bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacological Targeting of Osteoblast-Induced MDS and AML
Authors: Mosialou Ioanna , Galan-Diez Marta , Vandenberg Andrew , Ali Abdullah Mahmood , Raza Azra , Kousteni Stavroula 
Published: October 2019

Abstract
The bone marrow hematopoietic stem cell niche has emerged as a regulator and instigator of hematological myeloid malignancies. Activation of b-catenin signaling in osteoblasts, by deletion of exon3 or by inactivating mutations in APC, induces myelodysplasia (MDS), rapidly progressing to acute myeloid leukemia (AML) in mice. Activated b-catenin signaling is present in osteoblasts of one third of MDS and AML patients and it is the most active pathway in stromal cells of MDS patients suggesting that it may sustain dysplastic hematopoiesis and progression to MDS and AML in humans. Therefore, targeting this pathway may provide a new therapeutic approach for this subgroup of MDS/AML patients. To examine this hypothesis we searched for an FDA-approved compound with the ability to inhibit b-catenin signaling and identified all-trans-retinoic acid (ATRA) as a potential candidate. We show here that treatment of osteoblastic cells with ATRA inhibits the induction of b-catenin target genes by Wnt3a and abrogates nuclear localization of b-catenin, as shown by immunohistochemistry and western blot analysis. These effects are at least in part independent of its phosphorylation by GSK3b on exon3 and are mediated by the retinoic acid receptor a (RARa) since silencing RARa, but not RARb or RARg, in osteoblasts abolishes the inhibitory effect of ATRA on Wnt3a-induced b-catenin signaling. Similarly, treatment of leukemic mice expressing constitutively active b-catenin in their osteoblasts with ATRA, inhibited b-catenin signaling as measured by expression of its target genes Axin2 and Lef1 in bone. At the same time, ATRA improved anemia and thrombocytopenia, decreased the percentage of blasts in bone marrow and blood and prolonged overall survival in these leukemic mice as compared to vehicle-treated mice. The response to ATRA treatment of two MDS patients with active b-catenin in their osteoblasts, and not responding to other treatments, was monitored. The hematologic phenotype of the patients improved and disease status stabilized so that patients remain transfusion independent and disease-related symptom-free with a good quality of life thereafter. The improvement in disease status coincided with absence of b-catenin in the nucleus as flow cytometry analysis showed a high percentage of patient osteoblasts expressing activated b-catenin in pre-therapy samples but not in on-therapy samples. These results suggest that ATRA may find a new use in the treatment of the specific portion of MDS/AML patients with activated b-catenin in their osteoblasts.

Disclosures
Raza: Geoptix: Speakers Bureau; Onconova: Research Funding, Speakers Bureau; Novartis: Speakers Bureau; Kura Oncology: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Syros: Research Funding.
Pomalidomide-Dexamethasone in the Management of Heavily Pretreated Multiple Myeloma
Authors: Cerchione Claudio , Nappi Davide , Pareto Anna Emanuele , Pane Fabrizio , Catalano Lucio 
Published: October 2019

Abstract
Background:
Pomalidomide is a new generation IMID, with a very good compliance, thanks to oral administration, which can be used also in heavily pretreated patients, in a domestic setting.
Aims:
In this retrospective observational trial, It has been evaluated efficacy and tolerance of pomalidomide plus dexamethasone (PD) as salvage regimen in heavily pretreated patients with relapsed and refractory MM (rrMM), whose prognosis is particularly severe.
Methods:
33 patients (19 M/14 F), with rrMM, median age at diagnosis 69 years (r. 52-84), and median age at start of treatment 76 years (r.56-89) treated with several lines of treatments (median 7, r. 2-11), every refractory to all the drugs previously received (also Bortezomib, Thalidomide and Lenalidomide), received Pomalidomide-Dexamethasone (Pomalidomide 4 mg for 21 days, Dexamethasone 40 mg days 1,8,15,22, pegfilgrastim day +8) every 28 days, until progression.
ISS was equally distributed, and cytogenetic was evaluable in 14 patients, and in particular three del13q and one t(11;14) were present. All the patients had previously been treated with schedule containing bortezomib and IMIDs. 60% (20/33) of them had undergone at least to a single ASCT.
All patients were relapsed and refractory to last therapies received before PD.
Results:
Pomalidomide was well tolerated, with grade 3 anemia in 51% (17/33) of patients, 36.3% (12/33) grade 3 neutropenia (pegfilgrastim in primary prophylaxis was given, no hospitalization was required, no septic shocks were observed), 30.3% (10/33) grade 3-4 thrombocytopenia without hemorrhagic events and transfusion-dependence. No severe extra-hematologic toxicity was observed.
According to IMWG, ORR1 (≥PR) was 45.4% (15/33: 4 CR, 5 VGPR, 6 PR), but, considering that we are evaluating a cohort of heavily pretreated patients without any other alternative treatment, with really poor prognosis, another parameter should be considered, ORR2 (≥SD), considering stable disease as a successful result in progressive MM. ORR2 was 78.7% (26/33: 4 CR, 5 VGPR, 6 PR, 11 SD). These can be considered as impressive result in this subset of patients.
Oral treatment gives a really good compliance, in frail and unfit patients, and response, when present, is always really fast (median time to response: 2 months (r.1-6)), median OS from diagnosis was 92 months (range 21-234), median OS from start of pomalidomide was 9 months (range 1-25).
Conclusions:
Pomalidomide-dexamethasone has shown significant efficacy and a very good compliance, thanks to oral administration, in a particularly severe setting of heavily pretreated patients, relapsed and refractory to all available therapeutic resources.

