bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum Sickness and Plasma Cytokine Profiles After Treatment with Antithymocyte Globulin In Severe Aplastic Anemia Patients.
Authors: Feng Xingmin , Scheinberg Phillip , Nunez Olga , Biancotto Angelique , Takaku Tomoiku , McCoy J. Philip , Young Neal S. 
Published: October 2019

Abstract
Abstract 1162
Antithymocyte globulin (ATG) is the standard therapy for severe aplastic anemia (SAA). Currently, two different preparations are commercially available, produced in horse and rabbit. As foreign proteins, ATGs elicit immune response in humans. Foreign antigen and responding antibody form circulating immune complexes that may deposit in tissues and cause serum sickness (SS), usually around day 10 after initiation of ATG therapy. The relationship of human anti-ATG antibodies with SS and the cytokine profiles of ATG-treated patients are not defined. We studied human anti-ATG antibody titers and 27 cytokines in the plasma of 27 patients who received horse ATG (hATG) and 25 patients who received rabbit ATG (rATG) for SAA. Cyclosporine was administered with both ATGs to achieve trough levels of 200–400 ng/mL. Plasma samples were obtained at: baseline pre-treatment, weekly in the first month, and at 3 and 6 months after ATG treatment. Nine of 25 (36%) rATG recipients and 5 of 27 (19%) hATG recipients developed SS at about week two. When measured by enzyme-linked immunosorbent assay, human anti-hATG or rATG antibody titers peaked during weeks 2–3, and then declined at month 2, reducing to baseline levels at month 6. All 9 rATG-treated patients who developed SS had significantly higher antibody titers at week 2 than did 16 rATG-treated patients without SS (O.D. 1.704 ± 0.173 vs 0.664 ± 0.076, p < 0.0001), a difference also presented at month 3 (p = 0.002). In hATG-treated patients, human anti-hATG antibody titers did not appear to correlate with the occurrence of SS. We measured cytokines using a 27-plex cytokine magnetic bead-based Luminex assay. Both hATG and rATG-treated patients without SS showed similar cytokine profiles: a peak in MIP-1β, IL-8, IL-10, IL-13, G-CSF and IP-10 at day 2, which rapidly declined to baseline; this early-phase response may be the direct effect of ATG infusion. In rATG-treated patients, SS patients had significantly higher plasma levels of IFNγ, IL-1ra, IL-12 (p < 0.0001), IL-4, IL-1β (p = 0.0001), IL-6 (p = 0.0002), IL-10 (p = 0.0003), IL-17, GM-CSF, FGFb (p = 0.0015), IL-15, MIP-1α (p = 0.0046), PDGF (p = 0.0052), IL-13 (p = 0.0066), and IL-2 (p = 0.0077) than did non-SS patients at weeks 2 and 3; this late-phase response may be secondary to heterologous antibodies to rATG. In conclusion, human anti-ATG antibodies were frequently detected after ATG administration; antibody titers associated with SS in rATG-treated patients; and SS patients and non-SS patients showed broadly distinct cytokine profiles.

Disclosures:
No relevant conflicts of interest to declare.
p53 Dependent and Dose Dependent Effects of Rps29 Mutation In the Zebrafish Embryo.
Authors: Taylor Alison M. , Humphries Jessica M. , White Richard M. , Murphey Ryan D. , Burns Caroline E. , Zon Leonard I. 
Published: October 2019

