bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Inverse Correlation of Regulatory T Cells and Time to Initial Treatment in Chronic Lymphocytic B-Cell Leukemia.
Authors: Weiss Lukas , Melchardt Thomas , Grabmer Christoph , Egle Alexander , Tinhofer Inge , Greil Richard 
Published: October 2019

Abstract
Abstract 1238
Poster Board I-260
Regulatory T cells (Treg) are thought to be potent suppressors of anti-tumor immunity and increased Treg frequencies are correlated with poor prognosis in patients suffering from various tumor types. In the current study we analysed Treg (CD3+CD4+CD25+CD127−) in the peripheral blood of 101 previously untreated chronic lymphocytic B-cell leukemia (B-CLL) patients as well as 170 healthy volunteers using flow cytometry. Statistical analysis was used for correlation with clinical data. Treg of B-CLL patients expressed high numbers of FOXP3 and efficiently suppressed T cell proliferation. No significant difference in relative Treg numbers between B-CLL patients and healthy controls could be observed, but Treg numbers showed a significant negative correlation with time to initial treatment. Defining a cut-off of 9.75%, patients with higher Treg showed significantly shorter time to initial treatment (median 4.4 yr, 95% CI 2.2 – 6.6 yr) when compared to the lower Treg group (median not reached at 4.25 yr) (logrank P=0.001). Further subdivision of patients into quartiles according to Treg numbers showed a clear dose-dependency (logrank P=0.027). Treg numbers had significant prognostic power for time to initial treatment in univariate (P=0.001) as well as multivariate (P=0.037) Cox-regression analysis including Rai stage, IgVH mutational status, chromosomal aberrations and CD38 expression. In conclusion, higher Treg numbers are significantly and independently correlated with shorter time to initial treatment in B-CLL in a dose-dependent fashion and show significant prognostic power for time to initial treatment. These results provide evidence for the role of Treg in the clinical course of B-CLL.

Disclosures
No relevant conflicts of interest to declare.
Increased Interferon-αa Signaling During Megakaryocyte Ontogeny: Implications for the Spontaneous Resolution of Down Syndrome Transient Myeloproliferative Disorder.
Authors: Wieland Karen , Woo Andrew , Akie Thomas , Cantor Alan B. 
Published: October 2019

Abstract
Abstract 1272
Poster Board I-294
About ten percent of infants with Down syndrome (DS) are born with a transient myeloproliferative disorder (DS-TMD), which spontaneously resolves within the first few months of life. However, the basis for this resolution remains unknown. Acquired mutations leading to exclusive production of a short isoform of the transcription factor GATA-1 (GATA-1s) occur in all cases of DS-TMD, and knock-in mice that exclusively produce GATA-1s have hyperproliferation of megakaryocytes during early fetal liver hematopoiesis, but not during later developmental stages. In this study, we found striking upregulation of the interferon-αa (IFN-αa) receptor and multiple IFN-αa responsive genes, including Ifi203, Ifi205, Irf-1, Irf-8, and Ifitm6, in immunophenotypically isolated megakaryocyte progenitor cells (MkPs) from bone marrow versus embryonic day 13.5 (e13.5) fetal liver of wild type mice. These differences were confirmed at the protein level in megakaryocytes by in situ immunohistochemistry. Addition of IFN-αa to GATA-1s containing e13.5 fetal liver MkPs reduces their hyperproliferation in vitro in a dose-dependent manner. Conversely, injection of neutralizing IFN-αa/β antibodies, but not control IgG, into adult GATA-1s mice markedly increases the percentage of bone marrow CD41+ cells and morphologically recognizable megakaryocytes, in contrast to wild type mice. We propose that increases in IFN-αa signaling during megakaryocyte ontogeny may account for the developmental stage-specific effects of GATA-1s on megakaryocyte hyperproliferation, and possibly the spontaneous resolution of DS-TMD. Interestingly, the genes encoding the IFN-αa/β receptor are located on human chromosome 21 and are expressed at 1.6 times that in trisomy versus disomy 21 cells. We speculate that increased interferon alpha signaling during embryogenesis may be the basis for the strong selective pressure for GATA-1s producing mutations in trisomy 21 fetuses in the first place.

