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Summary: Recently, an antibody which inhibits the glycoprotein A repetitions predominant (GARP)‐mediated release of active transforming growth factor beta (TGFβ) from the TGFβ propeptide latency‐associated peptide (LAP) showed preclinical activity in a murine model of the chronic myeloproliferative neoplasms (MPN). Consequently, we investigated the expression of the immunosuppressive molecules LAP and GARP on peripheral blood lymphocytes from 56 MPN patients and 11 healthy donors (HD). We found that lymphocytes from patients with MPN express higher levels of LAP and GARP with no strong differences found between the different MPN diagnoses. The impact of clinical parameters on the expression of LAP and GARP by lymphocytes showed that patients with calreticulin (CALR)mut MPN have increased expression compared with HD and patients with the Januskinase2 (JAK2) mutation. The fraction of lymphocytes bound to activated platelets (aPLT) strongly correlate to LAP and GARP expression suggesting that it is not the lymphocytes themselves but aPLT, which confer the increased expression of GARP and LAP on MPN patient lymphocytes. Notably, no differences in neither platelet counts nor anti‐thrombotic therapy was identified between patients with JAK2‐ and CALRmut patients. Analysis of platelet gene expression failed to identify differences in expression of relevant genes between JAK2‐ and CALRmut patients. [ABSTRACT FROM AUTHOR]

Background: Essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (MF) are myeloproliferative neoplasms (MPN). Inflammation is involved in the initiation, progression, and symptomology of the diseases. The gut microbiota impacts the immune system, infection control, and steady‐state hematopoiesis. Methods: We analyzed the gut microbiota of 227 MPN patients and healthy controls (HCs) using next‐generation sequencing. We expanded our previous results in PV and ET patients with additional PV, pre‐MF, and MF patients which allowed us to compare MPN patients collectively, MPN sub‐diagnoses, and MPN mutations (separately and combined) vs. HCs (N = 42) and compare within MPN sub‐diagnoses and MPN mutation. Results: MPN patients had a higher observed richness (median, 245 [range, 49–659]) compared with HCs (191.5 [range, 111–300; p =.003]) and a lower relative abundance of taxa within the Firmicutes phylum; for example, Faecalibacterium (6% vs. 14%, p <.001). The microbiota of CALR‐positive patients (N = 30) resembled that of HCs more than that of patients with JAK2V617F (N = 177). In JAK2V617F‐positive patients, only minor differences in the gut microbiota were observed between MPN sub‐diagnoses, illustrating the importance of this mutation. Conclusion: The gut microbiota in MPN patients differs from HCs and is driven by JAK2V617F, whereas the gut microbiota in CALR patients resembles HCs more. [ABSTRACT FROM AUTHOR]

Background: The Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are associated with a huge comorbidity burden, including an increased risk of cardiovascular diseases. Recently, chronic inflammation has been suggested to be the driving force for clonal evolution and disease progression in MPN but also potentially having an impact upon the development of accelerated (premature) atherosclerosis. Objectives: Since chronic inflammation, atherosclerosis, and atherothrombosis are prevalent in MPNs and we have previously shown oxidative stress genes to be markedly upregulated in MPNs, we hypothesized that genes linked to development of atherosclerosis might be highly deregulated as well. Methods: Using whole blood gene expression profiling in patients with essential thrombocythemia (ET; n = 19), polycythemia vera (PV; n = 41), or primary myelofibrosis (PMF; n = 9), we herein for the first time report aberrant expression of several atherosclerosis genes. Results: Of 84 atherosclerosis genes, 45, 56, and 46 genes were deregulated in patients with ET, PV, or PMF, respectively. Furthermore, BCL2L1, MMP1, PDGFA, PTGS1, and THBS4 were progressively significantly upregulated and BCL2 progressively significantly downregulated from ET over PV to PMF (all FDR <0.05). Conclusions: We have for the first time shown massive deregulation of atherosclerosis genes in MPNs, likely reflecting the inflammatory state in MPNs in association with in vivo activation of leukocytes, platelets, and endothelial cells being deeply involved in the atherosclerotic process. [ABSTRACT FROM AUTHOR]

Patients with accelerated or blast phase myeloproliferative neoplasms have a dismal prognosis. The report by de Castro et al. provides important information on the rationale and prospect for a novel therapeutic approach combining interferon‐alpha2 with 5‐azacytidine and a JAK1‐2 inhibitor (ruxolitinib) to be explored in well‐designed clinical trials. Commentary on: Castro et al. Ratio of stemness to interferon signalling as a biomarker and therapeutic target of myeloproliferative neoplasm progression to acute myeloid leukaemia. Br J Haematol 2024;204:206–220. [ABSTRACT FROM AUTHOR]