Abstract
Abstract 1170
Diamond Blackfan anemia (DBA) is a rare congenital disease characterized by red cell aplasia and craniofacial abnormalities. Ribosomal protein genes are often mutated in patients with this disease, but the mechanism of action is still being investigated. To elucidate the effect of mutations in ribosomal proteins, we are studying a zebrafish rps29 mutant with hematopoietic and endothelial defects. Hematopoietic stem cells (HSCs) in rps29-/- embryos are significantly decreased, as assayed by runx1 and cmyb expression. Although the aorta and posterior cardinal vein form in the mutant, intersomitic vessel formation is affected. To test whether decreased p53 levels can rescue these defects, we crossed fish with mutated p53 into the rps29 background. In rps29-/-;p53-/- embryos, the vascular and HSC phenotypes are rescued, demonstrating that p53 may be required for these effects of rps29 knockdown. We performed a microarray comparing rps29-/- embryos and their siblings to identify genes that are differentially expressed in the mutant. Using gene set enrichment analysis (GSEA), we determined that the list of genes up-regulated in the rps29 mutant is enriched for genes up-regulated by p53 in response to irradiation. Many of the genes identified have known roles in apoptosis and stress response. We have also identified genes whose expression correlates with the number of wildtype copies of rps29. Orthopedia homolog a (otpa), which is specifically expressed in forebrain and hindbrain tissues at 24 hours post fertilization (hpf), is decreased in heterozygous siblings and further decreased in homozygous siblings. In addition, p53 knockdown partially increases otpa levels in the mutant. These data support a model where p53 activation is one of the critical downstream mediators of rps29 knockdown in several tissues, but the mechanism of tissue specificity remains unclear. The otpa phenotype suggests that regulation of some genes is dependent on rps29 levels. The zebrafish rps29 mutant will be a useful model for understanding how a decrease in ribosomal protein levels can cause specific defects in hematopoietic and neural tissues.

Disclosures:
Zon: FATE, Inc.: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Stemgent: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.
Analysis of Cell Aggregation In Thawed Hematopoietic Stem Cell Products Using Micro-Flow Imaging.
Authors: Wu Luke , Martin Teresa , Halpenny Michael , Giulivi Antonio , Allan David S. 
Published: October 2019

Abstract
Abstract 1187

Background:
Cell aggregation can be observed after thawing cryopreserved hematopoietic stem cell products used in transplantation. Micro-flow imaging (MFI) is a novel method of imaging biologic fluids and provides a means of quantifying cell aggregation.

Method:
Umbilical cord blood (UCB) was collected following informed consent and cryopreserved in 5% DMSO and 37% (w/v) pentastarch in liquid nitrogen. Aliquots of cryopreserved peripheral blood progenitor cell (PBPC) products were cryopreserved under similar conditions. Cells were thawed rapidly and filtered before analysis using MFI.

Result:
Large cellular aggregates were identified in all thawed PBPC samples analyzed (n=4) with a mean reduction in total cells of 19.7 ± 9.8% at 1 hour and 49.8 ± 15.9% at 24 hours. Cellular aggregates ≤ 170 um were visualized, sized and digitally imaged with MFI. Analysis of larger clumps was limited due to size of the analysis chamber. Cell transparency and circularity were unchanged over 24h after thawing and similar to freshly isolated PBPCs. Mononuclear cell yields did not diminish over 24 hours in freshly isolated PBPC (n=3, p>0.05) or in fresh UCB (n=3, p>0.05). Thawed UCB samples did not demonstrate significant clumping and maintained higher yields of total cells compared with PBPCs (p=0.02). Filtering of thawed PBPC products using standard blood transfusion filters (Baxter, 170 um) did not change the qualitative nature of observed cellular aggregates. The loss of cells in PBPC products correlated with early apoptotic mononuclear cells (7AAD-AnnV+). Treatment with DNase I eliminated the presence of observable cell clumping in thawed PBPCs at 24h with a marked improvement in cell yield at 24h (p<0.0001).

Conclusion:
Micro-flow imaging provides novel insight regarding cellular aggregation of blood stem cell products. Significant cell clumping occurs in cryopreserved PBPC after thawing and aggregates are not removed by standard transfusion filters. Aggregation increases with time after thawing and may influence the final dose of cells available for engraftment after transplantation. Fresh PBPC collections contain few aggregates and both fresh and thawed cryopreserved UCB demonstrated minimal cell clumping. Apoptosis induced by cryopreservation and thawing may contribute to increased aggregation in PBPCs and DNase I appears to preserve higher yields of total cells. New cryoprotectants that limit apoptosis are needed and methods to reduce cell clumping appear warranted.

