bluuebunny/crossref_metadata_2025_split huggingface dataset:
The TAL1 Short Isoform Generated By PRMT1-Mediated Alternative RNA Splicing Promotes Erythroid Differentiation
Authors: Jin Shuiling , Tran Ngoc-Tung , Su Hairui , Huang Suming , Zhao Xinyang , Liu Yanyan 
Published: October 2019

Abstract
The isoforms of key transcription factors in hematopoiesis such as TAL1, GATA1 and RUNX1 are generated through alternative RNA splicing regulated by the PRMT1-RBM15 axis (Zhang et al. 2015). The functions of short isoforms of GATA1 (GATA1s) and RUNX1 (RUNX1a) are well characterized, yet it is unknown how the short isoform of TAL1 (TAL1s) regulates hematopoiesis. In this presentation, we report that the short isoform of TAL1, i.e. TAL1s, is generated via alternative RNA splicing as detected by isoform specific real-time PCR reactions using RNA isolated from leukemia cell lines and primary human cord blood cells. RBM15, an RNA binding protein, which is involved in chromosome translocation to produce RBM15-MKL1 fusion protein in acute megakaryocytic leukemia, regulates the alternative RNA splicing of TAL1. RBM15 promotes the production of full-length TAL1 mRNA, while reduction of RBM15 protein level via PRMT1-mediated degradation pathway favors the production of TAL1s. RBM15 directly binds to intronic regions on TAL1 pre-mRNA. Binding of RBM15 is responsible for recruiting SF3B1-associated RNA splicing complex. Given that PRMT1 senses the hypoxia status of hematopoietic cells, the changing of TAL1s/TAL1fl ratio by PRMT1 activity may be an adaptive response of hematopoietic cells to hypoxia status. The short form TAL1s still contains the helix-loop-helix DNA binding domain but not the N terminal regions upstream of the DNA binding domain. Thus, the TAL1s may act as a dominant negative mutant of the full-length TAL1fl to block TAL1fl-regulated transcription. We demonstrated that overexpression of TAL1s not the full-length TAL1promotes the erythroid differentiation of K562 cells. Although TAL1 gene is required for both erythroid and megakaryocyte differentiation at early stage of hematopoiesis, TAL1s does not promote megakaryocyte differentiation. Therefore, fine-tuning the TAL1 isoforms by the PRMT1-RBM15 axis determine the cell fate of a MEP progenitor cell. Using immunoprecipitation assays and mass spectrometry analysis, we identified proteins specifically associated with the N terminal region of TAL1. How unique TAL1s-associated transcriptional regulatory complex plays in erythroid differentiation will be discussed in the presentation in comparison with the Tal1fl-asociated protein complex. In summary, our findings stratify another new layer of regulation by PRMT1, which relays extracellular signals (such as hypoxia signal) to transcriptional regulatory program. Given that PRMT1 is often constitutively highly expressed in leukemia cells, how overproduction of short form TAL1 interferes with normal hematopoiesis may help to explain the molecular mechanisms of many hematological malignancies associated with dysregulation of TAL1 expression.

Disclosures
No relevant conflicts of interest to declare.
Universal Screening for G6PD Deficiency Detects More Cases Than Selective Testing
Authors: Segal Ilan , Aviner Shraga , Abu Rmaileh Ashraf , Cohen Ornit , Sayag Avraham , Zangen Shmuel 
Published: October 2019

Abstract
Background: Testing for glucose-6-phosphate dehydrogenase (G6PD) deficiency is traditionally restricted to jaundiced neonates, as well as to those whose risk factors provide sufficient grounds to suspect the deficiency. We assumed that in a multi-ethnic, multicultural society, routine neonatal screening for G6PD deficiency would detect more affected neonates.
Methods: An observational, population-based, cohort study was designed to compare the incidence of G6PD deficiency between two groups of neonates using a validated qualitative enzyme test. Incidence of G6PD deficiency was calculated retrospectively for one group of neonates born between January 2005 and July 2012 (i.e., epoch 1), when only "at-risk" newborns were tested for the deficiency (i.e., group 1). Incidence was also calculated for a second, prospective group of neonates, who were all to be born between August 2012 and April 2014 (i.e., epoch 2), and were all screened for the deficiency irrespective of risk factors.
Results: A total of 39,268 live-born infants were included in our study. In epoch 1, 6.8% of all newborns were tested for the deficiency, compared to about 87% in epoch 2. The incidence of G6PD deficiency was 0.4% (119/29,332) and 1.6% (156/9,936) in epoch 1 and epoch 2, respectively (p<0.05). Among females, there was a 6.6-fold increase in incidence of G6PD deficiency between epoch 1 (0.08% [12/14,410]) and epoch 2 (0.53% [26/4,881]), while among males there was a 3.4-fold increase in incidence between epoch 1 and epoch 2 (0.72% [107/14,922] and 2.47% [125/5055], respectively).
Conclusions: As universal screening for G6PD deficiency detects more affected newborns than the selective, risk-factor-based testing does, we suggest that validation of our study and cost-effectiveness analyses may further the aim of introducing universal screening for G6PD deficiency for neonates born in multi-ethnic, multicultural society setting.

