Tumor necrosis factor α promotes clonal dominance of KIT D816V+ cells in mastocytosis: role of survivin and impact on prognosis

ABSTRACT

Systemic mastocytosis (SM) is defined by the expansion and accumulation of neoplastic mast cells (MCs) in the bone marrow (BM) and extracutaneous organs. Most patients harbor a somatic KIT D816V mutation, which leads to growth factor-independent KIT activation and accumulation of MC. Tumor necrosis factor α (TNF) is a proapoptotic and inflammatory cytokine that has been implicated in the clonal selection of neoplastic cells. We found that KIT D816V increases the expression and secretion of TNF. TNF expression in neoplastic MCs is reduced by KIT-targeting drugs. Similarly, knockdown of KIT or targeting the downstream signaling cascade of MAPK and NF-κB signaling reduced TNF expression levels. TNF reduces colony formation in human BM cells, whereas KIT D816V+ cells are less susceptible to the cytokine, potentially contributing to clonal selection. In line, knockout of TNF in neoplastic MC prolonged survival and reduced myelosuppression in a murine xenotransplantation model. Mechanistic studies revealed that the relative resistance of KIT D816V+ cells to TNF is mediated by the apoptosis-regulator BIRC5 (survivin). Expression of BIRC5 in neoplastic MC was confirmed by immunohistochemistry of samples from patients with SM. TNF serum levels are significantly elevated in patients with SM and high TNF levels were identified as a biomarker associated with inferior survival. We here characterized TNF as a KIT D816V-dependent cytokine that promotes clonal dominance. We propose TNF and apoptosis-associated proteins as potential therapeutic targets in SM.

N-terminal pro-brain natriuretic peptide is a prognostic marker for response to intensive chemotherapy, early death, and overall survival in acute myeloid leukemia

Patient-related factors are of prognostic importance in acute myeloid leukemia (AML). Likewise, cardiac disorders may limit the tolerance of intensive therapy. Little is known about the prognostic value of N-terminal pro-brain natriuretic peptide (NT-proBNP). We analyzed NT-proBNP levels at diagnosis in 312 AML patients (median age: 61 years; range 17-89 years) treated with 3 + 7-based induction-chemotherapy and consolidation with up to four cycles of intermediate or high-dose ARA-C. NT-proBNP levels were elevated in 199 patients (63.8%), normal (0-125 pg/ml) in 113 (36.2%), and highly elevated (>2000 pg/ml) in 20 patients (6.4%). Median NT-proBNP levels differed significantly among patients with complete remission (153.3 pg/ml), no remission (225.9 pg/ml), or early death (735.5 pg/ml) (p = .002). In multivariate analysis, NT-proBNP, age, and the 2009 European LeukemiaNet (ELN-2009) classification were independent predictors of outcome after induction chemotherapy. Overall survival (OS) differed significantly between patients with normal, moderately elevated, and highly elevated NT-proBNP (p < .001). These differences were observed in all patients and in patients <60 years but not in those ≥60 years. In multivariate analysis, NT-proBNP, age, and ELN-2009 remained independent prognostic variables for OS (p < .01). Together, NT-proBNP is an independent prognostic factor indicating the risk of induction failure, early death, and reduced OS in patients with AML.

Functional Precision Medicine Provides Clinical Benefit in Advanced Aggressive Hematologic Cancers and Identifies Exceptional Responders

Personalized medicine aims to match the right drug with the right patient by using specific features of the individual patient's tumor. However, current strategies of personalized therapy matching provide treatment opportunities for less than 10% of patients with cancer. A promising method may be drug profiling of patient biopsy specimens with single-cell resolution to directly quantify drug effects. We prospectively tested an image-based single-cell functional precision medicine (scFPM) approach to guide treatments in 143 patients with advanced aggressive hematologic cancers. Fifty-six patients (39%) were treated according to scFPM results. At a median follow-up of 23.9 months, 30 patients (54%) demonstrated a clinical benefit of more than 1.3-fold enhanced progression-free survival compared with their previous therapy. Twelve patients (40% of responders) experienced exceptional responses lasting three times longer than expected for their respective disease. We conclude that therapy matching by scFPM is clinically feasible and effective in advanced aggressive hematologic cancers. SIGNIFICANCE: This is the first precision medicine trial using a functional assay to instruct n-of-one therapies in oncology. It illustrates that for patients lacking standard therapies, high-content assay-based scFPM can have a significant value in clinical therapy guidance based on functional dependencies of each patient's cancer.See related commentary by Letai, p. 290.This article is highlighted in the In This Issue feature, p. 275.

Secondary basophilic leukemia in Ph-negative myeloid neoplasms: A distinct subset with poor prognosis

During progression of myeloid neoplasms, the basophil compartment may expand substantially and in some of these patients, a basophilic leukemia is diagnosed. In patients with Ph-chromosome+ chronic myeloid leukemia, acceleration of disease is typically accompanied by marked basophilia. In other myeloid neoplasms, secondary leukemic expansion of basophils is rarely seen. We report on 5 patients who suffered from a myelodysplastic syndrome, myeloproliferative neoplasm, or acute leukemia and developed a massive expansion of basophils during disease progression. In 4 of 5 patients, peripheral blood basophil counts reached 40%, and the diagnosis “secondary basophilic leukemia” was established. As assessed by flow cytometry, neoplastic basophils expressed CD9, CD18, CD25, CD33, CD63, PD-L1, CD123, and CLL-1. In addition, basophils were found to display BB1 (basogranulin), 2D7, tryptase and KIT. In 4 of 5 patients the disease progressed quickly and treatment with azacitidine was started. However, azacitidine did not induce major clinical responses, and all patients died from progressive disease within 3 Y. In in vitro experiments, the patients´ cells and the basophilic leukemia cell line KU812 showed variable responses to targeted drugs, including azacitidine, venetoclax, hydroxyurea, and cytarabine. A combination of venetoclax and azacitidine induced cooperative antineoplastic effects in these cells. Together, secondary basophilic leukemia has a poor prognosis and monotherapy with azacitidine is not sufficient to keep the disease under control for longer time-periods. Whether drug combination, such as venetoclax+azacitidine, can induce better outcomes in these patients remains to be determined in future clinical studies.

