattern not seen with anagrelide. Despite lower doses of hydroxyurea, V617F-positive patients had greater reductions in hemoglobin, platelet and white cell counts than V617F-negative patients, with no analogous differences noted between V617F-positive and negative patients randomized to anagrelide (p=0.004, p=0.04, p=0.0003 for platelet count, Hb and WCC). Mutation-negative patients did exhibit many clinical and laboratory features characteristic of a myeloproliferative disorder, including cytogenetic abnormalities, hypercellular bone marrow, abnormal megakaryocyte morphology, PRV1 over-expression, growth of epo-independent erythroid colonies, and a risk of myelofibrotic or leukemic transformation. JAK2 mutation status defines two biologically distinct subgroups of ET with differences in presentation, outcome and response to therapy. Our results suggest a model in which V617F-positive ET and PV form a continuum, with the degree of erythrocytosis determined by physiological or genetic modifiers, including iron stores, epo homeostasis, gender and V617F-homozygosity. This concept has major implications for the classification, diagnosis and management of MPDs.

JAK2 V617F Mutation Is Infrequent in “5q-Syndrome” and 5q-Associated MDS.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4833-4833
Author(s):  
Ling Zhang ◽  
Saskia Gueller ◽  
Sophie Raynaud ◽  
Phillip H. Koeffler ◽  
Stephen Lee
Keyword(s):  
Bone Marrow ◽  
Chromosomal Abnormalities ◽  
Bone Marrow Aspiration ◽  
K562 Cells ◽  
Jak2 V617f ◽  
Janus Kinase ◽  
Jak2 V617f Mutation ◽  
Wild Type ◽  
Jak2 Mutation ◽  
V617f Mutation

Abstract Background: V617F mutation in Janus Kinase 2 (JAK2) gene has been found in chronic myeloproliferative disorders (MPD) including polycythemia vera (90%), essential thrombocythemia and chronic idiopathic myelofibrosis (30–50%), and occasionally in myelodysplastic syndromes (MDS). “5q- Syndrome” is a MDS that shares features with MPD and characterized by an atypical megakaryocytic hyperplasia in bone marrow and usually thrombocytosis in peripheral blood. The most common deleted region for this syndrome is 5q13.3q33.1. An interstitial deletion with variable proximal (5q12-14) and distal (5q31-33) breakpoints has been found in other MDS with/without additional chromosomal abnormalities beyond “5q- Syndrome”. To date, JAK2 mutation was detected in 6/97(6.2%) of patients having diagnosis of MDS with “5q- Syndrome”. Design: In our study 21 MDS patients (10 with “5q- Syndrome” and 11 MDS with isolated or complex 5q-) whose diagnosis by both bone marrow aspiration/biopsy and conventional chromosomal analysis were confirmed. Materials and Method: Primers were created to amplify a 460 bp fragment containing the site of JAK2 V617F mutation. Forty-five cycles of PCR were performed at an annealing temperature of 57°C. Resulting PCR product was digested with 2 U BsaXI for 16 hours and with an additional 2 U BsaXI for another 16 hours at 37°C, then analyzed on a 2% agarose gel. The mutant allele remained undigested whereas the wild-type allele was digested into 241 bp, 189 bp and 30 bp fragments. All experiments included a positive (HEL cells) and negative (K562 cells) control. Results: PCR results showed clear wild type PCR patterns in all 21 cases. Conclusion: No JAK2 mutations were detected in 21 patients either with “5q- Syndrome” or other 5q- associated MDS suggesting that JAK2 mutations are infrequent in these MDS patients.

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