Latent Myeloproliferative Disorder Research Articles

Thromboses veineuses à répétition et syndrome myéloprolifératif : positivité secondaire d’une mutation JAK2 cinq ans après l’événement initial

JAK 2 mutation is the molecular event responsible for 95% of polycythemia cases and 50% of thrombocythemia vera and myelofibrosis cases. It can be used as a tool for the diagnosis of myeloproliferative disorders. We report a case illustrating the fact that a negative result does not definitively eliminate the diagnosis. A 40-year old woman, with a medical history of familial deep vein thrombosis, developed thrombosis of the inferior vena cava with extension to the suprahepatic veins and pulmonary embolism. No constitutional or acquired thrombophilia was diagnosed; search for JAK 2 mutation was negative. The patient was treated with fluindione. Five years later, she relapsed with popliteo-femoral and vena cava deep vein thrombosis. The etiological work-up included a PET scan which revealed diffuse uptake in bones and suspected neoplasic bone marrow invasion. Progenitor cell cultures were positive and JAK 2 mutation was confirmed. The bone marrow aspirate had the cytologic appearance of a myeloproliferative disorder. This case illustrates the fact that JAK 2 mutation can be identified several years after onset of a latent myeloproliferative disorder. Cases with a high clinical likelihood should lead to renewed search for this mutation. Secondary discovery of this mutation can be explained by a higher proportion of mutation expressing clones.

Prevalence and clinical outcomes of the 46/1 haplotype, Janus kinase 2 mutations, and ten-eleven translocation 2 mutations in budd-chiari syndrome and their impact on thrombotic complications post Liver Transplantation

Latent myeloproliferative disorders (MPDs) can be identified by Janus kinase 2 (JAK2) mutations in patients with idiopathic Budd-Chiari syndrome (BCS). The incidence and clinical outcomes of JAK2 mutations, novel ten-eleven translocation 2 (TET2) mutations, and the 46/1 haplotype in BCS are unknown for liver transplantation (LT). We undertook molecular studies of 66 patients presenting with BCS and correlated the results with the clinical outcomes. An overt MPD was present in 20% of the cases, and a latent MPD confirmed by the presence of a JAK2 mutation was detected in 45%. Testing for a TET2 mutation identified MPDs at the molecular level in another 7% of the subset of patients with BCS who were evaluated. The 46/1 haplotype frequency was significantly greater in BCS patients versus the general population (P < 0.001). The presence of JAK2 and TET2 mutations had no impact on 1-year survival. Thirty-six patients underwent LT, and 12 developed liver-related thrombotic complications (33%). Ten of these 12 patients required retransplantation. Retransplantation was more likely in those patients who developed liver-related thrombotic complications (P < 0.001). A JAK2 mutation was highly associated with the development of thrombotic complications after LT (P = 0.005). In conclusion, the presence of JAK2V617F predicts hepatic and extrahepatic thrombotic complications after LT. Testing for TET2 mutations can identify another 7% of idiopathic BCS patients with molecular MPDs.

Association of Budd-Chiari syndrome and celiac disease

An association between Budd-Chiari syndrome (BCS) and celiac disease (CD) is uncommon. The aims of our study were to investigate the etiology of BCS and to search for a particular HLA Ag pattern among patients. BCS diagnosis was based on Doppler ultrasound and CD diagnosis on duodenal biopsy, transglutaminase (TGAb) and gliadin antibodies (GAb). Patients were screened for prothrombotic disorders and seven had a PCR-SSO test for HLA genotypes. Patients were treated with anticoagulants and gluten-free diet. Nine patients were included; mean age 27 years (20-42); sex ratio (F/M) 2; mean follow-up duration 31 months (6-54). All patients had endoscopic and histological features of CD. GAb/TGAb were found in 78 % (n=7). Ag HLA found were HLA DQβ1(*)02 (n=6) and DQβ1(*)03 (n=3). Prothrombotic conditions identified were latent myeloproliferative disorder (n=1), protein C deficiency (n=1), probable factor V Leiden (n=1) and oral contraceptive use (n=1). No prothrombotic state could be identified in the five other patients. The BCS-CD association is relatively frequent in our country. Underlying prothrombotic conditions were absent in more than 50 % of cases, suggesting CD plays a role in the occurrence of thrombosis. HLA alleles found are strongly associated with CD, without any particular pattern for the BCS-CD association.