Disclosures:
Martin: Brightwell Technologies: Employment.
Involvement of a B1 Progenitor In a Murine Model of BCR-FGFR1 Induced Leukemogenesis.
Authors: Tidwell Josephine A , Ren Mingqiang , Cowell John K 
Published: October 2019

Abstract
Abstract 1221
Constitutive activation of the FGFR1 kinase domain through rearrangement with dimerization domains from various proteins leads to an atypical myeloproliferative disease (MPD). Although the majority of these rearrangements result in development of T-cell leukemia/lymphoma, in the case of the BCR-FGFR1 rearrangement the phenotype is predominantly a myeloid and B cell MPD. To investigate the etiology of this disease, a murine model of BCR-FGFR1 was created using a bone marrow transduction/transplantation approach. Consistent with the human disease, recipient mice developed clear myeloproliferations marked by CML-like basophilia as well as extramedullary leukemic transformation containing myelo- or lymphoblasts, with neoplasms of myeloid and B cell lineages. Flow analysis demonstrated a CD43+ phenotype in leukemic B cells suggesting a block in the differentiation of pro-B progenitor cells. A cell line (BBC1) has now been established with this immature B cell immunophenotype albeit B220-, consistent with a recently described B1 progenitor. These cells can differentiate in vitro with characteristics of both macrophage and dendritic lineages. When BBC1 cells are injected into normal mice, leukemogenesis marked by a hypercellular bone marrow and splenomegaly is induced. Although BBC cells show the same progenitor B cell immunophenotype seen in the parent cells throughout the hematopoietic system, tumor cells in the peritoneum lose CD43 expression, down-regulate CD19 expression and upregulate CD11b and F4/80 demonstrating a capacity to differentiate in this environment. In this model, therefore, the etiology of BCR-FGFR1 disease closely mimics that seen in humans and we have identified a likely B cell subtype involved in leukemic transformation.

Disclosures:
No relevant conflicts of interest to declare.
Risk Score at Diagnosis and the Dynamics of Response to TKI Therapy In Chronic Myeloid Leukemia.
Authors: Lenearts Tom , Castagnetti Fausto , Traulsen Arne , Pacheco Jorge M , Rosti Gianantonio , Dingli David 
Published: October 2019

Abstract
Abstract 1236

Background:
Although most patients with early chronic phase CML (ECP-CML) respond to TKI therapy, the depth and speed of response can be different. While it is known that both the Sokal and Hasford scores have an impact on the speed and depth of response, no mechanisms explaining these differences have been identified.

Objective:
To provide explanations for any potential differences in CML response as a function of the Sokal and Hasford score using a computational model.

Methods:
We utilize a computational model of hematopoiesis and CML, together with serial quantitative data of disease burden under nilotinib therapy to determine the fraction of CML cells responding to therapy (z) and the impact of TKI on the self-renewal probability of CML cells (e) under therapy. Patients were stratified at diagnosis on both the Sokal and Hasford scoring system. A non-linear least squares method was used to separately fit the model to serial Q-RT-PCR data for BCR-ABL in response to therapy in each cohort.

Results:
A total of 73 patients were studied. The number of patients with low, intermediate and high risk disease based on the Sokal score was 34, 29 and 10 respectively while the respective distribution of patients on the Hasford score was 29, 43 and 1. Although the impact of nilotinib on the self-renewal probability of CML progenitor cells was similar across all risk groups (there were substantial differences in the fraction of cells responding to therapy: For the Sokal groups, the fraction of cells (z) responding to therapy decreased from 0.09 to 0.086 and 0.069 respectively for low, intermediate and high risk disease. In the case of the Hasford score, the difference in z between low and intermediate categories becomes more pronounced, i.e. z is 0.093 for low and 0.08 for intermediate risk disease.

Conclusions:
The risk score at diagnosis of CML has a direct impact on the dynamics of response to TKI therapy. Patients with a lower risk score respond faster to the same therapy when compared to high risk patients. The impact of TKI on the self renewal of CML cells appears to be the same regardless of the risk score but the fraction of cells responding decreases as the risk score increases. This suggests that subclones that may be less sensitive to TKI therapy may be emerging. Strategies that increase the fraction of cells responding to therapy in patients with higher risk disease may be indicated.