Disclosures
No relevant conflicts of interest to declare.
Adverse Outcomes in Concurrent Sickle Cell Disease and Hematological Malignancies
Authors: Perimbeti Stuthi Pavani , Hou Kevin Ye , Ramanathan Sabarina , Woodard Adonas , Kyung Daniel , Crilley Pamela Ann , Topolsky David , Ward Kristine , Styler Michael 
Published: October 2019

Abstract
Introduction:
Case reports have suggested that there is an increased risk of hematological malignancies with sickle cell disease (SCD). We aimed to investigate the prevalence and mortality of select hematological malignancies, including: acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), polycythemia vera (PV), essential thrombocytopenia (ET), Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL), primary myelofibrosis (PMF) in patients hospitalized with SCD.
Methods:
We queried the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample to identify the hospitalizations with SCD using ICD-9 codes 282.6, 282.60, 282.61, 282.62, 282.63, 282.64, 282.68, 282.69 from 1999 to 2014. Cases were then stratified based on the concurrent presence of the above hematological malignancies. The percentages of patients with each type of hematological malignancy were obtained using Chi-square analysis. In addition, we compared outcomes between patients with and without SCD who had hematological malignancies. Bivariate analysis for in-hospital mortality percentage was performed using Chi-square test. Multivariate analysis to evaluate the risk of death during hospitalization was performed using Cox proportional hazard regression with alpha set at 0.05.
Results:
There were 307,424 admissions (weighted=1,513,168) with SCD. Within these admissions, 0.04% (n=516) were associated with AML, 0.05% (n=720) with HL, 0.02% (n=47) with ALL, 0.07% (n=1,028) with NHL, 0.69% (n=10,654) with ET, 0.01% (n=20) with PMF and 0.01% (n=18) with PV. The hazard ratio for mortality (95% C.I.) with SCD compared to without SCD was 3.60 (1.24-4.67) for AML (p <0.001), 4.56 (2.78-6.78) for ET (p <0.001), 2.37 (1.41-5.67) for NHL (p=0.003), 1.5 (0.8-4.5) for HL (p=0.08), 1.1 (0.5-3.2) for ALL (p=0.04), 1.3 (1.1-3.2) for PMF (p= 0.03) and 1.7 (0.6-2.9) for PV (p=0.05).
Discussion:
The most frequently encountered hematological malignancy in patients with SCD was ET, followed by NHL and then HL. After controlling for multiple confounders including age, race, sex, comorbidities and socioeconomic status, the hazard of death during hospitalization with SCD, ET, AML, NHL and ALL are significantly higher compared to those without SCD.
While uncommonly encountered, concomitant hematological malignancy and SCD portends a significantly worse outcome, particularly in ET and AML. Potential explanations include iron overload from prior transfusions, increased infection risk due to asplenia and vascular damage from previous vaso-occlusive events. Newer advances in the management of SCD might improve subsequent outcomes in hematological malignancies.