Few studies have assessed healthcare resource utilization (HRU) in patients with Philadelphia‐negative myeloproliferative neoplasms (MPN) using a matched cohort design. Further, no detailed assessment of HRU in the years preceding an MPN diagnosis exists. We conducted a registry‐based nationwide Danish cohort study, including patients with essential thrombocythemia, polycythemia vera, myelofibrosis, and unclassifiable MPN diagnosed between January 2010 and December 2016. HRU data were summarized annually from 2 years before MPN diagnosis until emigration, death, or end of study (December 2017). We included 3342 MPN patients and 32 737 comparisons without an MPN diagnosis, matched on sex, age, region of residence, and level of education. During the study period, the difference in HRU (rate ratio) between patients and matched comparisons ranged from 1.0 to 1.5 for general practitioner contacts, 0.9 to 2.2 for hospitalizations, 0.9 to 3.8 for inpatient days, 1.0 to 4.0 for outpatient visits, 1.3 to 2.1 for emergency department visits, and 1.0 to 4.1 for treatments/examinations. In conclusion, MPN patients had overall higher HRU than the matched comparisons throughout the follow‐up period (maximum 8 years). Further, MPN patients had substantially increased HRU in both the primary and secondary healthcare sector in the 2 years preceding the diagnosis. [ABSTRACT FROM AUTHOR]

A population-based cohort study published in the European Journal of Haematology found that individuals diagnosed with myeloproliferative neoplasms (MPNs) have an increased risk of developing dementia compared to the general population. The risk varied depending on the specific subtype of MPN, with patients with essential thrombocythemia (ET), polycythemia vera (PV), and chronic myelofibrosis (MF) having higher dementia risks. The study suggests that chronic inflammation and reduced cerebral blood flow may contribute to dementia development in MPN patients. However, further research is needed to understand the association and consider factors such as gender, lifestyle, and treatment effects. Screening for MPNs in dementia patients may be beneficial in identifying undiagnosed cases and initiating treatment. [Extracted from the article]

Summary: The effects of smoking on the molecular response (MR) and overall survival (OS) in patients with chronic myeloproliferative neoplasms (MPNs) have not been investigated before. We analysed a historical cohort of 498 consecutive patients diagnosed with MPNs. Moreover, we analysed a subgroup of 270 consecutive patients with MPNs with > 1 measurement of the JAK2V617F variant allele frequency. The data were analysed using Kaplan–Meier plots and Cox regression analysis, along with linear regression models. In all patients, the rate of MR was significantly higher in never‐smokers compared with current smokers in the univariate model (HR, 1·9; 95% CI, 1·1–3·3; P = 0·033) and the multivariate model (HR, 1·9; 95% CI, 1·1–3·5; P = 0·029). Similar findings were observed with different cut‐off values for a partial MR. A subgroup analysis including only interferon‐α2‐treated patients showed similar results. In multivariate analyses, the OS was significantly better for never‐smokers (HR, 0·46; 95% CI, 0·29–0·75; P = 0·002) than current smokers. The differences were more pronounced in the pegylated interferon‐α2‐treated patients. However, no significant interaction of interferon‐α2 treatment was observed. In conclusion, we found that tobacco smoking reduced the rate of MR and OS in patients with MPNs. Cessation of smoking should be encouraged. [ABSTRACT FROM AUTHOR]

Abstract: Interferon‐α2 reduces elevated blood cell counts and splenomegaly in patients with myeloproliferative neoplasms (MPN) and may restore polyclonal hematopoiesis. Its use is limited by inflammation‐mediated toxicity, leading to treatment discontinuation in 10‐30% of patients. Ruxolitinib, a potent anti‐inflammatory agent, has demonstrated benefit in myelofibrosis (MF) and polycythemia vera (PV) patients. Combination therapy (CT) with these two agents may be more efficacious than monotherapy with either, potentially improving tolerability of interferon‐α2 as well. We report the preliminary results from a phase II study of CT with pegylated interferon‐α2 and ruxolitinib in 50 MPN patients (PV, n = 32; low‐/intermediate‐1‐risk MF, n = 18), the majority (n = 47) being resistant and/or intolerant to interferon‐α2 monotherapy. Objectives included remission (2013 revised criteria encompassing histologic, hematologic, and clinical responses), complete hematologic response (CHR), molecular response, and toxicity. Follow‐up was 12 months. Partial remission (PR) and sustained CHR were achieved in 9% and 44% of PV patients, respectively. In MF patients, complete or partial remission was achieved in 39%, and sustained CHR in 58%. The median JAK2V617F allele burden declined significantly in both groups. Hematologic toxicity was the most common adverse event and was managed by dose reduction. Thirty‐seven serious adverse events were recorded in 23 patients; the discontinuation rate was 20%. We conclude that CT with interferon‐α2 and ruxolitinib is efficacious in patients with low‐/intermediate‐1‐risk MF and, to a lesser extent, in patients with PV. These preliminary results encourage phase III studies as well as a study with CT in newly diagnosed MPN patients. [ABSTRACT FROM AUTHOR]