Impact of HFE gene variants on iron overload, overall survival and leukemia-free survival in myelodysplastic syndromes

Although iron overload is a clinical challenge, little is known about the clinical impact of HFE-variants in myelodysplastic syndromes (MDS) to date. We analyzed the HFE status in 167 MDS patients and 494 healthy controls. One or more of the 3 HFE-variants (H63D, C282Y, S65C) were found in 65/167 (38.9%) MDS patients and in 164/494 (33.2%) controls. At diagnosis, the median serum ferritin levels were higher in MDS patients with HFE-variants (409 µg/L; range: 23-7415) compared to those without HFE-variants (346.5 µg/L; range: 10-5450) (P=0.62). Moreover, 'HFE-mutated' patients had a slightly faster increase in serum ferritin in follow up examinations. The percentage of patients with HFE-variants was higher in refractory anemia (RA) (22/53=41.5%) or RA with ring sideroblasts (RARS) (17/39=43.6%) compared to RA with excess of blasts (RAEB) (16/46=34.8%) or RAEB in transformation (RAEB-T) (5/17=29.4%). Differences were also detectable when comparing low- and high-risk MDS variants defined by the World Health Organization classification. There was no significant correlation between HFE-variants and MDS-related somatic mutations. Progression-free survival was substantially longer in patients with HFE-variants compared to those without HFE-variants H63D and C282Y (P=0.089). Together, the HFE-variants H63D and C282Y are frequently detected in Austrian MDS patients. These patients have substantially higher ferritin levels at diagnosis, accumulate iron slightly faster and have a better progression-free survival than non-mutated patients.

Prognostic factors and follow-up parameters in patients with paroxysmal nocturnal hemoglobinuria (PNH): experience of the Austrian PNH network

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematologic disease characterized by a deregulated complement system, chronic Coombs-negative, intravascular hemolysis, and a variable clinical course with substantial risk to develop thromboembolic events. We analyzed diagnostic and prognostic parameters as well as clinical endpoints in 59 adult patients suffering from PNH in 5 hematology centers in Austria (observation period: 1978-2015). Median follow-up time was 5.6 years. The median clone size at diagnosis amounted to 55% and was higher in patients with classical PNH (81%) compared to patients with PNH associated with aplastic anemia (AA) or myelodysplastic syndromes (MDS) (50%). The clone size also correlated with lactate dehydrogenase (LDH) levels. In one patient, anemia improved spontaneously and disappeared with complete normalization of LDH after 16 years. Seventeen patients received therapy with eculizumab. The rate of thromboembolic events was higher in the pre-eculizumab era compared with eculizumab-treated patients but did not correlate with the presence of age-related clonal hematopoiesis or any other clinical or laboratory parameters. Peripheral blood colony-forming progenitor cell counts were lower in PNH patients compared with healthy controls. Only two patients with classical PNH developed MDS. Overall, 7/59 patients died after 0.5-32 years. Causes of death were acute pulmonary hypertension, Budd-Chiari syndrome, and septicemia. Overall survival (OS) was mainly influenced by age and was similar to OS measured in an age-matched healthy Austrian control cohort. Together, compared with previous times, the clinical course and OS in PNH are favorable, which may be due to better diagnosis, early recognition, and eculizumab therapy.

Attenuation of canonical NF-κB signaling maintains function and stability of human Treg

Nuclear factor ‘κ‐light‐chain‐enhancer’ of activated B cells (NF‐κB) signaling is a signaling pathway used by most immune cells to promote immunostimulatory functions. Recent studies have indicated that regulatory T cells (Treg) differentially integrate TCR‐derived signals, thereby maintaining their suppressive features. However, the role of NF‐κB signaling in the activation of human peripheral blood (PB) Treg has not been fully elucidated so far. We show that the activity of the master transcription factor forkhead box protein 3 (FOXP3) attenuates p65 phosphorylation and nuclear translocation of the NF‐κB proteins p50, p65, and c‐Rel following activation in human Treg. Using pharmacological and genetic inhibition of canonical NF‐κB signaling in FOXP3‐transgenic T cells and PB Treg from healthy donors as well as Treg from a patient with a primary NFKB1 haploinsufficiency, we validate that Treg activation and suppressive capacity is independent of NF‐κB signaling. Additionally, repression of residual NF‐κB signaling in Treg further enhances interleukin‐10 (IL‐10) production. Blockade of NF‐κB signaling can be exploited for the generation of in vitro induced Treg (iTreg) with enhanced suppressive capacity and functional stability. In this respect, dual blockade of mammalian target of rapamycin (mTOR) and NF‐κB signaling was accompanied by enhanced expression of the transcription factors FOXP1 and FOXP3 and demethylation of the Treg‐specific demethylated region compared to iTreg generated under mTOR blockade alone. Thus, we provide first insights into the role of NF‐κB signaling in human Treg. These findings could lead to strategies for the selective manipulation of Treg and the generation of improved iTreg for cellular therapy.

Correlation of RAS-Pathway Mutations and Spontaneous Myeloid Colony Growth with Progression and Transformation in Chronic Myelomonocytic Leukemia-A Retrospective Analysis in 337 Patients

Although the RAS-pathway has been implicated as an important driver in the pathogenesis of chronic myelomonocytic leukemia (CMML) a comprehensive study including molecular and functional analyses in patients with progression and transformation has not been performed. A close correlation between RASopathy gene mutations and spontaneous in vitro myeloid colony (CFU-GM) growth in CMML has been described. Molecular and/or functional analyses were performed in three cohorts of 337 CMML patients: in patients without (A, n = 236) and with (B, n = 61) progression/transformation during follow-up, and in patients already transformed at the time of sampling (C, n = 40 + 26 who were before in B). The frequencies of RAS-pathway mutations (variant allele frequency ≥ 20%) in cohorts A, B, and C were 30%, 47%, and 71% (p < 0.0001), and of high colony growth (≥20/10⁵ peripheral blood mononuclear cells) 31%, 44%, and 80% (p < 0.0001), respectively. Increases in allele burden of RAS-pathway mutations and in numbers of spontaneously formed CFU-GM before and after transformation could be shown in individual patients. Finally, the presence of mutations in RASopathy genes as well as the presence of high colony growth prior to transformation was significantly associated with an increased risk of acute myeloid leukemia (AML) development. Together, RAS-pathway mutations in CMML correlate with an augmented autonomous expansion of neoplastic precursor cells and indicate an increased risk of AML development which may be relevant for targeted treatment strategies.