Disclosures
No relevant conflicts of interest to declare.
The Role of LAMP5 in Innate Immune Signaling Is Critical for the Survival of MLL Leukemias
Authors: Gracia-Maldonado Gabriel , Clark Jason , Pierre Philippe , Mulloy James C. , Kumar Ashish R 
Published: October 2019

Abstract
Introduction
Chromosomal translocations involving the Mixed Lineage Leukemia (MLL, also called KMT2A) gene account for around 80% of the acute lymphoid leukemia (ALL) and 35%-50% of the acute myeloid leukemia (AML) diagnosed in infants, and are associated with poor outcomes. Despite improvements of conventional chemotherapies and treatments, patients with MLL-rearranged leukemia have weak response to treatment and poor prognosis. There is thus an urgent need to understand the molecular pathogenesis of these leukemias to develop more effective therapies. Gene expression studies show that MLL-leukemias uniquely display over-expression of Lysosome-associated Membrane Protein 5 (LAMP5) in both ALL and AML In normal hematopoiesis, LAMP5 expression is restricted to non-activated plasmacytoid dendritic cells (pDC), where it has been shown to be required for transport of TLR9 from VAMP3+/LAMP2+/LAMP1- endolysosomal vesicles to the LAMP1+ late lysosomal compartments, modulating the signaling and production of Type I interferon to TNF production. Here, we tested the hypothesis that LAMP5 is required for MLL leukemia wherein it modulates innate immune signaling.
Methods and Results
In previous studies, we found LAMP5 expression being restricted to MLL-fusion leukemia cell lines. Additionally, in an inducible model, LAMP5 expression directly correlated with that of the MLL-fusion protein MLL-AF9. . Knockdown on LAMP5 in MLL-fusion leukemia cells inhibited their propagation both in vitro and in vivo whereas the non-MLL leukemias were unaffected. To determine the mechanisms by which LAMP5 promotes growth in MLL leukemias, first we studied the localization of LAMP5 in these cells. Using immunofluorescent confocal microscopy we detected LAMP5 mainly in LAMP2+/LAMP1+ compartments. Additionally, LAMP5 co-localized with MYD88, a known scaffold protein required for IL1R/TLR signaling. Accordingly, LAMP5-knockdown abrogated TLR signaling as evidenced by reduced activation of JNK, MAPK p38, IRF7 and NFKB. Conversely, over-expression of LAMP5 in the non-MLL leukemia cell line Kasumi-1 led to increased activation of JNK, p38, IRF7 and NFKB, indicating that the innate-immune signaling pathway is regulated by LAMP5 expression in leukemias.r
Conclusions
Collectively, these results demonstrate that LAMP5 is required for the survival of MLL leukemia and that it plays an important role in the activation of the IL1/TLR signaling pathway. Overall, based on our results and the limited expression in normal hematopoiesis, we propose that LAMP5 could potentially serve as a therapeutic target with a wide therapeutic-window to treat MLL-leukemias.

Disclosures
No relevant conflicts of interest to declare.
Identification of GBA Gene Mutations in 19 Pakistani Unrelated Patients of Gaucher Disease
Authors: Naz Arshi , Abedin Qurat , Ahmed Shariq , Siddiqui Saima , Shamsi Tahir 
Published: October 2019

Abstract
Introduction: Gaucher disease (GD) is one of the lysosomal storage diseases that is rare and inherited autosomal recessively. There is insufficiency of glucocerebrosidase enzyme that leads to the build up of un-degraded substrates in white blood cells causing anemia, hepatosplenomegaly and skeletal disease. This enzyme deficiency is linked with the defect of its gene (GBA) that codes for this enzyme. Initial diagnosis is made by the estimation of glucocerebrosidase level in blood and confirmed by genetic analysis of GBA gene. To identify the mutations of GBA gene in Pakistani patients with GD from different regions of Pakistan.
Sampling & methodology: The sample and demographic data was collected in National Institute of Blood Disease and Bone marrow Transplantation after approval of IRB and written informed consent of patients. We collected total 19 blood samples, out of which 5 had Gaucher's disease, 10 samples were parents of the index cases and 4 were control. The methodology consisted of DNA extraction and quantification from peripheral blood. Genetic analysis of coding regions of GBA gene was done via gene amplification, gel electrophoresis and sequencing.
Result: Mutation was found in two out of five families that makes the prevalence of GBA gene mutation 40%. These were diagnosed on reduced enzyme levels and found to have L444P (c.1448T>C) mutation in homozygous form in 10th exon of GBA gene. The parents of that patient carried the same mutation in one allele. Rest of the patients who were diagnosed on bone marrow morphology showed no mutation in GBA gene.
Conclusion: Our results illustrate that GBA gene mutation was found in those patients who were diagnosed by the estimation of β-glucosidase enzyme levels rather than on bone marrow morphology. In our population, the mutation L444P was found, which is the most frequent gene mutation found in the world. Since this study is conducted in a small number of patients therefore it is recommended that large cohorts of patients should be evaluated in future for genetic mutations among Gaucher's patients in Pakistan
Key words: Gaucher disease, storage disorder, GBA gene