High‐risk mutations are associated with poor response to interferon‐α2. Early treatment with interferon‐α2 is recommended in patients who have early myelofibrosis without high‐risk mutations. See also pages 2680‐7. [ABSTRACT FROM AUTHOR]

Objective In an era of controversy in regard to 'hydroxyurea-leukaemogenicity' and when interferon-alfa2 ( IFN) is being revived in the treatment of Philadelphia-negative myeloproliferative neoplasms ( MPNs), we aim in this single-centre observational study to describe the frequencies of second malignancies in a cohort of MPN patients treated with hydroxyurea ( HU) or IFN monotherapy or the combination of these agents. Patients and methods Records of a MPN cohort of 196 patients were reviewed, and a retrospective analysis was performed on 90 patients treated with HU, 38 patients treated with IFN and 68 patients treated with both IFN and HU. Logistic regression was used to compare frequencies in second malignancies. Results Patients treated with HU had a significantly higher risk of developing all second malignancies compared with patients treated with IFN [ HU vs. IFN: OR of 4.01 (95% CI: 1.12-14.27, P-value: 0.023) and HU- IFN vs. IFN: OR 5.58 (95% CI: 1.55-20.15, P-value: 0.004)]. Conclusion We have found an increased risk of second malignancies in MPN patients treated with HU compared with patients treated with IFN. [ABSTRACT FROM AUTHOR]

The prolongation of cardiac repolarization ( QT interval) has been investigated in studies of patients with secondary iron overload. However, no previous population-based study examining the effect of increased iron stores on QT interval prolongation has previously been undertaken. We tested the hypothesis that increased iron stores and haemochromatosis genotype (genetically increased iron stores) are associated with prolongation of the QT interval. We included 20 261 individuals from the Danish General Suburban Population Study and examined differences in QT interval according to ferritin concentration, transferrin saturation, iron concentration, transferrin concentration and haemochromatosis genotype (C282Y/C282Y). Furthermore, we performed a meta-analysis of case-control studies on thalassaemia major patients and QT interval. Age- and C-reactive protein-adjusted mean corrected QT ( QTc) intervals for ferritin concentration ≥99% vs. ≥25-<50% percentile were 418·9 ms vs. 412·7 ms in men ( P < 0·001) and 422·4 ms vs. 419·1 ms in women ( P = 0·78). Corresponding values for transferrin saturation were 417·6 ms vs. 412·6 ms in men ( P = 0·02) and 421·5 ms vs. 419·4 ms in women ( P = 0·86). The associations were not explained by inflammation and haemochromatosis genotype was not associated with QT interval length. In conclusion, increased iron stores, independent of haemochromatosis genotype and inflammation, are associated with prolongation of the QTc interval in men. This is a novel finding. In addition, the meta-analysis showed prolonged QT interval in thalassaemia major patients compared to healthy controls. [ABSTRACT FROM AUTHOR]

Objective A single-institution case-control study was conducted to test the hypothesis that a history of smoking was associated with a higher risk of developing MPNs compared to CLL. Methods Cases ( n = 323) were all MPN patients diagnosed in a 10-year period, and controls ( n = 333) were all patients with CLL diagnosed during that same period. Odds ratios and 95% confidence intervals were calculated and adjusted for gender and age by logistic regression. Results A significant association between a personal history of smoking and the risk of MPNs compared to CLL were observed for all MPNs ( OR = 1.73, 95% CI 1.25-2.40) and for the WHO 2008 classified MPNs ( OR = 1.64, 95% CI 1.16-2.30). Conclusions No other larger case-control study has described a positive association between the risk of MPN and a history of smoking in the general MPN population. This association might be explained by the chronic inflammatory state and oxidative stress in response to smoking, eliciting genomic instability in the stem cell compartment and ultimately clonal evolution resulting in MPNs. [ABSTRACT FROM AUTHOR]

Key clinical message The inflammation-mediated comorbidities in myelofibrosis ( MF) and related neoplasms (MPNs) likely reflect the concurrent immune deregulation and systemic inflammatory nature of the MPNs, emphasizing the link between chronic systemic inflammation, immune deregulation, and the malignant clone. JAK1-2 inhibitors in MF-patients reduce constitutional symptoms and splenomegaly, but also taget autoimmune and inflammation-mediated comorbidities. [ABSTRACT FROM AUTHOR]