The TGF-b/SOX4 axis and ROS-driven autophagy co-mediate CD39 expression in regulatory T-cells

The ectonucleotidase CD39 on human regulatory T-cells (Treg) is an important immune regulator which is dysregulated in autoimmune diseases and cancer immunosuppression. We here define that CD39 expression on Treg is independent of the Treg-specific transcription factors FOXP3 and HELIOS and promoted by canonical TGF-b- and mTOR-signaling. Furthermore, the TGF-b mediated upregulation of CD39 is counteracted by reactive oxygen species (ROS)-driven autophagy. In line, CD39⁺ peripheral blood Treg constitute a distinct lineage with low autophagic flux and absent ROS production. Patients with rare genetic defects in autophagy show supraphysiological levels of CD39⁺ Treg, validating our observations in vivo. These biological processes rely on a distinct transcriptional program with CD39⁺ Treg expressing low levels of two genes with putative involvement in autophagy, NEFL and PLAC8. Furthermore, the TGF-b downstream transcription factor SOX4 is selectively upregulated in CD39⁺ Treg. Overexpression of SOX4 in Treg strongly increases CD39 expression, while Crispr/Cas9-mediated knockout of SOX4 in Treg has the opposing effect. Thus, we identify a crucial role of SOX4 in immune regulation and provide new insights involving the interplay of tolerogenic cues and autophagy in Treg.

Overexpression of PDE4A Acts as Checkpoint Inhibitor Against cAMP-Mediated Immunosuppression in vitro

Malignant cells acquire physiological mechanisms of immunosuppression to escape immune surveillance. Strategies to counteract this suppression could help to improve adoptive immunotherapy regimen. The intracellular second messenger cyclic AMP (cAMP) acts as a potent immunosuppressive signaling molecule in T-cells and is up-regulated by multiple tumor-relevant suppressive factors including prostaglandin E2 (PGE2), adenosine and the functions of regulatory T-cells. Consequently, we aimed to abrogate cAMP signaling in human T-cells by ectopic overexpression of phosphodiesterase 4A (PDE4A). We could show that retroviral transduction of PDE4A into T-cells led to efficient degradation of cAMP in response to induction of adenylate cyclase. Retroviral transduction of PDE4A into CD4⁺ and CD8⁺ T-cells restored proliferation, cytokine secretion as well as cytotoxicity under immunosuppression by PGE2 and A2A-R agonists. PDE4A-transgenic T-cells were also partially protected from suppression by regulatory T-cells. Furthermore, PGE2-mediated upregulation of the inhibitory surface markers CD73 and CD94 on CD8⁺ T-cells was efficiently counteracted by PDE4A. Importantly, no differences in the functionality under non-suppressive conditions between PDE4A- and control-vector transduced T-cells were observed, indicating that PDE4A does not interfere with T-cell activation per se. Similarly, expression of surface markers associated with T-cell exhaustion were not influenced by PDE4A overexpression in long term cultures. Thus, we provide first in vitro evidence that PDE4A can be exploited as immune checkpoint inhibitor against multiple suppressive factors.

The Austrian biodatabase for chronic myelomonocytic leukemia (ABCMML) : A representative and useful real-life data source for further biomedical research

In the Austrian biodatabase for chronic myelomonocytic leukemia (ABCMML) clinicolaboratory real-life data have been captured from 606 CMML patients from 14 different hospitals over the last 30 years. It is the only large biodatabase worldwide in which functional methods such as semisolid in vitro cultures complement modern molecular methods such as next generation sequencing. This provides the possibility to comprehensively study the biology of CMML. The aim of this study was to compare patient characteristics with published CMML cohorts and to validate established prognostic parameters in order to examine if this real-life database can serve as a representative and useful data source for further research. After exclusion of patients in transformation characteristics of 531 patients were compared with published CMML cohorts. Median values for age, leukocytes, hemoglobin, platelets, lactate dehydrogenase (LDH) and circulating blasts were within the ranges of reported CMML series. Established prognostic parameters including leukocytes, hemoglobin, blasts and adverse cytogenetics were able to discriminate patients with different outcome. Myeloproliferative (MP) as compared to myelodysplastic (MD)-CMML patients had higher values for circulating blasts, LDH, RAS-pathway mutations and for spontaneous myelomonocytic colony growth in vitro as well as more often splenomegaly. This study demonstrates that the patient cohort of the ABCMML shares clinicolaboratory characteristics with reported CMML cohorts from other countries and confirms phenotypic and genotypic differences between MP-CMML and MD-CMML. Therefore, results obtained from molecular and biological analyses using material from the national cohort will also be applicable to other CMML series and thus may have a more general significance.

Ascitic fluid polymorphic nuclear cell count impacts on outcome of cirrhotic patients with ascites

Background

Spontaneous bacterial peritonitis (SBP) is defined as an ascitic polymorphonuclear cell count (A-PMN) > 250 cells/µl.

Objective

We aimed to investigate the prognostic value of ascitic fluid cell counts in patients without SBP.

Patients and methods

A total of 178 patients were included and stratified by ascitic cell counts at index paracentesis: A-LEUK-low (<250/µl), A-LEUK-intermediate (250-500/µl) and A-LEUK-SBP (>500/µl) for leukocytes; A-PMN-low (<125/µl), A-PMN-intermediate (125-250/µl) and A-PMN-SBP (>250/µl) for PMN cells.

Results

One-year mortality was comparable between group A-LEUK-SBP (53.9%) and patients with subclinical cell counts (34.5% for A-LEUK-low, 43.5% for A-LEUK-intermediate, log-rank p = 0.547). However, we observed an increase in one-year mortality already in group A-PMN-intermediate with 75% and A-PMN-SBP with 80.9% (vs 40.5% for A-PMN-low, log-rank p = 0.016).Importantly, increases of A-PMN cell counts between two paracenteses were associated with increased mortality: per 100 cells/µl increase of absolute A-PMN cell count: hazard ratio (HR): 1.03 (95% confidence interval (CI): 1.01-1.06), p = 0.005; per 5% increase of relative PMN cell count: HR: 1.15 (95% CI: 1.06-1.26), p = 0.001.

Conclusion

Patients with PMN cell counts of 125-250/µl are at high risk for mortality, which was very similar to SBP patients with PMN cell counts >250/µl. This highlights the need for preventive strategies. The prognostic value of changes in relative ascitic PMN cell counts should be evaluated in future studies.