Disclosures
No relevant conflicts of interest to declare.
The PAF Complex Synergizes with MLL Fusion Proteins at .Hox Loci to Promote Leukemogenesis.
Authors: Muntean Andrew G. , Tan Jiaying , Basrur Venkatesha , Elenitoba-Johnson Kojo S.J. , Hess Jay 
Published: October 2019

Abstract
Abstract 1277
Poster Board I-299
Mixed lineage leukemia (MLL) is a histone H3 lysine 4 methyltransferase that is required to maintain a normal hematopoietic stem cell compartment. MLL functions to maintain expression of HOX genes as well as the HOX co-factor MEIS1, which play significant roles in regulating hematopoiesis. MLL is involved in chromosomal translocations with up to sixty different partners in both acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). HOXA9 and MEIS1, are directly regulated by MLL fusion proteins and are crucial for MLL fusion protein mediated transformation. The deregulated expression of target genes in AML is dependent on specific protein-protein interactions and functional domains of MLL. For example, the tumor suppressor Menin bridges LEDGF to the extreme N-terminus of MLL and both of these interactions are necessary for transformation. Furthermore, a DNA methyltransferase homology region (CxxC domain) of MLL is essential for binding to non-methylated CpG islands and MLL-fusion protein oncogenesis. We have found that sequences downstream of the CxxC domain, termed the RD2 region, that interact with the Polymerase Associated Factor (PAF) complex are also required for MLL fusion protein mediated transformation. The PAF complex interacts with RNA polymerase II and is required for H2B mono-ubiquitination and subsequent histone H3K4 and H3K79 methylation. Together the PAF complex has been shown to be involved in transcriptional initiation, elongation and termination. Interaction of MLL with the PAF complex is mediated through direct contacts with two subunits: Ctr9 and PAF1. The PAF complex synergizes with MLL-AF9 to augment transcriptional activation of the Hoxa9 promoter. Furthermore, MLL fusion proteins recruit high levels of the PAF complex to the Hoxa9 promoter. Importantly, deletions of the MLL RD2 region that abolish interactions with the PAF complex eliminate MLL-AF9 mediated transformation of mouse bone marrow cells. Transcription of PAF components is dramatically downregulated during differentiation of hematopoietic cells, consistent with recent data showing a requirement for the PAF complex to maintain an embryonic stem cell phenotype. Knock down and transplantation experiments are underway to further define how the PAF complex regulates normal MLL function and cooperates with MLL fusion proteins to promote leukemogenesis.

Disclosures
No relevant conflicts of interest to declare.
Formation of FVIIa-Antithrombin Complexes After Administration of rFVIIa to Hemophilia Patients.
Authors: Ezban Mirella , Martin Erika , Barrett John Christian , Kuhn Janice , Nolte Mindy , Pelzer Hermann , Agerso Henrik , Petersen Lars Christian , Hedner Ulla , Carr Marcus E. , Brophy Donald 
Published: October 2019

Abstract
Abstract 1295
Poster Board I-317

Introduction
Recent animal studies suggest that measurable amounts of factor VIIa and antithrombin (AT) complexes are formed and accumulate following rFVIIa administration. The in vivo rate of inhibition has been reported to be faster than the un-stimulated in vitro reaction between AT and free rFVIIa and of the same order of magnitude as the rate determined in the presence of tissue factor. To study the impact of AT inhibition on the elimination of rFVIIa in humans, we measured the pharmacokinetics (PK) of rFVIIa and rFVIIa-AT complex formation in 10 hemophilia A or B patients.