Disclosures:
Rosti: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau; Roche: Speakers Bureau.
5-Azacytidine and G-CSF Derepressed Chromatin Structure of PU.1 and Its Targets Cebpa and Cbfb In Myelodysplastic Syndrome (MDS)
Authors: Stopka Tomas , Burda Pavel , Basova Petra , Vargova Karin , Curik Nikola , Jonasova Anna , Trneny Marek 
Published: October 2019

Abstract
Abstract 124
The myelodysplastic syndrome (MDS) represents a heterogeneous disorder characterized by ineffective hematopoiesis and evolution to acute myelogenous leukemia that is strikingly refractory to current therapeutic approaches. Novel epigenetic drugs including DNA-methyltransferase inhibitor 5-Azacitidine (5-AZA, Vidaza) are currently considered to improve clinical response in patients with MDS. MDS is characterized by abnormal differentiation and blocked maturation responsive to 5-AZA, therefore we studied major regulator of hematopoietic differentiation, transcription factor PU.1 as a candidate target of the epigenetic therapy. Transcription factor PU.1 represents very important myelo-lymphoid regulator of differentiation. PU.1 expression is regulated by Upstream Regulatory Element (URE) and its deletion in mouse caused downregulation of PU.1 leading to acute leukemia (Rosenbauer 2004). Our laboratory recently demonstrated that PU.1 in murine acute leukemic cells binds and promotes derepression of CCAAT/enhancer binding protein (C/EBP) alpha (Cebpa) and Core-binding factor, beta subunit (Cbfb) (Burda 2009) that encode two key hematopoietic transcription factors involved in myeloid differentiation. Furthermore, transcriptional regulation through PU.1 binding sites of Cebpa and Cbfb loci involves quantitative increases in a transcriptionally active chromatin mark: acetylation of histone H3 lysine K9. Others reported that Cebpa expression is augmented by G-CSF (Dahl 2003). To determine if 5-AZA regulates PU.1 and its targets we determined their expression and chromatin structure following the 5-AZA treatment in MDS patient-derived blasts and in cell lines derived from MDS (MOLM-13, OCI-M2, SKM-1) and AML (K562). Our data provide evidence that in the chosen cell lines and in so far limited number of patients-derived cells (N=4) the gene expression of PU.1 and its direct targets Cebpa and Cbfb is stimulated by 5-AZA and this effect is further enhanced by G-CSF. Furthermore, marks of activated chromatin structure including histone H3K9 hyperacetylation and H3K4 hypermethylation are increased at the URE of the PU.1 gene again documenting its transcriptional activation. Conversely, levels of H3K9 methylation at URE are significantly reduced upon 5-AZA treatment documenting 5-AZA stimulates loss of repressive chromatin structure near PU.1 gene. These observations are currently compared with responsiveness of the patients to 5-AZA in vivo and expanded to larger set of patients. Our data collectively supports importance of the chromatin structure upstream of PU.1 gene and of its direct targets Cebpa and Cbfb in patients with MDS that may add to better understanding of effectiveness of epigenetic therapy in MDS. (Grants # IGA 10310-3, MSMT 2B06077, SVV-2010-254260507, MPO FR-TI2/509, GAUK 251135 82210).

Disclosures:
No relevant conflicts of interest to declare.
Zygomycosis After Allogeneic Hematopoietic Stem Cell Transplantation: A French Multicenter Cohort Study (2003-2008)
Authors: Xhaard Alienor , Fanternier Fanny , Dannaoui Eric , Bergeron-Lafaurie Anne , Lacroix Claire , Herbrecht Raoul , Legrand Faezeh , Mohty Mohamad , Michallet Mauricette , Cordonnier-Carlet Catherine , Malak Sandra , Guyotat Denis , Couderc Louis Jean , Socie Gerard , Lortholary Olivier , Ribaud Patricia 
Published: October 2019

Abstract
Abstract 1263

Background:
To evaluate the clinical characteristics and outcome of zygomycosis (ZG) in allogeneic hematopoietic stem cell transplant (HSCT) recipients.

Methods:
Retrospective cohort study involving HSCT patients with ZG diagnosed between 2003 and 2008, from 19 centres. During this period, 4138 allogeneic HSCT were performed in these centers.