Association of Platelet-to-Lymphocyte Ratio and Neutrophil-to-Lymphocyte Ratio with the Risk of Thromboembolism and Mortality in Patients with Cancer

Patients with cancer are at risk of developing venous and arterial thromboembolism (VTE and ATE). Elevated platelet-to-lymphocyte (PLR) and neutrophil-to-lymphocyte ratios (NLR) have been suggested as potential biomarkers for cancer-associated chronic inflammation, VTE and mortality. We investigated the association between PLR and NLR with VTE, ATE and mortality in patients with cancer. Within a prospective cohort study, we followed-up patients with newly diagnosed or progressing cancer for objectively confirmed, symptomatic VTE, ATE and death. Fine and Gray competing-risk regression was used to model the risk of VTE and ATE. Overall survival was analysed with Kaplan–Meier estimators. From 2003 to 2013, 1,469 patients with solid cancer (median age: 61 years; 47.3% female) were recruited and followed for 2 years. Overall, 128 (8.7%) patients developed VTE, 41 (2.8%) ATE and 643 (43.8%) patients died. The sub-distribution hazard ratios (SHRs) for VTE per doubling of PLR and NLR were 1.0 (95% confidence interval [CI]: 0.8–1.3, p = 0.899) and 1.2 (1.0–1.4, p = 0.059), respectively. For ATE, the SHR per doubling of PLR and NLR were 1.0 (0.7–1.5, p = 0.940) and 1.2 (0.9–1.6, p = 0.191), respectively. A higher PLR (hazard ratio [HR] per doubling = 1.5, 1.4–1.7, p < 0.001) and a higher NLR (HR per doubling = 1.5, 1.4–1.7, p < 0.001) were associated with an increased risk of mortality after adjusting for age, sex and cancer stage. There was no statistically significant association between NLR and VTE occurrence in patients with cancer. Neither PLR nor NLR were associated with the risk of ATE. Both elevated PLR and NLR were independently associated with a twofold increased risk of mortality.

Azidothymidine (AZT) in the Treatment of Symptomatic HIV-1-Infected Hemophiliacs

Twenty-one immunodeficiency virus 1 (HIV 1)-positive hemophilic patients were treated with Azidothymidine (AZT) for symptomatic HIV infection. The median observation period was 20.5 months.

At 25 months the probability of survival was 82%, the probability of progression of disease from CDC III or IV C2 to IV C1 (AIDS) was 20% in patients on continuous AZT treatment and 50% in patients with intermption of treatment. Three patients developed severe leukopenia and 3 patients severe anemii during AZT treatment. In 1 patient a dose-dependent striking increase of transaminases during AZT treatment was observed. In 7 patients treatment was intermpted, in 1 patient because of anemia, in 1 because of pruritus and in 5 patients because of noncompliance.

No signiticant changes in the consumption of clotting factor concentrates and number of bleeding episodes before and during AZT treatment were noted.

We conclude, that both hematological and non-hematological side effects of AZT in HIV 1-infected hemophilic patientr ur. comparable to those seen in other risk groups . AzT does not increase the bleeding tendency in this patient group.

Recurrent, Isolated Factor X Deficiency in Myeloma: Repeated Normalization of Factor X Levels after Cytostatic Chemotherapy Followed by Late Treatment Failure Associated with the Development of Systemic Amyloidosis

We describe the case of a 64-year-old woman with isolated severe factor X deficiency associated with kappa light chain myeloma. At the time of diagnosis there was no evidence for amyloidosis. Complete remission (CR) of myeloma as well as normalization of factor X levels were achieved after cytostatic chemotherapy. Subsequently, factor X deficiency recurred twice without any evidence for relapse of myeloma. The first time factor X normalized again following cytostatic treatment, the second time, however, factor X deficiency was refractory to chemotherapy. Finally, relapse of myeloma became evident associated with rapidly progressing, systemic amyloidosis, which was fatal within a few months. Initially, factor X infusion studies showed a normal recovery, but when amyloidosis became overt the recovery decreased to 0%. We assume that factor X deficiency was due to a binding of factor X to kappa light chains associated with the proliferation of the malignant myeloma cell clone.

Impaired efferocytosis by monocytes in multiple myeloma

Efficient clearance of apoptotic cells by efferocytosis is important for tissue homeostasis. Impaired efferocytosis leads to the accumulation of cell debris, which is regarded as a trigger in chronic inflammation and autoimmune diseases. Patients with hematological neoplastic disorders such as multiple myeloma (MM) exhibit high blood levels of apoptotic microparticles. The present study investigated whether these high levels of apoptotic microparticles are associated with insufficient dead cell clearance. Blood samples were collected from patients with MM immediately prior to and 3, 7 and 10 days after the initial cycle of bortezomib-based therapy. In addition, bone marrow aspirates (BMA) were collected prior to and following therapy. Prior to therapy, a 52% reduction in efferocytosis by blood monocytes was observed compared with the healthy controls (P<0.017). This was associated with an elevated number of 7-AAD⁺ dead cell remnants in the blood flow as well as in BMA. A portion of the blood samples contained active caspase 3. The subsequent bortezomib-based therapy had no effect on efferocytosis, although the quantity of dead cell remnants decreased. This reduction was associated with a decline in cluster of differentiation 8 (CD8)⁺ and CD4⁺ T cells and an increase in the number of monocytes. However, of 28 distinct soluble immune-modulating molecules (i.e. chemokines, cytokines and soluble co-stimulators) only C-C motif chemokine ligand 2 (CCL2), CCL24 and sCD27 were affected by bortezomib-based therapy. The levels of all other molecules remained unchanged or were below the detection threshold in all samples. The present study results revealed that the presence of dead cell remnants in the blood and bone morrow of patients with MM is associated with impaired efferocytosis by monocytes; however, its contribution to inflammatory events during MM remains unclear.

Association of mean platelet volume with risk of venous thromboembolism and mortality in patients with cancer

Venous thromboembolism (VTE) is a frequent complication in cancer patients. Mean platelet volume (MPV) has been associated with arterial and venous thrombosis in patients without cancer. We analysed MPV in cancer patients and investigated the association of MPV with risk of VTE and mortality. MPV was routinely determined in the Vienna Cancer and Thrombosis Study, a prospective, observational cohort study of patients with newly diagnosed or progressive cancer after remission. Study endpoints were occurrence of symptomatic VTE or death during a maximum follow-up of two years. Out of 1,544 included patients, 114 (7.4%) developed VTE and 573 (37.1%) died during a median observation time of 576 days. High MPV ≥75th percentile of the study population; ≥10.8 fL) was associated with decreased risk of VTE compared to MPV below the 75th percentile (HR [95% CI]: 0.59 [0.37–0.95], p=0.031). In multivariable analysis, including age, sex, cancer groups, newly diagnosed vs recurrent disease, platelet count and soluble P-selectin, this association remained statistically significant (0.65 [0.37–0.98], p=0.041). Mortality of patients with MPV (≥75th percentile was significantly decreased compared to those with lower MPV (0.72 [0.59–0.88], p=0.001). Two-year probability of VTE and overall survival was 5.5% and 64.7% in patients with high MPV compared to 9% and 55.7% in those with lower MPV. In conclusion, high MPV is associated with decreased VTE risk and improved survival in cancer patients. This finding is contrary to results observed in patients without cancer. Further studies are needed to confirm our results and elucidate underlying mechanisms.