The prevalence of the activating JAK2 tyrosine kinase mutation in chronic porto‐splenomesenteric venous thrombosis

Occult myeloproliferative disorders (MPD) are present in 25% of patients with chronic portal, splenic and mesenteric venous thrombosis (PSMVT). A somatic mutation of JAK2 (JAK2V617F) can be used to identify patients with latent MPD. We evaluated the prevalence and clinical significance of JAK2V617F in patients with chronic PSMVT. Allele-specific polymerase chain reaction was performed to screen for JAK2V617F. Thirty-five patients were tested for JAK2V617F. The underlying pro-coagulant condition was MPD in seven of 35 (20.0%) patients; other aetiologies included hereditary thrombophilia (n = 5), chronic pancreatitis (n = 2), liver abscess (n = 1) and umbilical vein sepsis (n = 3). The remainder were labelled idiopathic, i.e. 17/35 (48.6%) patients. JAK2V617F was detected in 16/35 (45.7%) patients: seven of seven (100%) with MPD, two of 11 (18.1%) with non-MPD acquired conditions and seven of 17 (41.2%) with 'idiopathic' chronic PSMVT. Mean haemoglobin concentration (P = 0.04), haematocrit (P = 0.04), white cell count (P = 0.002) and platelet count (P = 0.05) were significantly higher in patients with JAK2V617F. None of the seven patients with latent MPD have progressed to overt MPD over median follow-up of 85 months. JAK2V617F occurs in 41% of patients with idiopathic chronic portal, splenic and mesenteric venous thrombosis, confirming the presence of latent myeloproliferative disorders, and should form part of the routine pro-coagulant screen.

Acute portal vein thrombosis unrelated to cirrhosis or malignancy. case report of a 29 year old female presenting with abdominal pain

Background: Portal vein thrombosis (PVT) is a rare disorder, perhaps under-diagnosed, too. It results from a combination of systemic and local prothrombotic risk factors. It is associated with a variety of underlying conditions of which liver cirrhosis, malignancy and myeloproliferative disorders (MPDs) are the most common. PVT causes chronic portal hypertension if recanalization is not obtained. Case report: The case is described of a 29 year old women, who developed 2 weeks before admission postprandial right upper and lower quadrant abdominal pain, nausea and vomiting. She was a cigarette smoker and had taken a combined oral contraceptive steroid continuously for 12 years. There were no other risk factors for PVT and she had no history of any disease. On physical examination there was only diffuse abdominal tenderness. CRP was elevated (60.8mg/l) but otherwise laboratory findings were negative. Her blood component levels were within normal ranges, too. Abdominal ultrasound was negative, gastroscopy showed mild gastritis and there was no abnormality on colonoscopy including terminal ileum. Vaginal ultrasound revealed some fluid in Douglas space, but further examination of it gave negative results. Colour Doppler studies and angio-CT confirmed partial PVT. JAK2 mutation proved to be positive, but no MPDs could be confirmed. Anticoagulant therapy was started. Conclusions: Gastroenterologists should not forget that PVT may be the cause of abdominal pain also in non-cirrhotic patients. Colour Doppler abdominal ultrasound is the imaging modality of choice in diagnosing PVT. Identification of underlying prothrombotic states is necessary in these patients. Clinically latent MPDs are important causes of unexplained (previously named idiopathic) PVT. Peripheral blood count might be normal at the time of thrombosis. Testing for JAK2 mutation in all patients with unexplained PVT and prolonged follow-up of these patients is recommended to identify latent MPDs. Gastroenterological as well as haematological follow-ups are indicated.

Prevalence of 46/1 JAK2 Haplotype in Patients with Budd-Chiari Syndrome with and without JAK2V617F and TET2 Mutations.