Disclosures
No relevant conflicts of interest to declare.
Effects of intravenous immunoglobulin on platelet count and antiplatelet antibody disposition in a rat model of immune thrombocytopenia
Authors: Hansen Ryan J. , Balthasar Joseph P. 
Published: October 2019

Abstract
Experiments were conducted to investigate the effects of intravenous immunoglobulin (IVIG) in a rat model of immune thrombocytopenia (ITP). Rats were pretreated with 0 to 2 g/kg IVIG and then challenged with an antiplatelet antibody (7E3, 8 mg/kg). IVIG effects on 7E3-induced thrombocytopenia and on 7E3 pharmacokinetics were determined. IVIG pretreatment led to significant changes in the degree and time-course of 7E3-induced thrombocytopenia (P = .031). Nadir percent platelet counts were 121% to 279% greater in animals treated with IVIG (0.4-2 g/kg) than in animals receiving 7E3 alone. IVIG treatment also led to dose-dependent increases in 7E3 clearance (P < .001), with more than 2-fold increases in 7E3 clearance seen following the highest dose of IVIG. In vitro experiments showed that IVIG effects on platelet count are not likely due to anti-idiotypic inhibition of 7E3-platelet binding and that IVIG did not directly bind to 7E3. Consequently, IVIG-7E3 binding cannot explain the increase of 7E3 clearance following IVIG treatment. We propose that the observed increase in 7E3 clearance with IVIG therapy is due to saturation of the FcRn salvage receptor for IgG. The importance of the effect of IVIG on 7E3 clearance to the prevention of thrombocytopenia in these animals is unclear at present; nonetheless, these data provide experimental support for a new mechanism of IVIG action in ITP (ie, IVIG-mediated increases in antiplatelet antibody elimination). This model of ITP will be useful for further investigations of IVIG mechanism of action and for development of new therapies for ITP.
A prospective study on the evolution of the T-cell repertoire in patients with Sézary syndrome treated by extracorporeal photopheresis
Authors: Ingen-Housz-Oro Saskia , Bussel Annette , Flageul Béatrice , Michel Laurence , Dubertret Louis , Kourilsky Philippe , Gachelin Gabriel , Bachelez Hervé , Musette Philippe 
Published: October 2019

AbstractSézary syndrome is a leukemic form of epidermotropic cutaneous T-cell lymphoma related to the malignant proliferation of clonal CD4+ T cells. Extracorporeal photochemotherapy may induce a transient improvement of the clinical signs, but its efficiency is discussed. To investigate the frequency of the T-cell clone in the peripheral blood of patients with Sézary syndrome and to monitor its evolution in patients treated using extracorporeal photopheresis or chemotherapy, we used the immunoscope technique. In one patient, we observed a decrease of the relative frequency of the clone from 15.6% to 0%, paralleling a complete remission of the clinical disease and a disappearance of the circulating Sézary cells. In the other cases, the evolution of the relative frequency paralleled the initial improvement of the clinical status and the absence of long-term efficiency in patients treated with extracorporeal photopheresis or chemotherapy. We observed a quick-acting direct cytotoxicity of the association 8MOP + UVA on the T-cell clone. The immunoscope technique appears to be an efficient tool to appreciate the amount of tumoral cells and to monitor the evolution of the clonal component in the Sézary syndrome.
Recombinant Factor VIIa Enhances Platelet Adhesion and Aggregation under Flow Conditions at Normal and Reduced Platelet Count.
Authors: Lisman Ton , Adelmeijer Jelle , Cauwenberghs Sandra , van Pampus Elisabeth C.M. , Heemskerk Johan W.M. , de Groot Philip G. 
Published: October 2019