Previous presentations of this manuscript: Data from this study were presented in part at the Annual Spring Meeting of the Austrian Society for Haematology and Oncology (OeGHO) in Linz, Austria, and as an oral presentation at the XXIV. Congress of the International Society on Thrombosis and Haemostasis (ISTH) 2013 in Amsterdam, the Netherlands.

Mortality in patients resuscitated from out-of-hospital cardiac arrest based on automated blood cell count and neutrophil lymphocyte ratio at admission

INTRODUCTION

The neutrophil lymphocyte ratio(NLR) is a marker of systemic inflammation. We hypothesized that admission NLR is related to mortality and that epinephrine application during resuscitation influences NLR in patients after successful resuscitation from out of hospital cardiac arrest (OHCA).

METHODS

This retrospective cohort study is based on a registry including all OHCA patients who had a presumed cardiac cause of cardiac arrest and achieved sustained ROSC prior to admission between 2005 and 2014. Patients were categorized into three groups according to the calculated NLR at admission (NLR <6, ≥6, and 'abnormal differential' indicating no differential blood cell count on patients report due to exceedance of machine predefined parameter limits). The primary outcome measure was long-term mortality after OHCA. Cox proportional hazards models were used for multivariable analysis.

RESULTS

Out of 2273 OHCA patients during the study period a total of 1188(52%) patients were eligible for analysis, of those 274(23%) were female and mean age was 64 (25-75 IQR:52-72). Compared to a NLR<6 (n=442), adjusted hazard ratio for long-term mortality was significantly higher in patients with a NLR≥6 (n=447; 1.52 (95%CI 1.03-2.24)) and in patients with abnormal differential (n=299; 3.16 (95%CI 2.02-4.97)). Epinephrine application during resuscitation did not explain the effect of NLR on mortality.

CONCLUSION

In this large retrospective cohort study of altogether >1000 OHCA patients, hospital admission NLR<6 compared to abnormal differential or NLR≥6 was associated with mortality independently from epinephrine application.

The oncogene EVI1 enhances transcriptional and biological responses of human myeloid cells to all-trans retinoic acid

The product of the ecotropic virus integration site 1 (EVI1) gene, whose overexpression is associated with a poor prognosis in myeloid leukemias and some epithelial tumors, regulates gene transcription both through direct DNA binding and through modulation of the activity of other sequence specific transcription factors. Previous results from our laboratory have shown that EVI1 influenced transcription regulation in response to the myeloid differentiation inducing agent, all-trans retinoic acid (ATRA), in a dual manner: it enhanced ATRA induced transcription of the RARβ gene, but repressed the ATRA induction of the EVI1 gene itself. In the present study, we asked whether EVI1 would modulate the ATRA regulation of a larger number of genes, as well as biological responses to this agent, in human myeloid cells. U937 and HL-60 cells ectopically expressing EVI1 through retroviral transduction were subjected to microarray based gene expression analysis, and to assays measuring cellular proliferation, differentiation, and apoptosis. These experiments showed that EVI1 modulated the ATRA response of several dozens of genes, and in fact reinforced it in the vast majority of cases. A particularly strong synergy between EVI1 and ATRA was observed for GDF15, which codes for a member of the TGF-β superfamily of cytokines. In line with the gene expression results, EVI1 enhanced cell cycle arrest, differentiation, and apoptosis in response to ATRA, and knockdown of GDF15 counteracted some of these effects. The potential clinical implications of these findings are discussed.

FLAG-induced remission in a patient with acute mast cell leukemia (MCL) exhibiting t(7;10)(q22;q26) and KIT D816H

Mast cell leukemia (MCL) is a life-threatening disease associated with high mortality and drug-resistance. Only few patients survive more than 12 months. We report on a 55-year-old female patient with acute MCL diagnosed in May 2012. The disease was characterized by a rapid increase in white blood cells and mast cells (MC) in the peripheral blood, and a rapid increase of serum tryptase levels. The KIT D816H mutation was detected in the blood and bone marrow (BM). Induction chemotherapy with high-dose ARA-C and fludarabine (FLAG) was administered. Unexpectedly, the patient entered a hematologic remission with almost complete disappearance of neoplastic MC and a decrease of serum tryptase levels to normal range after 2 cycles of FLAG. Consecutively, the patient was prepared for allogeneic stem cell transplantation. However, shortly after the third cycle of FLAG, tryptase levels increased again, immature MC appeared in the blood, and the patient died from cerebral bleeding. Together, this case shows that intensive chemotherapy regimens, like FLAG, may induce remission in acute MCL. However, treatment responses are short-lived and the overall outcome remains dismal in these patients. We propose to separate this acute type of MCL from more subacute or chronic variants of MCL.

EVI1 inhibits apoptosis induced by antileukemic drugs via upregulation of CDKN1A/p21/WAF in human myeloid cells

Overexpression of ecotropic viral integration site 1 (EVI1) is associated with aggressive disease in acute myeloid leukemia (AML). Despite of its clinical importance, little is known about the mechanism through which EVI1 confers resistance to antileukemic drugs. Here, we show that a human myeloid cell line constitutively overexpressing EVI1 after infection with a retroviral vector (U937_EVI1) was partially resistant to etoposide and daunorubicin as compared to empty vector infected control cells (U937_vec). Similarly, inducible expression of EVI1 in HL-60 cells decreased their sensitivity to daunorubicin. Gene expression microarray analyses of U937_EVI1 and U937_vec cells cultured in the absence or presence of etoposide showed that 77 and 419 genes were regulated by EVI1 and etoposide, respectively. Notably, mRNA levels of 26 of these genes were altered by both stimuli, indicating that EVI1 regulated genes were strongly enriched among etoposide regulated genes and vice versa. One of the genes that were induced by both EVI1 and etoposide was CDKN1A/p21/WAF, which in addition to its function as a cell cycle regulator plays an important role in conferring chemotherapy resistance in various tumor types. Indeed, overexpression of CDKN1A in U937 cells mimicked the phenotype of EVI1 overexpression, similarly conferring partial resistance to antileukemic drugs.

Performance Evaluation of the Sysmex XE-5000 Hematology Analyzer for White Blood Cell Analysis in Cerebrospinal Fluid

Context.—The newest generation hematology analyzer, Sysmex XE-5000 (Sysmex Corporation, Kobe, Japan) is equipped with an improved body fluid analysis mode.

Objective.—To evaluate the applicability of the XE-5000 analyzer to white blood cell (WBC) analysis in cerebrospinal fluid (CSF).