Abstract 434▪▪This icon denotes an abstract that is clinically relevant.Budd-Chiari Syndrome (BCS) is a group of disorders resulting from obstruction to hepatic venous outflow; myeloproliferative disorder (MPD) accounts for 10-40% of cases. We previously described latent MPD in 58.5% of patients with idiopathic BCS, detected with allele-specific PCR for the JAK2V617F mutation and proposed its use as a screening tool for occult MPD. A predisposing germline JAK2 haplotype (designated 46/1) has since been described as a strong genetic risk factor for MPD and may further characterise latent MPD in BCS. We studied 28 patients with BCS (23 from our original cohort; female n=16, mean age 30.3 years, SD 10) presenting between 1985 and 2008; 14 with the JAK2V617F mutation. Genomic DNA was obtained from archived bone marrow films, fractionated and unfractionated peripheral blood or bone marrow leucocytes. Skin biopsy or CD3+ cells were used as a source of constitutional DNA. DNA was analysed by pyrosequencing for 2 SNPs (rs12340895, rs12343867) which tag the 46/1 JAK2 haplotype. The 46/1 haplotype was detected in 16/28 (57.1%) subjects; 50% of those with the JAK2V617F mutation and 64.3% of those without it. The prevalence in those lacking the JAK2V617F mutation is significantly higher than the frequency in the Wellcome Trust Case Control Consortium cohort of 24% (P=0.0023). 3/28 subjects had previously diagnosed JAK2V617F positive Polycythemia Vera (PV) and all had the 46/1 haplotype, resulting in a prevalence of 36.4% in those with JAK2V617F positive latent MPD. Age at presentation of BCS was significantly lower in those with the 46/1 haplotype (26.4 years compared to 34.8 years, P=0.03). This difference remained significant in those lacking the JAK2V617F mutation (24.0 years compared to 37.6 years, P=0.024) but was not seen in those with the JAK2V617F mutation (P=0.547). There was no difference in presenting clinical features, haematological parameters or treatment between those with and without the 46/1 haplotype. Overall survival in 26/28 patients was 76.9% (median 90 months, range 2 days to 266 months). 17/28 subjects underwent OLT of which 14/17 (11/12 with 46/1 haplotype) are alive at a median of 90 months post transplant (range 9-266 months). 3/17 patients developed post-OLT veno-occlusive disease, all with the JAK2V617F mutation and 2/3 with the 46/1 haplotype. Overt MPD has not developed in any patient without the JAK2V617F mutation; repeat JAK2 mutational analysis was undertaken in 3/14 (2/3 with 46/1 haplotype) and none have acquired the mutation at a mean of 54 months. 19/28 cases were genotyped using SNP markers (Affymetrix SNP6); 3/19 have acquired uniparental disomy (aUPD) on 9p overlapping the JAK2 gene. As TET2 has been postulated as a ‘pre-JAK2' aberration, we sequenced the complete TET2 gene using massively parallel high throughput sequencing (Roche 454); 2/15 patients samples were positive for TET2 mutations. One of our cases had a familial history of PV; the patient, his father and uncle all have JAK2V617F positive PV and were heterozygous for the 46/1 haplotype in DNA extracted from a skin biopsy. 2/3 were homozygous for both the 46/1 haplotype and JAK2V617F mutation in bone marrow granulocytes with SNP6 array data confirming aUPD on 9p. JAK2V617F was detected in cultured in vitro colonies from all 3 family members. All 3 affected family members had normal cytogenetics and normal TET2 gene. 3 unaffected siblings were heterozygous for the 46/1 haplotype both in peripheral blood, CD3+ cells and granulocytes but negative for JAK2V617F mutation and lacked aUPD on 9p. We have found a highly significant prevalence of the 46/1 haplotype in our cohort of BCS, as well as in family members of a patient with JAK2V617F positive BCS and PV. The 46/1 haplotype was detected in patients with idiopathic BCS with and without the JAK2V617F mutation, suggesting a predisposition to idiopathic BCS independent of JAK2V617F mutation acquisition and latent MPD. The prevalence and lower age of presentation in those with the 46/1 haplotype lacking the JAK2V617F mutation supports an alternate, as yet unknown, mechanism predisposing to BCS. The presence of the 46/1 haplotype in unaffected relatives of our JAK2V617F BCS patient suggests that additional germline variation may predispose to or protect from acquisition of JAK2V617F positive disease. Alternatively the 46/1 haplotype may directly confer a cellular growth advantage via increased responsiveness of JAK2 to cytokine stimulation. Disclosures:No relevant conflicts of interest to declare.

JAK2V617F and Prothrombin G20210A Gene Mutations in a Patient With Budd-Chiari Syndrome and Essential Thrombocythemia

Myeloproliferative disorders and the inherited thrombophilias have been described as the main causes underlying the Budd-Chiari syndrome. Moreover, the presence of the JAK2V617F was associated with a higher frequency of Budd-Chiari syndrome in patients who have overt or even latent myeloproliferative disorder. We herein describe a 28-year-old woman who was diagnosed with Budd-Chiari syndrome and later developed an overt myeloproliferative disorder. The patient was found to carry both the JAK2V617F and the prothrombin G20210A mutation in the heterozygous form. The significance of the chronology of diagnosis is highlighted.