Madelung A, Bzorek M, Bondo H, Zetterberg E, Bjerrum O W, Hasselbalch H C, Scheding S & Ralfkiaer E (2012) Histopathology 60, 554-560 A novel immunohistochemical sequential multi-labelling and erasing technique enables epitope characterization of bone marrow pericytes in primary myelofibrosis Aim: In Philadelphia (Ph)-negative chronic myeloproliferative neoplasms, increased microvascular density, bizarre vessel architecture and increased number of pericytes are among the distinct histopathological features. The aim of this study was to characterize bone marrow pericytes in primary myelofibrosis (PMF) using a novel multi-labelling immunohistochemical technique. Methods and results: Bone marrow biopsies from a normal donor ( n = 1) and patients with PMF ( n = 3) were subjected to an immunohistochemical sequential multi-labelling and erasing technique (SE-technique). Antigens of interest in the first and/or second layer were detected with an immunoperoxidase system and visualized with aminoethylcarbazole. After imaging, erasing and blocking of immunoreagents, the slides were stained with a traditional double immunolabelling procedure. In addition, we applied a Photoshop® colour palette, creating a single composite image of the sequential staining procedures. We successfully applied four layers of antibodies on one slide using CD146, smooth muscle actin, CD34, CD271 and Ki67 in different combinations. The SE-technique significantly improves morphological and phenotypical studies in bone marrow specimens. Conclusions: To our knowledge, the SE-technique is the first to multi-label antigens, identifying vessel and pericyte architecture in bone marrow by light microscopy. This technique may unravel novel aspects of the composition of the microvessel structures in patients with PMF and related neoplasms. [ABSTRACT FROM AUTHOR]

Summary This study assessed the grade of bone marrow (BM) fibrosis and its association with a seromarker for collagen-III formation and fibrosis-related cytokines in 25 immune thrombocytopenia (ITP) patients treated with thrombopoietin receptor agonists (Tpo-RA) who had at least one BM biopsy. Assessment of 8 pre- and on-treatment BM biopsies revealed statistically significant increases in reticulin. Reticulin in biopsies performed after a median of 1·4 years of treatment was graded: MF-0 in 3 (12%), MF-1 in 19 (76%), MF-2 in 2 (8%) and MF-3 in 1 (4%). No cytogenetic or flow-cytometric abnormalities were detected. Median pretreatment Procollagen III N-propeptide (PIIINP) (6·6 μg/l) was significantly higher than on-treatment levels (5·6 μg/l); both were higher than controls (3·4 μg/l; P < 0·001). PIIINP was negatively correlated with treatment duration ( r = −0·49) suggesting a decelerated reticulin production over time. There was a trend towards an association between grade of reticulin and PIIINP. Transforming growth factor (GF)-beta and basic-Fibroblast GF were not different between patients and controls but Hepatocyte GF (HGF), an anti-fibrotic cytokine, was significantly elevated in patients. In conclusion, low-grade BM reticulin fibrosis is seen in most ITP patients on Tpo-RA. The novel findings of decreasing PIIINP and elevated HGF need further investigation to explore their significance in BM fibrogenesis. [ABSTRACT FROM AUTHOR]

The article discusses a study on whether the JAK2V617F status influences the amount of STAT3- and STAT5 phosphorylation in bone marrow biopsies from patients with myelopoliferative neoplasms (MPN), whether a correlation exists between increasing JAK2V617F allel burden and the grade of phosphorylation and if these measurements adds to the differentiation between disease entities. Bone marrow biopsies from patients with MPNs were collected from September 2005 to September 2009. It concludes that the JAK2V617F can be suppressed by more malignant cells.

Gene expression profiling studies have unraveled deregulation of several genes that might be of pathogenetic importance for the development and phenotype of the Philadelphia-negative chronic myeloproliferative neoplasms. In the context of interferon-alpha2 as a promising therapeutic agent, we focused upon the transcriptional profiling of interferon-associated genes in patients with essential thrombocythemia (ET) ( n = 19), polycythemia vera (PV) ( n = 41), and primary myelofibrosis (PMF) ( n = 9). Using whole-blood transcriptional profiling and accordingly obtaining an integrated signature of genes expressed in several immune cells (granulocytes, monocytes, B cells, T cells, platelets), we have identified a number of interferon-associated genes to be significantly deregulated but with a highly significant deregulation of interferon-inducible gene 27 (IFI27) (ET, PV, and PMF, fold change 8, 16, and 30, respectively). The striking deregulation of IFI genes may reflect a hyperstimulated but insufficient immune system being most enhanced in patients with advanced myelofibrosis, in whom the IFI27 gene displayed an exceedingly high expression. The interferon signature may reflect primary myelofibrosis as the burn-out phase of chronic inflammation which ultimately elicits clonal evolution and expansion owing to an exaggerated but incompetent antitumor immune response. Finally, IFI27 may be a novel biomarker of disease activity and tumor burden in patients with CMPNs. [ABSTRACT FROM AUTHOR]