Results:
ZG incidence was 0.56% (n=23). Twenty patients (87%) were male. Median age was 44 years (range: 3 to 63 years). Donors were non HLA-identical in 14 cases and conditioning regimens were reduced intensity in 8. ZG occurred a median of 217 days post transplant (range: 0 to 2693 days). Fifteen patients had active graft-versus-host disease (GVHD). Twenty patients were receiving steroids at a median dose of 1 mg/kg/day (range: 0.1 to 2 mg/kg/day) at ZG diagnosis. Ten patients (43%) had diabetes mellitus. Nine patients (39%) had experienced a previous proven or probable invasive filamentous fungal infection (Aspergillus: 8, Trichoderma:1) a median of 115 days (range: 8 to 392 days) before ZG diagnosis. ZG was a breakthrough infection in 20 cases. Before ZG diagnosis, 13 patients were on voriconazole therapy for a median duration of 61 days (range 3 to 394 days), 4 patients were on posaconazole (PCZ) for a median of 61 days (range 7 to 88 days). Other patients were receiving caspofungin, itraconazole or voriconazole. Lungs were the most common site of infection (65%); two patients had a disseminated infection. Histology was performed in 52% of the patients, and contributed to diagnosis for 83% of biopsies. Culture was positive in 83% of cases. The main causal species were Lichtheimia spp. and Rhizopus spp. Median time between the first clinical symptom and diagnosis was 8 days (range: 2 to 34 days). Twenty patients received an antifungal. All but 2 patients received a lipid formulation of amphotericin B as first-line treatment. Eleven patients received PCZ, two as first-line treatment. Surgery was performed in eight patients. Median treatment duration was 47 days (range: 2 to 730 days). Nine patients responded to treatment. Nineteen patients (83%) died a median of 46 days after ZG diagnosis (range: 0 to 1449 days). ZG attributable mortality was 79% (15/19 patients). Four patients are alive a median of 706 days after ZG diagnosis (range: 705 to 1955 days).

Conclusion:
ZG is a late event with a poor prognosis after allogeneic HSCT. Because ZG diagnosis is difficult, special attention must be paid to patients on long-term antifungal treatment for a previous mold infection, and with protracted GVHD.

Disclosures:
No relevant conflicts of interest to declare.
Pre-Engraftment Syndrome Following Umbilical Cord Blood Transplantation Is a Strong Predictor of Acute Graft-Versus-Host Disease
Authors: Wang Xingbing , Sun Zimin , Liu Huilan , Geng Liangquan , Ding Kaiyang , Zhu Weibo , Wang Zuyi 
Published: October 2019

Abstract
Abstract 1267
Pre-engraftment syndrome (PES) has been described in patients receiving umbilical cord blood transplantation (CBT). However, PES remains poorly characterized, and the prognosis and appropriate management are unclear. Therefore, we retrospectively analyzed the incidence, risk factors, manifestations, and clinical outcome of PES in CBT recipients treated for hematological malignancies at our transplantation center.
A total of 60 patients (median 20 years, range 3–48) received either myeloablative (n=52) or reduced-intensity (n=8) conditioning. 28 patients received double unit grafts to augment engraftment. Cyclosporine-A and mycophenolate mofetil were used as GVHD prophylaxis, and all patients received post-transplant granulocyte colony-stimulating factor.
In this study, PES was defined as noninfectious fever (>38.3°C) and/or unexplained rash occurring before neutrophil engraftment. 38 patients (63.3%) fulfilled PES criteria: 33 with fever and 36 with rash. The median onset was 8 days (range 3–15) post-transplant (a median of 12 days before neutrophil recovery). 34 patients received IV methylprednisolone (MP) (0.5-2 mg/kg/d) with 27/34 (79.4%) having fever and/or rash resolution in <48 hours. Univariate analysis identified myeloablative conditioning and younger age as significant risk factors for developing PES. Use of TBI or ATG in conditioning regimen, the infused total nucleated cell dose, gender, weight, blood type mismatch, transplantation of UCB units and degree of donor-recipient HLA disparity were not significantly associated with the development of PES in our series. The cumulative incidence of sustained donor engraftment was 83.3%. Patients with PES had a higher incidence of developing grade II -IV acute GVHD, but PES was not associated with sustained donor engraftment, the day to neutrophil recovery and chronic GVHD. Overall survival did not significantly differ between patients with and without PES.
We conclude that PES is common following CB transplant (CBT), predicts for aGVHD, and responds promptly to corticosteroids.

Disclosures:
Wang: Fund of the Key Medical Project of Anhui Provincial healthy department (2010A005): Research Funding; Clinical Technology foundation of Anhui Provincial healthy department (2008A011): Research Funding; Fund of Anhui Provincial “115” Industrial Innovation Program: Research Funding; Anhui Provincial Outstanding Young Investigator Program (08040106810): Research Funding.