Analysis of JAK2V617F and MPLW515L/K Mutation in 30 Patients with Early Stage Myeloproliferative Disease

The classic Bcr-Abl negative myeloproliferative disorders (MPDs) comprise polycythemia vera (PV), essential thrombocythemia (ET), and idiopathic myelofibrosis (IMF). They are considered clonal stem cell disorders. Recently two acquired somatic mutations JAK2V617F and MPLW515L/K have been identified to play an important role in pathogenisis of MPDs. JAK2V617F was detected in almost all PV and nearly 50% in ET and IMF, and the MPLW515L/K mutation occured in only 1% and 4% in ET and IMF respectively. However it is interesting that there are some patients with slightly increased blood cells did not meet the criteria of PV and ET clinically. These early prefibrotic stages of MPDs are overlooked by both the Polycythemia Vera Study Group (PVSG) and the 2001 WHO criteria for the diagnosis of PV, ET and IMF. In order to investigate the prevalence of JAK2V617F and MPLW515L/K mutation in patients with early MPDs without a secondary cause, genomic DNA from bone marrow or blood mononuclear cells of 30 patients with early MPDs was screened by allele specific polymerase chain reaction (AS-PCR) for JAK2V617F and MPLW515L/K mutations and the history of thrombosis was assessed retrospectively by using patient files. Results showed that 14 out of 30 patients (46.7%) were positive for the JAK2V617F mutation, and none of them had the MPLW515L/K. Of the 14 patients with JAK2V617F mutation, a history of thrombosis was comfirmed in 5 patients(35.7%), while none of 16 patients with WT JAK2 had the thrombosis history. The average age of patients with the JAK2V617F mutation exceeded the patients with wild type JAK2(P<0.05), whereas there is no statistical significance on sexual Athe counts of white cell and the occurance of complications (thrombosis) between the patients with and without the JAK2V617F mutation. All the patients have been followed up since onset and 22 patients have available results. Among them, 12 patients with the burden of JAK2V617F turned out to be MPDs, however only 1 out of 10 patients without this mutation also evolved to MPDs. Our results suggest that JAK2V617F mutation can occur in a certain percentage of these early stage of MPDs patients and has help to diagnose early MPDs. Because these patients might have a high rate of complications, proper treatment of the MPD including aspirin and/or cytoreductive therapy is recommended in latent MPDs patients associated with the JAK2V617F mutation.

The JAK2V617F tyrosine kinase mutation identifies clinically latent myeloproliferative disorders in patients presenting with hepatic or portal vein thrombosis

Clinically latent myeloproliferative disorders (MPDs) are important causes of what would otherwise be considered idiopathic hepatic (HVT) or portal vein thrombosis (PVT). They may be difficult to diagnose initially because the peripheral blood count may be normal at the time of thrombosis. A strong association between an activating mutation of the gene encoding one of the Janus kinase family of tyrosine kinases (JAK2(V617F)) and the Philadelphia chromosome-negative MPDs has been identified. We have studied 19 patients with unexplained HVT or PVT and tested for JAK2(V617F). Fourteen (74%) of the 19 patients were heterozygous for JAK2(V617F) but did not meet diagnostic criteria for a MPD at the time of presentation with thrombosis. Prolonged follow-up established the presence of an overt MPD in 13 of the 14 patients after a median duration of 38 months. We recommend testing for JAK2(V617F) in all patients with unexplained HVT or PVT, to identify latent MPDs and prevent potential complications.

The Role of Thrombophilia in Splanchnic Vein Thrombosis

In the last few years, the mechanistic role of thrombophilia due to hypercoagulability and of clonal disorders of hemopoiesis such as chromosome Philadelphia-negative chronic myeloproliferative disorders has been increasingly recognized in primary splanchnic vein thrombosis. As in deep venous thrombosis of the lower limbs, the frequent finding of several prothrombotic disorders in the same individual has led to the concept of primary splanchnic vein thrombosis as a multifactorial disease. Significant progress has been made in determining the molecular bases of inherited thrombophilia, and particularly in the identification of molecular markers of clonal disease in the so-called occult or latent myeloproliferative disorders. In this review article, the authors discuss the current knowledge on the role of thrombophilia in extrahepatic portal vein obstruction and in the Budd-Chiari syndrome, two of the most clinically relevant splanchnic vein thromboses.