Design.—A total of 425 routinely collected, consecutive CSF samples were included in the study. For a comparison of total WBC counts, the results of routine chamber counts were grouped into categories of 0 to 5 (n  =  330), &gt;5 to 10 (n  =  36), &gt;10 to 50 (n  =  39), &gt;50 to 200 (n  =  15), and &gt;200 (n  =  5) WBC/µL. Microscopic differential counts were performed using cytospins from 276 samples. Results were grouped according to the percent content of polymorphonuclear (PMN) cells, 0% to 25% (n  =  263), &gt;25% to 50% (n  =  7), &gt;50% to 75% (n  =  3), and &gt;75% to 100% (n  =  3) of WBC. Corresponding results of XE-5000 analysis were matched to these particular count categories.

Results.—For total WBC counts, the proportions of samples correctly classified by the XE-5000 from the percentage groups described above were 88%, 47%, 72%, 93%, and 100%, respectively. After the two lowest count categories were combined into one range of 0 to 10 WBC/µL, matches increased to 95%. For PMN counts in the 0% to 25% group, 37% of samples were misclassified by the XE-5000. Conversely, for samples with microscopic PMN counts of more than 25%, there was a trend toward underestimation by the XE-5000. Mismatches were most pronounced in samples with fewer than 10 WBC/µL.

Conclusions.—The Sysmex XE-5000 hematology analyzer yields valid total CSF cell counts and may be considered an acceptable alternative to the traditional chamber method, even for samples with low WBC counts. However, it cannot be recommended as a suitable alternative for manual differential cytologic workup.

CD34(+)/CD38(-) stem cells in chronic myeloid leukemia express Siglec-3 (CD33) and are responsive to the CD33-targeting drug gemtuzumab/ozogamicin

BACKGROUND

CD33 is a well-known stem cell target in acute myeloid leukemia. So far, however, little is known about expression of CD33 on leukemic stem cells in chronic leukemias.

DESIGN AND METHODS

We analyzed expression of CD33 in leukemic progenitors in chronic myeloid leukemia by multi-color flow cytometry and quantitative polymerase chain reaction. In addition, the effects of a CD33-targeting drug, gemtuzumab/ozogamicin, were examined.

RESULTS

As assessed by flow cytometry, stem cell-enriched CD34(+)/CD38(-)/CD123(+) leukemic cells expressed significantly higher levels of CD33 compared to normal CD34(+)/CD38(-) stem cells. Moreover, highly enriched leukemic CD34(+)/CD38(-) cells (>98% purity) displayed higher levels of CD33 mRNA. In chronic phase patients, CD33 was found to be expressed invariably on most or all stem cells, whereas in accelerated or blast phase of the disease, the levels of CD33 on stem cells varied from donor to donor. The MDR1 antigen, supposedly involved in resistance against ozogamicin, was not detectable on leukemic CD34(+)/CD38(-) cells. Correspondingly, gemtuzumab/ozogamicin produced growth inhibition in leukemic progenitor cells in all patients tested. The effects of gemtuzumab/ozogamicin were dose-dependent, occurred at low concentrations, and were accompanied by apoptosis in suspension culture. Moreover, the drug was found to inhibit growth of leukemic cells in a colony assay and long-term culture-initiating cell assay. Finally, gemtuzumab/ozogamicin was found to synergize with nilotinib and bosutinib in inducing growth inhibition in leukemic cells.

CONCLUSIONS

CD33 is expressed abundantly on immature CD34(+)/CD38(-) stem cells and may serve as a stem cell target in chronic myeloid leukemia.

Immature and absolute platelet count changes and thrombocytopenia in malignant glioma

BACKGROUND

Temozolomide (TMZ) is commonly used for the therapy of malignant glioma and induces thrombocytopenia in a fraction of patients. Currently, no biomarkers predicting TMZ-induced thrombocytopenia are available. In this study, we investigated whether changes in platelet count (PLT) or the immature platelet fraction (IPF) may serve as predictor of TMZ-induced thrombocytopenia in malignant glioma patients.

METHODS

 We prospectively included 52 malignant glioma patients receiving TMZ-containing therapy regimens in this study. Platelet counts and IPF were determined at each clinical follow-up visit (weekly during concomitant radiochemotherapy or at least monthly during TMZ monotherapy) using the Sysmex XE-2100 system. We explored the diagnostic utility of PLT change/day and IPF change/day from the last to the current follow-up visit for the prediction of clinically relevant thrombocytopenia (PLT < 100·000 μl(-1) ) at the next follow-up visit.

RESULTS

Relevant thrombocytopenia was observed in 10 of 234 occasions. The areas under the receiver operating characteristic curves for PLT absolute change/day, PLT relative change/day and IPF relative change/day were 0·675, 0·703 and 0·663, respectively. The Youden indices (maximum sum of sensitivity and specificity minus one) were 0·31, 0·39, and 0·29, respectively. The corresponding positive predictive values were 16%, 57%, and 6·7%, and the negative predictive values were 97%, 97%, and 98%, respectively.

CONCLUSIONS

The rather moderate diagnostic potential of our data indicate that the time course of PLT counts and IPF measured at routine clinical follow-up are not useful for the prediction of thrombocytopenia in glioma patients treated with TMZ.

Idiopathic bone marrow dysplasia of unknown significance (IDUS): definition, pathogenesis, follow up, and prognosis

Minimal diagnostic criteria for myelodysplastic syndromes (MDS) include constant cytopenia recorded for at least 6 months, dysplasia, and exclusion of other causes of cytopenia and dysplasia. However, there are patients with dysplastic bone marrow features with or without a karyotype, who have only mild if any cytopenia. This condition has been termed idiopathic dysplasia of unknown significance (IDUS). Out of a series of 1,363 patients with suspected MDS or mild cytopenia seen between 1997 and 2010, we have identified 10 patients with IDUS, and analyzed their clinical course and outcome as well as features potentially involved in disease-evolution. Follow-up ranged between 2 and 13 years. Progression to an overt myeloid neoplasm was observed in 4 patients: two progressed to frank MDS, one to chronic myelomonocytic leukemia, and one to a myelodysplastic/myeloproliferative neoplasm exhibiting 5q-and JAK2 V617F. Consecutive studies revealed that most IDUS patients have an adequate production of erythropoietin (EPO) and sufficient numbers of EPO-responsive erythroid progenitors, features rarely seen in MDS. The erythropoiesis-promoting JAK2 mutation V617F was only detectable in one case. We hypothesize that the dysplastic clone in IDUS cannot manifest as frank MDS because i) the clone retains responsiveness against EPO, and ii) an adequate EPO-production counteracts anemia. Evolution of IDUS to low risk MDS may thus depend on the biological properties of the clone as well as patient-related factors such as EPO production. The latter often decreases with age and may thus explain why MDS often manifests in the elderly.