Patients and Methods
The PK of single-dose rFVIIa 90 μg/kg (Novo Nordisk A/S) was evaluated in 10 severe FVIII- or FIX-deficient patients in a non-bleeding state. The plasma concentrations of FVIIa activity (FVII:C), FVII antigen (FVII:Ag), FVIIa-AT, D-dimer and F1+2 fragment were determined immediately before, and at 0.5, 1, 2, 4 and 6 hours following rFVIIa dosing.

Results
Significant amounts of FVIIa–AT complex were formed in vivo after rFVIIa administration, and reached a maximum of 5.4 ± 0.8 nmol/L [mean ±SD] at 2 hours following rFVIIa administration and declined to 4.4 ± 0.9 nmol/L at 6 hours, as compared to 0.1 ± 0.05 nmol/L at baseline. While the FVII:C PK data in this study were consistent with previous data, there was greater total body clearance (Cltot), a larger volume of distribution (Vdss) and a shorter plasma half-life (T1/2) of FVII:C relative to FVII:Ag (Table). No change in D-dimer was observed after the administration of rFVIIa, while a slight increase in F1+2 fragment levels to 258 ± 73 pmol/L was measured 4 hours after rFVIIa dosing, as compared to 141 ± 45 pmol/L at baseline.

Conclusion
A significant divergence between the clearance of rFVIIa, as determined by either FVII:C or FVII:Ag measurements, can be accounted for by AT complex formation. Inhibition by AT appears thus to have a significant impact on the elimination of FVII:C activity from the circulation when rFVIIa is administered at a therapeutic dose. Similar to animal data, the formation of the FVIIa-AT complexes in vivo was faster than anticipated from in vitro studies, indicating that the exposure to the vessel wall stimulates the FVIIa inhibition by AT. Analyses of coagulation parameters did not indicate induction of systemic coagulation.

Disclosures
Ezban: NovoNordisk A/S: Employment. Pelzer:NovoNordisk: Employment. Agerso:NovoNordisk: Employment. Petersen:NovoNordisk: Employment. Hedner:NovoNordisk: Employment. Carr:NovoNordisk: Employment.
Quantitation of Changes in VWF and FVIII Following Elective Orthopedic Surgery in Normal Individuals.
Authors: Kahlon Amrit , Grabell Julie , Tuttle Angie , Engen Dale , Hopman Wilma , Lillicrap David , James Paula 
Published: October 2019

Abstract
Abstract 1296
Poster Board I-318

Background
Patients with inherited bleeding disorders undergoing surgery typically receive therapy to correct the deficient factor to a level of ∼1.0 IU/mL. There is a paucity of well-constructed descriptive data quantifying the changes in coagulation that occur in response to surgical stress in normal individuals, however. Additionally, von Willebrand factor (VWF) and factor VIII (FVIII) are acute phase reactants, and thus, supratherapeutic levels of these proteins that might develop in response to the surgical stress would predispose patients to thrombotic events. Aim: With this in mind, our objective was to quantify the changes in hemostatic variables that occur in response to elective orthopedic surgery in normal individuals.

Methods
Eligible subjects > 18 years of age undergoing total knee or total hip replacement were recruited. Exclusion criteria included a known bleeding disorder, hormone replacement therapy, use of oral contraceptives or pregnancy. Following informed consent, blood samples were drawn at five time points: 1) baseline - in clinic 1-2 weeks pre-operatively (pre-op), 2) pre-op the morning of surgery – same day admitting center, 3) intra-operatively (intra-op) – 30 minutes after the start of surgery, 4) 30 minutes post-operatively (post-op) - recovery room, and 5) post-op day one (POD 1) – on the ward. Samples were analyzed for complete blood counts (CBC), prothrombin time (PT), activated partial thromboplastin time (aPTT), VWF antigen (VWF:Ag), VWF ristocetin cofactor activity (VWF:RCo), FVIII coagulant activity (FVIII:C) and whole blood thromboelastography (TEG) without tissue factor activation. Repeated measures analysis of variance was used to evaluate trends over time; paired samples t-tests were done to maximize the sample size for pairwise comparisons.