Endogenous Erythroid Colony Formation in Patients with Retinal Vein Occlusion

The pathophysiology and causes of retinal vein occlusion (RVO) remain largely unknown. Latent forms of myeloproliferative disorders, which are diagnosed by the presence of in vitro endogenous erythroid colony (EEC) formation, are a well-known cause of intraabdominal vein thrombosis. The suspected diagnosis of a latent myeloproliferative disorder in a patient with RVO, based on the presence of EEC formation, led us to evaluate the association between latent myeloproliferative disorders and RVO. Observational case series in a national eye center. Forty-four patients, with a mean age of 46 years (range, 21-62) and central (n = 38) or peripheral (n = 6) RVO responsible for visual acuity decreased to 6/12 or less. In vitro bone marrow culture. Endogenous erythroid colony formation in cytokine-free culture medium. Conventional diagnostic criteria for myeloproliferative disorders and the JAK2 V617F mutation (which is strongly associated with myeloproliferative disorders) were assessed in RVO patients showing EECs. Endogenous erythroid colony formation was observed in 12 of 44 (27%) patients with RVO, 13 of 35 (37%) patients with Budd-Chiari syndrome, and 52 of 53 (98%) patients with primary polycythemia (positive control groups) but not in 22 healthy bone marrow donors (negative controls) evaluated at the same time and by the same hematology laboratory. Neither conventional nor genetic diagnostic criteria for myeloproliferative disorders were observed in any patient with both RVO and an EEC at the time of diagnosis or during follow-up. Endogenous erythroid colony formation is frequently observed in patients with RVO independently of any detectable myeloproliferative disorder. This opens a new aspect of research on the pathophysiology of this sight-threatening disease.

JAK2 V617F in Patients with Idiopathic Thromboses in Common Locations.

Background: Polycythemia vera and essential thrombocytosis, two of the myeloproliferative disorders (MPD) often characterized by the recurrent somatic missense mutation JAK2 V617F, are associated with an increased risk of arterial and venous thrombosis. Although recent anecdotal reports have suggested the possibility of latent MPDs by finding JAK2 mutations in patients with abdominal venous thromboses (AVT), the usefulness of routine JAK2 V617F testing has not been assessed in a cohort of general hospital patients with idiopathic thromboses in common locations.Methods: To assess the utility of JAK2 V617F testing in patients undergoing thrombophilia workup, we identified all patients with negative molecular diagnostic tests for the Factor V Leiden (FVL) mutation and the prothrombin gene mutation (G20210A) over the course of one year at the Brigham and Women's Hospital. We then determined, by medical record review, the nature of the thrombotic events for which they were being evaluated, and tested their nucleated white blood cell DNA for the JAK2 V617F mutation using the amplification refractory mutation system (ARMS)-PCR assay (which has a lower limit of detection of 5% mutant alleles).Results: From Februrary 2006 to February 2007, 111 patients had negative tests for both FVL and G20210A. Of these, our chart review revealed that 65 had documented thromboses without a history of malignancy or MPD. None of these were found to have the JAK2 V617F mutation. Laboratory hypercoaguability studies for thrombosis by type (from medical record review) were as follows:Protein C deficiency (%)Protein S deficiency (%)Anti-thrombin III deficiency (%)Antiphospholipid Abs (%)Elevated homocysteine (%)JAK2 V617 mutation (%)None (%)CVA/Stroke (n=10)0200100070DVT/PE (n=45)11202413060AVT (n=6)33330017033Other Arterial Thrombosis (n=4)0250025050In terms of clinical risk factors, 27.6% of patients with documented thromboses had had surgery within the prior month, 26.2% were current smokers, and 31.4% of female patients were either pregnant or taking oral contraceptives. 29.2% of all patients had no clinical or laboratory thrombophilic risk factors.Conclusions: About two-thirds of our general hospital patients with thrombosis and negative tests for FVL and G20210A had another underlying thrombophilic risk factor. Adding JAK2 V617F mutation testing as a routine component of the thrombophilia diagnostic workup is not recommended, as it is unlikely to reveal evidence of a putative latent MPD.

JAK2V617F mutation as a marker of a latent myeloproliferative disorder in a patient with Budd-Chiari syndrome and factor V Leiden mutation

JAK2V617F mutation as a marker of a latent myeloproliferative disorder in a patient with Budd-Chiari syndrome and factor V Leiden mutation -

Prevalence of the Activating JAK2 Tyrosine Kinase Mutation V617F in the Budd–Chiari Syndrome