Background and objectives: The JAK2 V617F tyrosine kinase mutation is present in the great majority of patients with polycythemia vera (PV), and approximately half of the patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF). The three distinct disease entities may be considered as three phenotypic presentations of the same JAK2 V617F positive chronic myleoproliferative disorder. Together with physiological and genetic modifiers the phenotype may be determined by the JAK2 V617F allele burden. In the present study, we aimed to asses the JAK2 mutational load and its impact on phenotype. Methods: A highly sensitive real-time quantitative PCR (qPCR) assay was used for quantification of the JAK2 V617F mutational load in 165 patients with Philadelphia chromosome negative chronic myeloproliferative disorders (ET = 40, PV = 95, PMF = 30). Results: We provide evidence of increasing JAK2 V617F allele burden from ET, over PV to PMF ( P = 0.001 and P < 0.00001 respectively). The present data suggests the JAK2 V617F allele burden as a key determinant of the degree of myeloproliferation and myeloid metaplasia reflected by significantly higher levels of white blood cell counts (WBC) ( P = 0.03), CD34 counts ( P = 0.03), lactate dehydrogenase and Polycythemia Rubra Vera gene 1 levels ( P = 0.03 and P < 0.00001 respectively), as well as lower platelet counts ( P = 0.02) and more cases of splenomegaly ( P = 0.001) in homozygous PV patients compared to their heterozygous counterparts. Conclusion: The present study support the concept of the JAK2 V617F positive chronic myeloproliferative disorders as a biological continuum with phenotypic presentation in part influenced by JAK2 V617F mutational load. [ABSTRACT FROM AUTHOR]

A retrospective study of 38 essential thrombocythemia (ET) patients was conducted, reviewing bone marrow biopsies according to WHO criteria using a semiquantitative scoring system. Four patients did not fulfil the WHO criteria for a myeloproliferative disorder and one biopsy was insufficient for evaluation. 14 patients were reclassified as having prefibrotic idiopathic myelofibrosis (IMF), whilst the ET diagnosis was sustained in 19 patients. The individual bone marrow parameters of the reviewed diagnosis showed no correlation with JAK2 V617F mutation status, which was determined by a highly sensitive quantitative real-time PCR (qPCR) method. However, we could confirm previous findings of higher haemoglobin and lower platelet levels in the JAK2 V617F positive patients. Thus, the well-established phenotypic relationship of JAK2-positive ET and PV at the biochemical and molecular level was not recorded as regards bone marrow morphology according to the WHO criteria. Accordingly, the WHO concept of two distinct entities, ET and prefibrotic IMF, does not seem to fit the model of JAK2-positive ET as part of a biological continuum of JAK2 V617F-positive chronic myeloproliferative disorders. [ABSTRACT FROM AUTHOR]

The JAK2 V617F mutation is a frequent genetic event in the three classical Philadelphia-chromosome negative chronic myeloproliferative disorders (Phneg.-CMPD), polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF). Its occurrence varies in frequency in regards to phenotype. The mutation is found in the majority of patients with PV and about half of the patients with ET and IMF. These diseases are clonal stem cell disorders arising in an early stem cell progenitor. The level in the stem cell hierarchy on which the initiating genetic events and the JAK2 V617F mutation occurs is not known. The mutation has so far been detected in all cells of the myeloid lineage, whereas the potential clonal involvement of the lymphoid lineage is controversial. In this study, we detected the JAK2 V617F mutation by real-time quantitative PCR (qPCR) in both B-lymphocytes and T-lymphocytes in a subgroup of patients with Phneg.-CMPDs. These results demonstrate the origin of the JAK2 V617F positive disorders in an early stem cell with both lymphoid and myeloid differentiation potential. [ABSTRACT FROM AUTHOR]