Abstract
Recombinant factor VIIa (rFVIIa) has been developed for treatment of inhibitor-complicated hemophilia. Increasing clinical evidence shows that rFVIIa also appears safe and effective as pro-hemostatic agent in various other clinical disorders including patients with thrombocytopenia. Relatively little is known about the mechanism of action of rFVIIa in hemophilia and its various other potential indications. It is generally accepted that rFVIIa functions by enhancement of thrombin generation at the site of injury. It is, however, unknown if and how this affects platelet adhesion and aggregation. Previously, we have shown that rFVIIa-mediated thrombin generation substantially enhances deposition of platelets from patients with Glanzmann thrombasthenia (a qualitative or quantitative deficiency of the integrin αIIbβ3) to subendothelial proteins (Blood2004, 103: 1720). Here, we investigated the effect of rFVIIa-mediated thrombin generation on platelet adhesion and aggregation under flow conditions at normal and reduced platelet count. A mixture of washed platelet and red cells was perfused over collagen or fibrinogen in presence or absence of a thrombin-generating system consisting of purified coagulation factors rFVIIa, X, and prothrombin in the presence of calcium chloride. Addition of this thrombin-generating system enhanced platelet adhesion and aggregation to collagen and adhesion and spreading to fibrinogen at normal platelet count and at platelet numbers as low as 10.000/μl. rFVIIa-mediated thrombin generation enhanced the activation state of platelets adhered under flow as measured by intracellular calcium fluxes, and enhanced the exposure of procoagulant phospholipids as measured by annexin A5 binding. It was shown that FITC-labeled rFVIIa bound to collagen-adhered platelets under flow conditions in experiments in which whole blood from severely thrombocytopenic patients was used. We believe thrombin is generated by platelet-bound rFVIIa independent of tissue factor. Taken together, increased platelet adhesion and aggregation by rFVIIa-mediated thrombin formation may explain the therapeutic effects of rFVIIa in thrombocytopenic conditions and in patients with a normal platelet count by (1) enhancement of primary hemostasis and (2) enhancement of procoagulant surface leading to elevated fibrin formation. These platelet-promoting effects of rFVIIa might also, in part, explain the therapeutic effects of rFVIIa in other indications.
Rhesus Box Variation: Multiple RHD Deletion Events and Implications for Testing RHD Heterozygosity.
Authors: Flegel Willy A. , Moulds Joann M. , Wagner Franz F. 
Published: October 2019

Abstract
The RHD gene encoding the Rhesus blood group antigen D is flanked by two highly homologous DNA segments of about 9,000 bp, the upstream and downstream Rhesus boxes. In haplotypes with an RHD deletion, the fusion of the two Rhesus boxes within the 1,463 bp identity region generates the single hybrid Rhesus box. Its detection has been applied to determine RHD zygosity. For instance, testing for RHD heterozygosity is of clinical interest, because all children of an RHD homozygous father will be D positive and at risk of hemolytic disease of the newborn, if the mother carries an anti-D. Aberrant Rhesus boxes can confound this application and appear to be frequent among Africans. A comprehensive, systematic analysis was lacking. We sequenced about 5,850 bp of the upstream and downstream Rhesus boxes in 18 samples that were representative for all four D clusters and of the hybrid Rhesus box in 4 samples that were mistyped in assays for the hybrid Rhesus box. The known differences between upstream and downstream Rhesus boxes were in part restricted to subsets of RHD alleles. We detected 46 additional polymorphism, which represented single nucleotide substitutions, short insertions or deletions. Gene conversions were found in the upstream Rhesus boxes of RHDψ, DAU-1 and DAU-3 and in the downstream Rhesus boxes of Ccdes, weak D type 4.1, type 4.2 and DAU-0. All 6 different gene conversions started or ended in or near the identity region, which may have been instrumental for generating these gene conversions. Recombinations between haplotypes were likely in several alleles like DIII type 4. Four non-standard hybrid Rhesus boxes were suggestive of multiple independent RHD deletion events.
We found considerable variation of Rhesus box sequences, which explained the limitations for RHD heterozygosity testing that were previously observed in several laboratories. The general topology of the genomic Rhesus locus was however similar in all cases and consistent with our initial description. There was evidence for 5 probably independent RHD deletion events. Testing RHD heterozygosity in Africans is best based on quantitative PCR or amplification of the full length hybrid Rhesus box. Because in Europeans who harbored RHD alleles belonging to African D clusters the Rhesus box variation was also substantial, use of two complementary methods for hybrid Rhesus box detection may even be advisable in whites. We conclude that a long range PCR spanning the whole hybrid Rhesus box, while technically demanding, is not influenced by the kinds of aberrations observed in this study and may hence remain the standard for research purposes and quality assurance.