Budd-Chiari Syndrome (BCS) results from obstruction to hepatic venous outflow, with myeloproliferative disorder (MPD) accounting for up to 40% of cases. A number of BCS cases labelled as "idiopathic" do not fulfill the diagnostic criteria for MPD but have features suggestive of a latent form based on hyperplastic bone marrow and erythroid progenitor cell culture; these cases may subsequently develop overt MPD. A clonal mutation in JAK2 tyrosine kinase (JAK2V617F) occurs in a high proportion of patients with MPD and is of use in the characterization of latent MPD in BCS. We performed allele-specific polymerase chain reaction to screen for JAK2V617F in subjects with BCS (n = 41) and polycythemia vera (PV) (n = 20) and in hematologically normal controls (n = 27). AK2V617F was detected in 24 of 41 (58.5%) subjects with BCS, 19 of 20 PV controls, and 0 of 27 hematologically normal controls. Mean hemoglobin concentration and hematocrit were significantly higher in patients with JAK2V617F. Bone marrow was hyperplastic in 16 of 41 subjects (12/16 JAK2V617F positive). Nine of 33 (27.3%) showed endogenous erythroid colony formation (7/9 JAK2V617F positive). Eleven of 41 subjects developed overt MPD (8/11 essential thrombocythemia, 3/11 PV) after the diagnosis of BCS (median, 49 months; range, 8-87 months), and in 90.9% of these JAK2V617F was detected. JAK2V617F occurs in a high proportion of patients with BCS. Latent MPD was missed in a substantial number of our subjects by using standard techniques. Such cases should be screened for JAK2V617F and carefully observed for the subsequent development of overt MPD.

Prevalence of the Activating JAK2 Tyrosine Kinase Mutation V617F in the Budd-Chiari Syndrome.

Budd-Chiari Syndrome (BCS) is a group of disorders resulting from obstruction to hepatic venous outflow; myeloproliferative disorder (MPD) accounts for 10–40% of cases. A number of BCS cases labelled as ‘idiopathic' do not fulfil the accepted diagnostic criteria for MPD but have features suggestive of a latent form of MPD based on hyperplastic bone marrow and spontaneous erythroid colony progenitor cell culture studies; these cases may subsequently develop overt MPD. A clonal mutation in JAK2 tyrosine kinase (JAK2V617F) occurs in a high proportion of patients with MPD and is of potential use in the characterization of latent MPD in BCS. We studied 44 patients with BCS (female n=27, mean age 36.1 years, SD 13) presenting between 1985 and 2005. Genomic DNA obtained from archived bone marrow films was screened by allele-specific PCR for the JAK2V617F tyrosine kinase mutation. JAK2V617F was detected in 27/44 (61.4%) subjects. Fulminant hepatic failure was the presenting feature in 86.4%. 3/38 subjects had previously diagnosed Polycythemia Vera and all of these were JAK2V617F positive. Analysis for hereditary thrombophilia in 32/44 cases showed Factor V Leiden (FVL) heterozygosity (n=2) and Protein C deficiency (n=1); JAK2V617F was detected in one of the FVL cases. Screening for antiphospholipid antibodies and paroxysmal nocturnal hemoglobinuria in 31 and 30 out of 44 cases respectively proved negative. 22/44 cases had splenomegaly of which 72.2% had JAK2V617F detected. Mean hemoglobin concentration was higher in patients with JAK2V617F (12.4 g/dL, SD 2.8) compared to the wild-type allele (10.2 g/dL, SD 2.1)(p=0.005). Mean neutrophil count was similar (p=0.26) in both groups (JAK2V617F 7.8 x109/L, SD 5.5; wild-type 6.1 x109/L, SD 4.5). Mean platelet count was higher (p=0.01) in subjects with JAK2V617F (289 x109/L, SD 192) compared to wild-type (180 x109/L, SD 158). The bone marrow (BM) was hyperplastic in all lineages in 19/44 subjects of which 15 (78.9%) contained the JAK2V617F mutation. Importantly, in 25/44 subjects without hyperplastic BM, 48% had JAK2V617F detected. Clonal cytogenetic abnormalities occurred in 6/44 subjects all of which carried JAK2V617F. In 35 evaluable subjects, 10/35 (28.6%) showed endogenous erythroid colony (EEC) formation (8/10 JAK2V617F positive), and the remainder (25/35) showed no EEC formation (14/25 JAK2V617F positive). Treatment of BCS included anticoagulation (n=44), porto-systemic shunt insertion (n=26) and orthotopic liver transplantation (OLT) (n=15). Overall survival was 81.8% (median 32.5 months, range 2 days-240 months). In the 8 non-survivors, JAK2V617F was detected in 50%. 15/44 subjects underwent OLT (11/15 JAK2V617F positive) of which 14/15 are alive at a median of 36 months post transplant (1–240 months). 14/44 subjects were treated with cytoreductive treatment following diagnosis of BCS and in 92.9% of these JAK2V617F was detected. 5/15 subjects went on to receive cytoreductive treatment following OLT of which all were JAK2V617F positive. We have found a high prevalence of JAK2V617F in patients with BCS. Latent MPD was missed in 12/25 subjects on BM morphology and 14/25 subjects on BM progenitor culture. We suggest that JAK2V617F analysis should be performed in all new cases of BCS. Given their age, these patients are possible candidates for JAK2 targeted therapy.