Disclosures
No relevant conflicts of interest to declare.
ANX005, an Inhibitory Antibody Against C1q, Blocks Complement Activation Triggered By Cold Agglutinins in Human Disease
Authors: Gertz Morie A. , Qiu Haiyan , Kendall Laura , Saltarelli Mario , Yednock Ted , Sankaranarayanan Sethu 
Published: October 2019

Abstract
Cold agglutinin disease (CAD) is an autoimmune hemolytic anemia characterized by the presence of autoantibodies (cold agglutinins) that bind to red blood cells (RBC) at low temperatures. Cold agglutinin binding to RBCs results in antibody-mediated classical complement activation with deposition of complement C4 and C3 fragments onto the RBC surface. Complement-opsonized RBCs are removed from the circulation by macrophage-driven phagocytosis in the liver or spleen and via intravascular hemolysis following assembly of the terminal lytic complex (C5b - C9), together resulting in clinical anemia.
C1q is the initiating molecule for cold agglutinin-mediated complement activation on the surface of human RBCs. We hypothesized that directly blocking C1q recruitment onto cold agglutinin-sensitized RBCs will prevent complement activation and opsonization and reduce hemolysis. To this end, we have developed a humanized monoclonal antibody (ANX005) that binds with high-affinity (~10 pM) to C1q and blocks classical complement activation & hemolysis in an in vitro sheep RBC assay. We evaluated the impact of ANX005 on hemolysis and complement deposition on human RBCs that were pre-sensitized with sera from CAD subjects. ANX005 showed a dose-dependent reduction in hemolysis using both individual and pooled CAD sera as the source of cold agglutinin. We further demonstrated that C1q blockade led to a robust reduction in C4 and C3 fragment deposition onto human RBCs. These results demonstrate that C1q inhibition is an effective way to impede C4 and C3 activation and downstream assembly of the lytic complex in sera from CAD patients, and support the clinical development of ANX005 in CAD and other antibody-mediated diseases.

Disclosures
Gertz: Prothena Therapeutics: Research Funding; Sandoz Inc: Honoraria; NCI Frederick: Honoraria; Celgene: Honoraria; Med Learning Group: Honoraria, Speakers Bureau; Research to Practice: Honoraria, Speakers Bureau; Alnylam Pharmaceuticals: Research Funding; Novartis: Research Funding; Ionis: Research Funding; Annexon Biosciences: Research Funding; GSK: Honoraria. Qiu:Annexon Biosciences: Employment, Equity Ownership. Kendall:Annexon Biosciences: Employment, Equity Ownership. Saltarelli:Mallinckrodt: Equity Ownership; Abbvie: Equity Ownership; Annexon Biosciences: Employment, Equity Ownership, Patents & Royalties. Yednock:Annexon, Inc: Employment, Equity Ownership. Sankaranarayanan:Annexon Biosciences: Employment, Equity Ownership.
The Impact of a Multidisciplinary Sickle Cell and Gynecology Clinic
Authors: Tasha Vardya A 
Published: October 2019

Abstract
Background: Contraception and pregnancy planning are critically important for patients with sickle cell disease (SCD). However, rates of contraceptive utilization are often suboptimal and unplanned pregnancy remains a problem among this patient population. In an effort to improve care, a multidisciplinary hematology and gynecology clinic was initiated at University Hospitals Case Medical Center in which women of reproductive age received comprehensive care in single visits.
Objective: To determine the impact on pregnancy, contraception use and sexually transmitted infections (STIs) diagnoses of a multidisciplinary hematology and gynecology clinic for women with SCD.
Methods: A retrospective cohort study of women seen in University Hospitals Hematology Clinic for sickle cell disease from 2011 to 2015. Baseline demographics as well as the subsequent outcomes of pregnancies, contraception use and STIs were collected. Total differences in outcomes before and after the multidisciplinary clinical were evaluated with Fisher's exact test. Longitudinal differences in pregnancies and STIs were analyzed with time-to-event analyses. For outcomes of interest p charts were constructed with upper and lower control limits.
Results: A total of 133 women total were identified as reproductive age women with sickle cell disease from 2011 to 2015. The percentage of SCD patients using birth control before and after the multidisciplinary clinic increased from 12.3% to 37% (p=0.0001). The p chart for contraception use is provided bellow and was highly significant. No significant differences in pregnancy or STIs were identified in time-to-event analysis and p charts, though the total number of STIs before and after the intervention was limited (eighteen).
Conclusion: Incorporating a multidisciplinary approach with combined hematology and gynecology care for women with sickle cell disease has the potential to improve access to contraception use in this population.
Figure Figure.