High platelet count associated with venous thromboembolism in cancer patients: results from the Vienna Cancer and Thrombosis Study (CATS)

BACKGROUND

In cancer patients, laboratory parameters that predict venous thromboembolism (VTE) are scarce. Increased platelet count has been found to be a risk factor for VTE in cancer patients receiving chemotherapy (CHT). We have assessed high platelet count as a risk predictor for VTE in patients with cancer undergoing discriminative anti-cancer treatments and investigated whether platelet count correlates with thrombopoietin (TPO) levels.

DESIGN AND METHODS

The Cancer and Thrombosis Study (CATS) is an ongoing prospective observational study of patients with newly diagnosed cancer or progression of disease, which started in October 2003. Occurrence of VTE and information on the patients' anti-cancer treatment during follow-up were recorded.

RESULTS

Between October 2003 and February 2008, 665 patients with solid tumors were included (314 female/351 male, mean age 62 years). VTE occurred in 44 patients (18 female/26 male, mean age 62 years). The cumulative probability of VTE after 1 year was 34.3% in patients with a platelet count (PC) above the 95th percentile representing 443 x 10(9)/L compared with 5.9% in those below 443 x 10(9)/L. High platelet count [hazard ratio (HR): 3.50, 95% confidence interval (CI): 1.52-8.06, P = 0.0032], soluble P-selectin [HR: 2.66, 95% CI: 1.42-4.96, P = 0.0021] and surgery [HR: 4.05, 95% CI: 1.74-9.46, P = 0.0012] were statistically significant risk factors for VTE in multivariable analysis along with leucocyte count, age, gender, radio- and CHT. We found no correlation between platelet count and TPO levels.

CONCLUSIONS

High PC is a clinically important, independent risk predictor for VTE in cancer patients. PC was not found to be associated with TPO levels.

Cardiac glycosides induce cell death in human cells by inhibiting general protein synthesis

BACKGROUND

Cardiac glycosides are Na(+)/K(+)-pump inhibitors widely used to treat heart failure. They are also highly cytotoxic, and studies have suggested specific anti-tumor activity leading to current clinical trials in cancer patients. However, a definitive demonstration of this putative anti-cancer activity and the underlying molecular mechanism has remained elusive.

METHODOLOGY/PRINCIPAL FINDINGS

Using an unbiased transcriptomics approach, we found that cardiac glycosides inhibit general protein synthesis. Protein synthesis inhibition and cytotoxicity were not specific for cancer cells as they were observed in both primary and cancer cell lines. These effects were dependent on the Na(+)/K(+)-pump as they were rescued by expression of a cardiac glycoside-resistant Na(+)/K(+)-pump. Unlike human cells, rodent cells are largely resistant to cardiac glycosides in vitro and mice were found to tolerate extremely high levels.

CONCLUSIONS/SIGNIFICANCE

The physiological difference between human and mouse explains the previously observed sensitivity of human cancer cells in mouse xenograft experiments. Thus, published mouse xenograft models used to support anti-tumor activity for these drugs require reevaluation. Our finding that cardiac glycosides inhibit protein synthesis provides a mechanism for the cytotoxicity of CGs and raises concerns about ongoing clinical trials to test CGs as anti-cancer agents in humans.

Inducible expression of EVI1 in human myeloid cells causes phenotypes consistent with its role in myelodysplastic syndromes

The oncogene EVI1 has been implicated in the etiology of AML and MDS. Although AML cells are characterized by accelerated proliferation and differentiation arrest, MDS cells hyperproliferate when immature but fail to differentiate later and die instead. In agreement with its roles in AML and in immature MDS cells, EVI1 was found to stimulate cell proliferation and inhibit differentiation in several experimental systems. In contrast, the variant protein MDS1/EVI1 caused the opposite effect in some of these assays. In the present study, we expressed EVI1 and MDS1/EVI1 in a tetracycline-regulable manner in the human myeloid cell line U937. Induction of either of these proteins caused cells to accumulate in the G₀/G₁-phase of the cell cycle and moderately increased the rate of spontaneous apoptosis. However, when EVI1- or MDS1/EVI1-expressing cells were induced to differentiate, they massively succumbed to apoptosis, as reflected by the accumulation of phosphatidylserine in the outer leaflet of the plasma membrane and increased rates of DNA fragmentation. In summary, these data show that inducible expression of EVI1 in U937 cells causes phenotypes that may be relevant for its role in MDS and provides a basis for further investigation of its contribution to this fatal disease.

Gene expression signature of chronic lymphocytic leukaemia with Trisomy 12

BACKGROUND

The prognosis of chronic lymphocytic leukaemia (CLL) patients is largely determined by the karyotype of the malignant clone. We have investigated the gene expression profile associated with trisomy 12 (+12).

DESIGN

Initially, unselected peripheral blood mononuclear cells of four patients with +12 were compared with 16 CLL controls using microarray analysis.

RESULTS

were validated by quantitative real-time PCR with RNA from 61 patients (29 with +12, 32 CLL controls). Results Seven genes showing the strongest correlation with +12 in microarray analysis were selected for real-time PCR: HIP1R, MYF6, SLC2A6, CD9 (overexpressed); CD200, P2RY14, RASGRP3 (underexpressed). Four genes were significantly associated with +12: HIP1R (P<0.0001), MYF6 (P=0.007), P2RY14 (P=0.014), CD200 (P=0.028). Receiver Operating Characteristic curve analysis revealed that HIP1R expression was a highly sensitive and specific marker for +12 in CLL patients. MYF6 was exclusively expressed in normal or malignant B cells in peripheral blood but was poorly predictive for +12. As expected, a number of overexpressed genes are located on chromosome 12 (HIP1R, MYF6). Interestingly, both significantly underexpressed genes (P2RY14, CD200) reside on the long arm of chromosome 3 pointing to trans-repression in this region.

CONCLUSIONS

Analysis of the molecular signature of trisomy 12 in CLL resulted in: (i) identification of a surrogate marker for PCR (HIP1R); (ii) observation of a gene dosage effect; and (iii) detection of specific underexpression of genes located on chromosome 3. These results should help to improve diagnosis and treatment decisions for patients with CLL and trisomy 12.

Dasatinib inhibits progenitor cell proliferation from polycythaemia vera

BACKGROUND

A mutation of Janus kinase 2 V617F is present in most patients with polycythaemia vera (PV). However, it is generally believed that JAK2(V617F) is not the sole molecular abnormality in PV. Since dasatinib is currently evaluated in patients with PV, it is of interest to study the effects of dasatinib on the growth of clonal progenitor cells in vitro.