Clonal hemopoiesis and risk of thrombosis in young female patients with essential thrombocythemia.

Several studies demonstrated a high prevalence of nonrandom X-chromosome inactivation pattern (X-CIP) in essential thrombocythemia (ET). This study explored the incidence of clonal hemopoiesis in myeloid precursors and endogenous erythroid colonies (EECs) in ET patients and its correlation with thrombotic manifestations. Clonal analysis of hemopoiesis using X-CIP was performed in 40 female patients with ET. Median age was 40.5 years (range 20-64), and median platelet count at testing time was 700 x 10(9)/L (range 220-1300 x 10(9)/L). Patients older than 65 years were excluded to reduce age-related skewing. Clonality was assessed on neutrophils, platelets, EECs, and bone marrow CD34(+) cells. Eight (20%) of 40 patients developed thrombosis mainly at diagnosis. Clonal hemopoiesis was found in 17 (42.5%) patients, 15 (37.5%) had polyclonal hemopoiesis, and 8 (20%) were considered uninterpretable due to constitutive skewing. Clonality was confirmed on purified CD34(+) subpopulations from bone marrow, documenting that clonality does not appear lineage-restricted. There were no statistical differences in age at diagnosis, median platelet count at testing time, and length of follow-up. Thrombotic episodes were significantly more frequent in the monoclonal group (p = 0.04, Fisher exact test). Young female patients with ET exhibiting a clonal pattern of hemopoiesis by X-CIP analysis are at higher risk for thrombosis. X-CIP analysis may contribute to defining the individual risk leading to appropriate treatment. X-CIP will allow a correct diagnosis in patients with latent myeloproliferative disorders and thrombosis in unusual sites. Clonal hemopoiesis is easily recognized by X-CIP, but its applicability is limited to the female sex and is hampered by the presence of age-related or constitutive skewing.

Association maladie cœliaque et thrombose veineuse

An association between Budd-Chiari syndrome (BCS) and celiac disease (CD) is uncommon. The aims of our study were to investigate the etiology of BCS and to search for a particular HLA Ag pattern among patients.BCS diagnosis was based on Doppler ultrasound and CD diagnosis on duodenal biopsy, transglutaminase (TGAb) and gliadin antibodies (GAb). Patients were screened for prothrombotic disorders and seven had a PCR-SSO test for HLA genotypes. Patients were treated with anticoagulants and gluten-free diet.Nine patients were included; mean age 27 years (20–42); sex ratio (F/M) 2; mean follow-up duration 31 months (6–54). All patients had endoscopic and histological features of CD. GAb/TGAb were found in 78 % (n = 7). Ag HLA found were HLA DQβ1*02 (n = 6) and DQβ1*03 (n = 3). Prothrombotic conditions identified were latent myeloproliferative disorder (n = 1), protein C deficiency (n = 1), probable factor V Leiden (n = 1) and oral contraceptive use (n = 1). No prothrombotic state could be identified in the five other patients.The BCS–CD association is relatively frequent in our country. Underlying prothrombotic conditions were absent in more than 50 % of cases, suggesting CD plays a role in the occurrence of thrombosis. HLA alleles found are strongly associated with CD, without any particular pattern for the BCS–CD association.

Spontaneous erythroid colony formation as the clue to an underlying myeloproliferative disorder in patients with Budd-Chiari syndrome or portal vein thrombosis.

Budd-Chiari syndrome is a severe disease characterized by occlusion of large hepatic veins leading to death if untreated. Using the classical criteria for the diagnosis of polycythemia vera (PV), essential thrombocythemia (ET), and idiopathic myelofibrosis (IMF), overt PV was the underlying cause in about 10% of the cases and ET or IMF in only a very few. Using spontaneous endogenous erythroid colony (EEC) formation in vitro and/or bone marrow biopsies, a primary myeloproliferative disorder (PMD) was present in 78% of the patients with apparently idiopathic Budd-Chiari syndrome and in about half of the patients with portal, splenic, and/or mesenteric vein thrombosis. The diagnoses in 40 reported cases with hepatic vein thrombosis and spontaneous EEC were overt PV in 25 and latent unclassified PMD in 15 patients. The diagnoses of 40 reported cases with splanchnic vein thrombosis and spontaneous EEC were overt PV in 12, ET in 2, IMF in 2, and latent unclassified PMD with the presence of EEC in 24 patients. Thrombocytosis as a manifestation of myeloproliferative disease was recorded in 34 of 80 (42.5%) patients with spontaneous EEC and Budd-Chiari syndrome or portal vein thrombosis. Thrombocythemia was present in 15 of 41 patients with a proven and in 19 of 39 patients with a latent myeloproliferative disorder. Patients with hepatic vein or splanchnic vein thrombosis associated with a PMD are predominantly females younger than 45. It is concluded that both spontaneous EEC and histopathology from bone marrow biopsy provide specific information as sensitive clues to the diagnosis of all variants of overt and latent myeloproliferative disorders. The association of hepatic and splanchnic vein thrombosis and PMD is not fully understood. Therapeutic options of Budd-Chiari syndrome include anticoagulation with heparin, fibrinolysis followed by oral anticoagulation, and appropriate treatment of the underlying PMD. In case of failure, invasive options include local procedures such as angioplasty or stenting, venous decompression by portal-systemic shunts, or liver transplantation.