Disclosures
No relevant conflicts of interest to declare.
Clinical and Biological Determinants of Bleeding Manifestation in Congenital Factor XI Deficiency; A Systematic Review
Authors: Drakulic Milana , Chai-Adisaksopha Chatree , Iorio Alfonso 
Published: October 2019

Abstract
Background: Congenital factor XI (FXI) deficiency is a rare inherited bleeding disorder caused by mutation of the FXI gene. Clinical manifestation and bleeding severity of FXI deficiency are varied. To our best knowledge, there are no studies investigating the predictors of bleeding in these patient population. Our study aims to investigate the clinical presentation of congenital FXI deficiency and to identify clinical, biological, and genetic determinants of bleeding.
Methods: We conducted a systematic search in MEDLINE and EMBASE databases from inception to March 2016. We included the studies of congenital FXI deficiency. In terms of study design, we included prospective or retrospective studies as well as case series and case reports. We collected clinical characteristics of the patients including age, sex, family history of FXI deficiency, family history of bleeding, and site of bleeding. We also collected the laboratories including baseline aPTT, FXI level, and genetic test results.
Results: There were 141 studies included in this review, involving 728 patients with reported congenital FXI deficiency. Forty-three percent of the patients were male. Clinical characteristics of the patients was demonstrated in Table 1. Of these, 421 (51.84%) patients had bleeding tendency. Surgical bleeding was the most common bleeding manifestation (31.88%), following bymucocutaneous bleeding (13.35%) and hypermenorrhea (9.11%). Factor XI gene mutation was found in 422 patients (57.97%). Type II mutation was the most common reported mutation (45.19%). With regards tozygosity of patients with gene mutation, 43.94% of patients had heterozygosity of factor XI gene mutation. Univariate analysis revealed that patients with baseline factor XI level less than 25% were associated with higher risk of bleeding (odd ratio 1.48 (95% confidence interval [CI]; 1.05 to 2.09). In addition, patients with combined mutation were at higher risk of bleeding when compared to patients with single mutation (odd ratio 2.83 (95% CI; 1.09-7.39).
Conclusion: Our study found that patients with factor XI deficiency has mild bleeding manifestation. Half of the patients do not experience bleeding tendency. Surgical bleeding is the most common presentation in these patient population and likely to be the first bleeding symptom. Baseline factor XI level less than 25% is the predictor of bleeders as well as combined gene mutation.
Table 1 Characteristics of patients with congenital factor XI deficiency Table 1. Characteristics of patients with congenital factor XI deficiency

Disclosures
No relevant conflicts of interest to declare.
HSP27: A Therapeutic Target in Myelofibrosis
Authors: Sevin Margaux , Pernet Nicolas , Vitte Franck , Ramla Selim , Sagot Paul , Martin Laurent , Villeval Jean Luc , Lacout Catherine , Plo Isabelle , Garrido Carmen , Girodon Francois , de Thonel Aurelie 
Published: October 2019