Jensen MK, Holten-Andersen MN, Riisbro R, de Nully Brown P, Larsen MB, Kjeldsen L, Heickendorff L, Brünner N, Hasselbalch HC. Elevated plasma levels of TIMP-1 correlate with plasma suPAR/uPA in patients with chronic myeloproliferative disorders. Eur J Haematol 2003: 71: 377–384. © Blackwell Munksgaard 2003. Chronic myeloproliferative disorders (MPD) are characterized by progressive remodelling of bone marrow stroma as evidenced by increased deposition of extracellular matrix proteins, neoangiogenesis and displacement of normal haematopoietic cells by fibrotic tissue. The family of metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) serve to facilitate and inhibit matrix degradation processes, respectively. In an attempt to investigate potential markers for bone marrow remodelling processes, we investigated plasma levels of total-, free- and complexed TIMP-1, TIMP-2, MMP-2 and MMP-9 in a patient cohort comprising 17 with myelofibrosis (MF), 17 with polycythaemia vera (PV), 15 with essential thrombocythaemia (ET), 1 with a transitional MPD and 30 controls. Compared with controls, total- ( P < 0.0001) (median: 132.6 μg/L vs. 80.8 μg/L), free- ( P < 0.0001) (median: 126.4 μg/L vs. 65.8 μg/L) and complexed TIMP-1 ( P = 0.0009) (median: 17.7 μg/L vs. 10.7 μg/L) concentration was significantly higher in the patients. TIMP-1 was significantly correlated with plasma soluble urokinase plasminogen activator receptor ( P = 0.003) and urokinase plasminogen activator ( P < 0.0001), respectively, suggesting a common cellular origin. No statistical significant difference between TIMP-2 and MMP-2 levels was observed between patients and controls. Furthermore, a significant correlation between free TIMP-1 and TIMP-2 levels was detected ( r = 0.56; P < 0.0001). Median MMP-9 concentration was significantly higher among PV patients compared with controls ( P = 0.0015), and 41% of patients with PV (7/17) had MMP-9 values that were above the mean + 2SD of plasma MMP-9 levels found in controls. The ratio of total TIMP-1/MMP-9 was significantly higher in patients with MF compared with controls ( P = 0.0004). These findings suggest that a disturbed TIMP-1/MMP ratio may reflect an imbalance of the extracellular homeostasis towards an increased matrix deposition promoting fibrosis. [ABSTRACT FROM AUTHOR]

Abstract: Extracellular proteolytic enzymes of the urokinase-type plasminogen activator (uPA) system and the family of metalloproteases play a crucial role in the matrix degradation and tissue remodelling processes characteristic of malignant disorders. The receptor for urokinase plasminogen activator (uPAR) serves to localise and intensify the action of uPA and is expressed on the surface of malignant as well as tumour stromal cells including fibroblasts. A soluble form of uPAR (suPAR) cleaved from its glycosyl-phosphatidylinositol anchor is detected in plasma from healthy individuals and increased levels of suPAR have been found in advanced malignancy, suggesting that suPAR may be a marker of extensive tissue remodelling. In an attempt to clarify whether suPAR might be a marker for bone marrow tissue remodelling we measured plasma suPAR levels in a patient cohort comprising 17 with myelofibrosis (MF), 17 with polycythaemia vera (PV), 15 with essential thrombocythaemia (ET), one with a transitional myeloproliferative disorder evolving from PV and 30 controls. Compared with controls suPAR levels were significantly higher in the patients (P < 0.0001) (median 3.35 vs. 2.32 µg L -1 ). Moreover, in subgroup analyses including patients with MF, PV, and ET, respectively, suPAR levels differed significantly with the highest levels found in patients with MF and PV (MF vs. PV vs. ET; P = 0.0003). When comparing suPAR levels of the individual patient subgroups with controls, only suPAR levels of PV and MF patients were significantly increased ( P < 0.0001). Sixty-five percent of patients with PV and MF (22/34) had suPAR plasma values that were above the mean +2 standard deviations (SD) of controls. The concentration of suPAR was significantly correlated to plasma lactate dehydrogenase, thrombomodulin, and complex of tPA:PAI-1 in the patients. There was no difference between patients and controls when comparing plasma uPA levels. Increased plasma suPAR... [ABSTRACT FROM AUTHOR]