Identification of latent myeloproliferative disease in patients with Budd-Chiari syndrome using X-chromosome inactivation patterns and in vitro erythroid colony formation.

Some patients with an early or latent myeloproliferative disorder (MPD) present with Budd-Chiari syndrome (BCS, hepatic vein thrombosis). Cell culture analysis of erythroid progenitors (BFU-E) can be used to discriminate primary from secondary MPD and examination of X-chromosome inactivation (in females) can be used to demonstrate clonality in neoplastic tissues. The present study used these techniques to examine whether a group of 7 female patients who presented with BCS had evidence to support a diagnosis of MPD. Unilateral X-inactivation and therefore clonality can be studied in females heterozygous for X-linked restriction fragment length polymorphisms (RFLP) by differences in methylation between active and inactive chromosomes. Probes for two polymorphic loci, phosphoglycerate kinase (PGK, at Xq13.3 [BstX1 RFLP]) and M27 beta (an anonymous locus DXS255 at Xp11.22 [Pst1 RFLP]) were used to study methylation patterns. All 7 patients were heterozygous using M27 beta and 2/7 were also heterozygous using the PGK probe. Polyclonal patterns of X-inactivation in granulocytes were demonstrated in 3/7, a skewed/monoclonal pattern in 1/7 and aberrant patterns in 3/7 using M27 beta. Two patients who had aberrant patterns of X inactivation with M27 beta demonstrated a skewed/monoclonal pattern with PGK. The results of BFU-E growth patterns and clonality were entirely concordant in 5/6 patients. Thus X-chromosome inactivation patterns, in conjunction with erythroid colony studies, can be used to assist in the diagnosis of an underlying MPD in BCS.

Polycythemia Vera: The Natural History of 1213 Patients Followed for 20 Years

To reassess the natural history of polycythemia vera and to obtain reliable estimates of both incidence of thrombosis and survival for use in defining the sample size for therapeutic clinical trials.Retrospective cohort study of patients with polycythemia who had been followed for 20 years.11 Italian hematology institutions.1213 patients with polycythemia vera, which was diagnosed according to criteria established by the Polycythemia Vera Study Group and commonly used in clinical practice.All-cause mortality, venous and arterial thrombosis, and hematologic and nonhematologic neoplastic disease. Myocardial infarction and stroke were classified as major thrombotic events, and venous and peripheral arterial thrombosis were considered minor thrombotic events. The number of patients who died and the number of those who had major thrombotic events (combined end point) were used as a comprehensive measure of the benefit-risk ratio associated with the use of myelosuppressive agents.634 fatal and nonfatal arterial and venous thromboses were recorded in 485 patients (41%); 36% of these episodes occurred during follow-up in 230 patients (19%), and 64% occurred either at presentation or before diagnosis. Thrombotic events occurred more frequently in the 2 years preceding diagnosis, suggesting a causal relation between the latent myeloproliferative disorder and the vascular event. The incidence of thrombosis during follow-up was 3.4%/y; older patients or those with a history of thrombosis had a higher risk for thrombosis. Overall mortality was 2.9/100 patients per year; thrombotic events and hematologic or nonhematologic cancers had similar effects on mortality. Patients receiving chemotherapy died three to four times more frequently than those not receiving chemotherapy. The increased risk for cancer in patients receiving myelosuppressive agents was seen approximately 6 years after diagnosis. In addition, the combined end point, computed as the sum of the hardest available events (death, nonfatal myocardial infarction, or stroke), suggests that myelosuppressive agents have an overall unfavorable effect.Cytoreduction favorably affects the incidence of thrombotic events, but aggressive treatment seems to be associated with increased risk for neoplasm. These results provide a basis for reevaluating the therapeutic strategy in patients with polycythemia vera and for estimating the size of clinical trials aimed at testing new therapeutic approaches.