Abstract

Myelofibrosis (MF) is the most aggressive myeloproliferative neoplasms (MPN) with the highest degree of morbidity and mortality, including progressive bone marrow fibrosis resulting into bone marrow failure. JAK2 kinase inhibitors have been successfully used for a few years in MPN and more particularly for MF treatment. Despite their beneficial effects on spleen size and symptoms, JAK2 inhibitors induce low molecular and survival responses underscoring the urgent need for other therapeutic approaches. Recently, heat shock protein 90 (HSP90) - known to stabilize JAK2 - has been reported as a promising therapeutic target in MPN. However HSP90 inhibitors show toxicity and induce the expression of stress-inducible proteins like HSP70 and, most likely HSP27 as previously shown in other cancers. In addition, we and others have shown that HSP27, was strongly expressed in patients with idiopathic pulmonary, lung or kidney tubulointerstitial fibrosis, underlying a relevant role of HSP27 in fibrotic processes. Taking into account both the beneficial effects of HSP inhibitors in leukemia and in MPN, and the possible implication of HSP27 in fibrosis, we have evaluated in this work, the status of HSP27 in MF patient's samples and assess the effectiveness of an HSP27 oligonucleotide inhibitor called OGX-427.
In this study, we first assessed the extracellular and intracellular level of HSPs from MF patients by ELISA, flow cytometry and by immunohistochemistry. We observed for the first time a specific increase in both intracellular and extracellular HSP27 in CD34+ circulating hematopoietic progenitor cells (n=9-16; P=0.0097) and in the sera of patients (n=24-27; P<0.0001) with MF compared with healthy donors, respectively. Moreover, we identified the presence of HSP27 in the bone marrow's MF patients.
We then investigated the in vivo impact of OGX-427, a specific inhibitor of HSP27, or an oligonucleotide control in a murine TPO-induced MF mouse model. The use of OGX-427 limited the progression of the disease in our MF mouse model (n=9). In particular, OGX-427 was associated with a marked reduction in both the spleen weight and size. Also, we noted a decrease of megakaryocyte hyperplasia in the bone marrow accompanied by a visible restoration of spleen structure and lymphoid white pulp territories with OGX-427.
Taking altogether, our results support a key role of HSP27 in the pathophysiology in MF and highlight the potential therapeutic benefit of HSP27 inhibitors in this disorder.

Disclosures
No relevant conflicts of interest to declare.
Antithymocyte Globulin-Based Prophylaxis for Graft Versus Host Disease Compared to Post-Transplant Cyclophosphamide-Based Prophylaxis in Matched Unrelated Donor Transplantation
Authors: Redondo Velao Sara , Kwon Mi , Champ Diana , Pascual Cascon MJ , Balsalobre Pascual , Diez J , Vidales Mancha I , Serrano David , Fernandez Noemi , Anguita Javier , Buño Ismael , Gayoso Jorge , Diez-Martin Jose Luis 
Published: October 2019

Abstract
INTRODUCTION
Post-transplant high-dose cyclophosphamide (PTCy) has shown to prevent graft versus host disease (GvHD) after haploidentical allogeneic hematopoietic cell transplantation (HSCT). Although less extended, its use after matched unrelated donor (MUD) HSCT in combination with additional immunosuppression has been encouraging. The aim of this study was to analyze and compare outcomes of antithymocyte globulin based (ATG) versus PTCy-based GvHD prophylaxis in matched unrelated donor HSCT.
MATERIAL AND METHODS
We retrospectively analyzed 51 MUD (8/8 HLA-matched) transplants performed in two Spanish centers: 25 received ATG-based prophylaxis and were performed from 2010 to 2013, and 26 received PTCy-based prophylaxis and were performed from 2013 to 2016.
RESULTS
Characteristics of patients and post-HSCT complications are detailed in Table 1. There were no significant differences in age, gender, diagnosis and Disease risk index. For the ATG group, conditioning regimen consisted of fludarabine combined with busulfan (80%) or melphalan (12%), and TBI plus cyclophosphamide (8%). All patients received ATG 2 mg/kg from day -4 to day -2 followed by methotrexate and cyclosporine (CsA). Conditioning regimen for patients from the PTCy group consisted of fludarabine and busulfan (85%) and thiotepa combined with busulfan and fludarabine (15%). GvHD prophylaxis consisted of PTCy 50 mg/kg on days +3 and +4, combined with: CsA plus MMF in 57%, CsA alone in 31%, or tacrolimus plus MMF or sirolimus in 8%, and tacrolimus alone in 4%.
With a median follow-up of 58 months for the ATG group and 12 months for the PTCy group, there were no statistically significant differences in overall survival at 18 months (56% vs 85%, p=0.08), in event free survival (56% vs 68%, p=0.5), and in cumulative incidence of relapse (12% vs 18%, p=0.3). Non-relapse mortality at 12 months was significantly higher in the ATG group (32% vs 10%, p = 0.04). The ATG group presented more cases of hepatic toxicity grades I-IV and hemorrhagic cystitis than PTCy group (Table 1). Cumulative incidence of acute GvHD grades II-IV was higher in the ATG group as well as acute GvHD grades III-IV, with no differences in moderate/severe chronic GvHD incidence (Figure A).
CONCLUSION
In our experience, albeit differences in follow-up and limited number of patients, we conclude that PTCy combined with additional immunosuppression after MUD allogeneic HSCT offers lower rates of acute GvHD together with less toxicity and non-relapse mortality compared to ATG-based prophylaxis. Further analysis including larger series and follow-up are needed to confirm these observations.