DESIGN AND METHODS

Peripheral blood mononuclear cells from patients with PV, chronic myeloid leukaemia (CML) and controls were exposed to dasatinib (0.1 to 500 nm mL(-1)). Colony growth was stimulated by interleukin-3, granulocyte-macrophage colony-stimulating factor and erythropoietin. Endogenous erythroid colony (EEC) growth was investigated without exogenous cytokines. Real-time PCR was performed to assess the percentage of JAK2(V617F) cells.

RESULTS

10 nm of dasatinib suppressed EEC growth from PV by 89% (P = 0.002). This inhibition was dose dependent and occurred at pharmacological concentrations. Erythroid and myeloid colony growth was also significantly suppressed in the presence of exogenous cytokines. When compared to PV the inhibition of stimulated colony growth was significantly less pronounced in controls but tended to be more vigorous in CML. Interestingly, despite the potent inhibition of PV cells real-time PCR revealed that the numbers of JAK2(V617F) transcripts did not decrease upon exposure to dasatinib.

CONCLUSION

This study shows a marked inhibition of the proliferative capacity of progenitor cells from PV. Although JAK2(V617F) transcript levels did not decrease upon exposure to dasatinib, the drug might suppress PV progenitors through inhibition of a yet undefined molecular target.

Unique effects of KIT D816V in BaF3 cells: induction of cluster formation, histamine synthesis, and early mast cell differentiation antigens

Oncogenic tyrosine kinases (TK) usually convert growth factor-dependent cells to factor independence with autonomous proliferation. However, TK-driven neoplasms often are indolent and characterized by cell differentiation rather than proliferation. A prototype of an indolent TK-driven neoplasm is indolent systemic mastocytosis. We found that the D816V-mutated variant of KIT, a TK detectable in most patients with systemic mastocytosis, induces cluster formation and expression of several mast cell differentiation and adhesion Ags, including microphthalmia transcription factor, IL-4 receptor, histamine, CD63, and ICAM-1 in IL-3-dependent BaF3 cells. By contrast, wild-type KIT did not induce cluster formation or mast cell differentiation Ags. Additionally, KIT D816V, but not wild-type KIT, induced STAT5 activation in BaF3 cells. However, despite these intriguing effects, KIT D816V did not convert BaF3 cells to factor-independent proliferation. Correspondingly, BaF3 cells with conditional expression of KIT D816V did not form tumors in nude mice. Together, the biologic effects of KIT D816V in BaF3 cells match strikingly with the clinical course of indolent systemic mastocytosis and with our recently established transgenic mouse model, in which KIT D816V induces indolent mast cell accumulations but usually does not induce a malignant mast cell disease. Based on all these results, it is hypothesized that KIT D816V as a single hit may be sufficient to cause indolent systemic mastocytosis, whereas additional defects may be required to induce aggressive mast cell disorders.

Idiopathic cytopenia of undetermined significance (ICUS) versus low risk MDS: The diagnostic interface

It may sometimes be difficult to diagnose low risk MDS in patients with mild cytopenia. We report on 10 patients with mild to marked, unexplained cytopenia without definitive signs of a myeloid neoplasm. In two patients, a karyotype-abnormality (trisomy 14; monosomy 7) was detected in a small subset of bone marrow cells. Progression to overt MDS was seen in two patients including the one with monosomy 7. In the remaining cases, no MDS developed in a follow-up of at least 6 months. The phrase "idiopathic cytopenia of undetermined significance (ICUS)", as also suggested by Mufti and co-workers, is proposed and long term follow-up is recommended to assess the evolution.

Liposomal cytarabine for treatment of myeloid central nervous system relapse in chronic myeloid leukaemia occurring during imatinib therapy

BACKGROUND

Central nervous system (CNS) relapse in chronic myeloid leukaemia (CML) is rare and if recorded is usually found to occur in patients with lymphoblastic transformation. The BCR/ABL tyrosine kinase inhibitor imatinib is highly effective in patients with CML, but hardly crosses the blood-brain barrier.

PATIENTS AND METHODS

We report on two CML patients who developed a myeloid CNS relapse during treatment with imatinib. One patient was in major cytogenetic response at the time of CNS relapse. In both cases, the myeloid origin of neoplastic cells in the cerebrospinal fluid (CSF) was demonstrable by immunophenotyping, and their leukaemic origin by detection of the BCR/ABL oncoprotein. No BCR/ABL kinase domain mutations were found. Both patients received intrathecal liposomal cytarabine (50 mg each cycle; 6 cycles). In one patient, additional CNS radiation was performed, whereas in the other, consecutive treatment with dasatinib (70 mg per os twice daily) was started.

RESULTS

In response to therapy, the clinical symptoms resolved, and the leukaemic cells in the CSF disappeared in both cases. After three months of observation, both patients are in complete cytogenetic and major molecular response, without evidence for a systemic or a CNS relapse.

CONCLUSIONS

'Anatomic' resistance against imatinib in the CNS can lead to a myeloid CNS relapse. Liposomal cytarabine with or without radiation is effective as local therapy in these patients. For systemic treatment and prophylaxis, BCR/ABL kinase inhibitors crossing the blood-brain barrier such as dasatinib should be considered in patients with CNS relapse.

Endothelial progenitor cells in active rheumatoid arthritis: effects of tumour necrosis factor and glucocorticoid therapy

OBJECTIVES

To study the effects of short-term intermediate dose glucocorticoid (GC) therapy in patients with active rheumatoid arthritis (RA) on circulating endothelial progenitor cells (EPC), which are known to influence cardiovascular risk, and to elucidate mechanisms potentially responsible for the reduction of EPCs in patients with active RA.

METHODS

EPCs were quantified in 29 patients with active RA by flow cytometry, colony forming unit (CFU) and circulating angiogenic cell (CAC) assays before and after 7 days of intermediate dose GC therapy. CFU from patients with RA and from healthy referents (HR) were cultured in vitro in the absence or presence of dexamethasone (Dex) and/or TNF.

RESULTS

After 1 week of GC therapy, EPC increased from 0.026 (SD 0.003)% to 0.053 (SD 0.010)% (p<0.01), and from 12 (SD 4) to 27 (SD 7) CFU/well (p<0.02); CAC also increased from 7 (SD 2) to 29 (SD 8) cells/high power field (p<0.05). In parallel, disease activity decreased significantly after GC treatment. TNF serum levels also decreased from 36 (SD 10) to 14 (SD 6) pg/ml (p<0.0001). Addition of Dex to the RA CFU led to a significant increase of mean CFU counts, whereas addition of TNF induced a decrease of CFU.

CONCLUSIONS

Our data indicate that TNF may be at least partly responsible for the reduction of EPC seen in patients with RA. Intermediate doses of GCs for a short period of time, apart from reducing disease activity, significantly increase circulating EPC.