Platelet–leukocyte adhesion may occur as a consequence of platelet activation and possibly plays a key role in the deposition of activated platelets and fibrin in the thrombotic plug. The aim of the present study was to assess by whole blood flow cytometry the presence of circulating platelet–leukocyte aggregates (PLA) and the platelet–leukocyte response to platelet agonist stimulation (ADP and TRAP) in 50 patients with chronic myeloproliferative disorders (MPD) and 30 controls. PLA were identified as platelet–granulocyte/monocyte aggregates (PGMA), platelet–monocyte aggregates (PMA) and defined as the percentage of leukocytes coexpressing the platelet-specific marker glycoprotein Ib. Compared to controls the mean percentage of PGMA and PMA was increased in unstimulated whole blood from patients with MPD (7.98 vs. 1.76%; p<0.001 and 12.34 vs. 3.2%; p<0.001, respectively). The percentage of PGMA was correlated to the platelet count (r=0.46; p<0.001), percentage of P-selectin (r=0.69; p<0.001) and thrombospondin (r=0.58; p<0.001) positive platelets and platelet expression of GPIV (r=0.33; p=0.02). The mean percentage of PGMA and PMA was significantly increased in ADP-stimulated whole blood of patients (57.14 vs. 47.92%; p=0.009 and 54.91 vs. 45.89%; p<0.001, respectively). Compared to patients without a history of thrombosis, patients having experienced microvascular disturbances or a thrombotic event had a higher mean percentage of PGMA and PMA in non-stimulated whole blood (10.07 vs. 6.34%; p=0.025 and 14.81 vs. 10.48%; p=0.021, respectively) and a higher percentage of PGMA in ADP stimulated whole blood (64.32 vs. 51.50%; p<0.01). These data document an increased frequency of PLA in non-stimulated whole blood in MPD associated with a previous history of thrombosis or microvascular disturbances. [ABSTRACT FROM AUTHOR]

In an attempt to characterise the clinical features, incidence and outcome of essential thrombocythaemia (ET) we report our experience in a large unselected series of patients from a well defined region. All new cases of ET in the County of Copenhagen were registered during the period 1977–98. We identified 96 cases of ET, yielding an age‐ and sex‐adjusted annual incidence rate of 0.59/100.000 and a point‐prevalence at last follow up of 11/100.000. The overall incidence rate was 0.31 and 1.00 per 100.000 population during the consecutive periods 1977–89 and 1990–98, respectively, corresponding to a 3.2‐fold increase. Median age at diagnosis was 67 yr (females 68 yr, males 66 yr, range 18–87 yr), and the female to male (F/M) ratio was 2.6:1. At diagnosis, 52% of the patients displayed no ET‐related symptoms and were discovered fortuitously by a routine platelet count. Forty‐eight percent presented with thrombohaemorrhagic phenomena, of which microvascular disturbances of the central nervous system (CNS), extremities and skin were most frequently observed (23%). Compared to patients diagnosed after 1989, patients diagnosed before 1990 had a significantly higher mean platelet count, white blood cell (WBC) count, lactate dehydrogenase (LDH) value and alkaline phosphatase value. With a median follow up of 70 months, 5‐yr survival was 76%, significantly lower than the expected survival of an age‐ and sex‐matched control group (p=0.0052). Thirty‐seven patients experienced a total of 55 thrombohaemorrhagic events during follow‐up, corresponding to an incidence of thrombosis and microvascular disturbances or haemorrhage of 8.1% per pt‐yr and 2.5% per pt‐yr, respectively. The number of patients experiencing thrombosis or microvascular disturbances was significantly higher among the 29 patients who never received acetylsalicylic acid (ASA) compared to the 67 patients who received ASA during follow up (45% vs. 21%; p=0.017). This study provides population‐based data suggesting the benefit of treatment with low‐dose ASA in a non‐selected population of patients with ET. [ABSTRACT FROM AUTHOR]

Chronic myeloproliferative disorders (MPDs) are characterized by a high incidence of thrombohaemorrhagic complications, possibly caused by platelet dysfunction. In an attempt to define platelet functional abnormalities, we assessed the expression of activation-dependent membrane proteins in unstimulated and agonist [ADP and thrombin receptor-activating peptide (TRAP)]-stimulated platelets using quantitative whole blood flow cytometry in samples from 50 MPD patients and 30 controls. The receptor densities of activation markers and glycoproteins (GPs) were quantified using standardized fluorescent beads. Compared with controls, the mean percentage of P-selectin-positive (15·3% vs. 7·2%; P < 0·001) and thrombospondin (TSP)-positive (6·6% vs. 3·7%; P = 0·003) platelets was increased in unstimulated platelets from patients. Patients having experienced a thrombotic event had a higher mean percentage of TSP-positive non-stimulated platelets than patients without a history of thrombosis (9·0% vs. 4·6%; P = 0·02) and a higher GPIV molecules of equivalent fluorochrome (MEF) value (33113 vs. 24471 MEF; P = 0·02). Mean MEF values of monoclonal antibodies (mAbs) against GPIb (34055 vs. 38945 MEF; P < 0·001) and GPIIb/IIIa (1416 vs. 1648 MEF; P < 0·001) were significantly reduced among patients, whereas surface expression of GPIV was increased in patients (28273 vs. 16258 MEF; P < 0·001). In TRAP (10 µmol/l) stimulated whole blood, the MEF of P-selectin (9611 vs. 13293 MEF; P = 0·004) and CD63 (2385 vs. 5177 MEF; P < 0·001) and the ratio of PAC-1/GPIIb/IIIa MEF (0·98 vs. 2·00; P < 0·001) was reduced in patients, indicating either a reduced granule GP content or an intrinsic cellular defect in receptor-mediated granule secretion and activation of the GPIIb/IIIa complex. Expressed as the relative change of MEF compared with unstimulated platelets, TRAP induced decrease of GPIb (7·8% vs. 45%; P < 0·001) and increase of GPIIb/IIIa (49·1% vs. 95·7%; P < 0·001) and GPIV expression (17·8% vs. 55·2%; P < 0·001) was attenuated in patients. [ABSTRACT FROM AUTHOR]