Disclosures
No relevant conflicts of interest to declare.
Hematopoeitic Stem Cell Transplant in Aplastic Anemia: Is It Time to Revise the Treatment Alogirthm
Authors: Gupta Ashish O. , Shein Steven L , Dalal Jignesh D 
Published: October 2019

Abstract
Background: Aplastic anemia (AA) is a rare bone marrow failure (BMF) syndrome of unknown etiology characterized by hypocellular bone marrow and severe persistent pancytopenia. Pediatric AA is more common in adolescent age group with better outcomes as compared to adults. Current treatment modalities include immunosuppressive therapy (IST) or matched related bone marrow transplant, when possible. There is a high risk of disease relapse with IST and clonal evolution into myelodysplastic syndrome. There is limited pediatric data on outcomes with different treatment options.
Methods: Retrospective database analysis of Pediatric Health Information Systems (PHIS) database was performed to evaluate healthcare outcomes of pediatric patients (age less than 21 years) with AA from January 1, 2006 to December 31, 2015. PHIS is an administrative quality-controlled database from 43 not-for-profit children's hospitals. ICD-9 code 284.9 was used to identify patients with acquired AA. Appropriate procedure and pharmacy billing codes were used to obtain information regarding transplants and various drugs used. SAS based statistical software was used to perform analysis.
Results: A total of 5127 inpatient admissions were noted for AA during the study period. An overall increasing trend of transplant was observed from 2006-2015 (Figure 1). Almost equal inpatient admission rate was noted in males and females, with a slightly higher rate amongst males who underwent transplant (55% vs 45%). Inpatient admission was more common amongst whites in both transplant (n=407, 8%) and non-transplant groups (n=4717, 92%; Table 1). Overall inpatient mortality was about 2% with a similar mortality in those who underwent transplant (5%). Cyclosporine (n= 1785, 38%) and steroids were most common immunosuppressive drugs used in non-transplant group. In the transplant group (Table 2), graft failure (20%) was the most common complication, while Cyclophosphamide (77%), Fludarabine (53%) and anti-thymocyte globulin (31%) based conditioning was most commonly used. Transplant itself was an independent risk factor for mortality (p=0.04) along with graft failure (p=0.02). Steroids (92%) and Cyclosporine (73%) were the most common immunosuppression used.
Conclusion: Hematopoietic stem cell transplants have good outcomes in pediatric AA patients. With an increasing trend of HSCT in these patients, successful outcomes with other transplant options such as match unrelated donor transplants should be considered. Treatment algorithm for Pediatric AA needs to be revised to include other transplant sources.

Disclosures
No relevant conflicts of interest to declare.
FVIII-Specific TCR Engineered Human Regulatory T Cells Suppress the Production of FVIII-Specific Responses Vitro and In Vivo
Authors: Kim Yong Chan , Zhang Aihong , Yoon Jeong-Heon , Scott David W. 
Published: October 2019

Abstract
Expanded antigen-specific engineered regulatory T cells (Tregs) have been proposed for potential clinical application for the treatment of undesirable immune responses, such as inhibitor responses in hemophilia A patients and autoimmune diseases. By providing an antigen-specific T-cell receptor (TCR) to polyclonal natural Tregs, we suggested that antigen-specific engineered Tregs would migrate specifically to particular target tissues and induce antigen-specific immune tolerance in the local milieu. Previously, we developed FVIII C2-specific Tregs using a long-term stabilization protocol in vitro and demonstrated that these stabilized engineered Tregs successfully modulated FVIII-specific T-cell and B-cell immune responses in vitro. Furthermore, these engineered Tregs could suppress T-effectors specific for additional epitopes in local milieu in both a cell contact and contactless manner. From these data, we hypothesized that IL-2 and related signaling pathways are major regulatory mechanisms of the suppression. To further investigate how IL-2R signaling is engaged to control T effectors and Tregs, we followed the phospho-STAT5 status of these cells kinetically. Our results showed clearly that IL-2 from activated T effectors is a key requirement for Treg activation, inducing subsequent blockage of STAT5 signal in T effectors by activated Tregs.
As further evidence of the efficacy of these specific Tregs, we then determined whether FVIII C2-specific Tregs could suppress the induction of FVIII inhibitor antibody in vivo. Thus, we transferred FVIII C2-specific human Tregs into HLA DR1 hemophilic mice and challenged them with FVIII in vivo. Our results showed that induction of FVIII-specific antibodies was inhibited for over 8 weeks. Taken together, our results suggest a potential therapeutic trial of FVIII-specific engineered Tregs in hemophilia A.

Disclosures
Kim: Henry Jackson Foundation: Patents & Royalties: Provisional submitted.