The author reflects the evidence which shows the association of Philadelphia- negative myeloproliferative neoplasms such as polycythemia vera (PV), and myelofibrosis (MF) (MPNs), and thrombocythemia to chronic inflammatory diseases. The author states the hypothesis that chronic inflammation causes premature atherosclerosis. An overview of the increased risk of second cancer in patients with MPNs is offered.

Imatinib mesylate targets the adenosine triphosphate (ATP)-binding sites of the protein tyrosine kinase domains associated with Bcr-abl, the platelet-derived growth factor (PDGF) and c-kit. In idiopathic myelofibrosis (IMF) PDGF is considered to be one of the growth factors responsible for the development of bone marrow fibrosis. Recently, it has been shown that imatinib has antifibrogenic effect on bone marrow fibrosis in chronic myelogenous leukemia. Treatment with imatinib alone in IMF has been associated with significant side effects. In this study, the safety and efficacy of imatinib therapy in IMF, either administered as a single agent or in combination with hydroxyurea (HU) and/or alpha-interferon (IFN-alpha) are evaluated. Eleven patients (median age, 63 years; range, 33-82 years) with IMF (n = 8) or postpolycythemic myelofibrosis (PPMF) (n = 3) were studied All patients had been treated with HU (n = 9) and/or IFN (n = 7) before study entry. In all but one patient, treatment with these agents was discontinued when imatinib therapy was instituted. One patient continued IFN when treatment with imatinib was started. Imatinib was given at a dose of 400 mg/day. Nine patients were in an advanced disease phase. The patients have been followed for a median period of 2 months (range, 0.5-12 months). Treatment with imatinib has been stopped in six patients (55%), because of overt side effects (n = 4), recurrence of transitory dizziness and visual defects owing to a rising platelet count (n = 1), or the occurrence of an acute subdural hemorrhage that was evacuated without neurological deficits (n = 1). In nine patients imatinib treatment was followed by a rise in leukocyte and platelet counts that required combination with HU or IFN. The combined treatment modalities were followed by a rapid decrease in cell counts and were well tolerated apart from IFN side effects. A beneficial effect of imatinib was documented in three patients. It is concluded that leukocytosis and thrombocytosis are seen in most patients with myelofibrosis during treatment with imatinib. Combination therapy with HU or IFN seems safe and well tolerated and followed by a decrease in disease activity. A subgroup of patients in an early disease phase might benefit from imatinib therapy alone., (Copyright 2003 Wiley-Liss, Inc.)

Eighty-three patients with various chronic myeloproliferative disorders [polycythemia vera (PV), essential thrombocytosis (ET), idiopathic myelofibrosis (IMF)] were analyzed for the occurrence of acute myeloid leukemia (AML) and myelodysplasia (MDS) during treatment with hydroxyurea (HU) alone or HU following treatment with busulphan (BU). A total of 58 patients (29 PV, 14 ET, 12 IMF, 3 unclassified) had been treated with HU. Thirty-five of these patients had been treated with HU alone whereas 18 patients had received both HU and BU. The follow-up period was 7.8 years. Twenty-five patients had not been treated with HU. In this patient group, 4 patients had been treated with BU. The follow-up period was 10.5 years. In the HU-treated group (n = 58) 7 patients developed AML and 5 patients MDS. Five of the 12 patients had been treated with HU alone, and 4 patients had received both HU and BU. In the non-HU-treated group (n = 25) 1 patient with PV developed acute myeloid leukemia (AML). This patient had only been treated with phlebotomies. It is concluded that treatment with HU is leukemogenic, with an incidence of AML and MDS of approximately 14% when used alone. The incidence is markedly increased to about 30% when HU is preceded by treatment with BU. HU is not recommended for use in younger patients, in whom non-leukemogenic agents such as alpha-interferon and anagrelide should be used instead., (Copyright 2003 Wiley-Liss, Inc.)