Results
37 subjects were recruited (25 females, 12 males) with a mean age of 64 years (range 33 – 87). Means and ranges for all laboratory parameters are displayed in Table 1 in addition to statistical analysis of the change in all variables over the 5 time points. Statistically significant changes were seen in all variables except PTT and TEG angle. In general, VWF and FVIII indices decreased during surgery (presumably due to consumption) and then increased in the post-operative period (presumably due to a stress response). A great deal of variability was seen in post-operative levels of VWF and FVIII between individuals with some showing borderline low levels and some achieving very high levels.

Conclusion
These data establish a baseline on which to reconsider current strategies for the peri-operative management of patients with inherited bleeding disorders, and provide relevant information when considering the relative risks of bleeding or thrombosis associated with surgery.

Disclosures
No relevant conflicts of interest to declare.
Rapamycin and IL-2 Prevents Lethal Acute Graft-Versus Host Disease by Expansion of Donor Type CD4+CD25+Foxp3+ Regulatory T Cells.
Authors: Shin Ho-Jin , Baker Jeanette , Leveson-Gower Dennis , Sega Emanuela I , Negrin Robert 
Published: October 2019

Abstract
Abstract 1334
Poster Board I-356
Previous work has demonstrated that both rapamycin (RAPA) and IL-2 enhance CD4+CD25+Foxp3+ regulatory T cells (Treg) proliferation and function. We investigated whether the combination of RAPA and IL-2 administered in vivo could reduce acute graft-versus-host disease (aGVHD) induction and increase survival after bone marrow transplantation (BMT) by induction of Treg. T cell depleted bone marrow (TCD-BM) cells from wild type C57BL/6 mice were injected after lethal irradiation with (800 cGy) into Balb/c recipients on day 0. To induce aGVHD and evaluate the proliferation of donor T cells by in vivo bioluminescence imaging, 1 × 106 conventional CD4+ and CD8+ T cells (Tcon) from luciferase-expressing (luc+) transgenic C57BL/6 were injected intravenously on the same day. RAPA was administered intraperitoneally (dose of 0.5 mg/kg/day) for 14 days and IL-2 (dose of 5 × 104 IU) for 3 days (twice a day). RAPA plus IL-2 significantly reduced the expansion of luc+ Tcon more than RAPA (P=0.04) or IL-2 alone (P=0.002) or no treatment (P = 0.01). Weight loss and aGVHD score were significantly reduced in the mice which were injected with the combination of RAPA and IL-2 compared with those animals injected with RAPA (P = 0.03) or IL-2 alone (P = 0.05). The percentage of donor type CD4+CD25+ cells was increased and CD4+CD25− T cells were reduced from thymic and extrathymic tissues after treatment with RAPA plus IL-2 on day 7 after BMT. The combination of RAPA and IL-2 resulted in a 2.4 fold (mesenteric LN), 2.7 fold (peripheral LN), 4.2 fold (spleen) and 2.1 fold (thymus) increase in the percentage of donor type CD4+CD25+Foxp3+ Treg. In animals receiving the combination of RAPA and IL-2, the percentage of CD4+CD25+Foxp3+ T cells increased from 8.98% (RAPA alone) to 24.2% (RAPA plus IL-2) at 7 days after BMT, representing a 2.7 fold expansion. The cell numbers of CD4+ and CD8+ T cells and CD4+CD25− T cells were reduced and CD4+CD25+Foxp3+ Treg were expanded in the thymus and extrathymic tissues after administration RAPA and IL-2. To study the origin of the expanded Treg in RAPA plus IL-2, BALB/c recipient mice were injected with purified donor CD4+CD25highFoxP3+ Treg and CD4+CD25− and CD8+CD25− (both Foxp3−) Tcon after lethal irradiation followed by RAPA plus IL-2 for 7 days. The combination of RAPA and IL-2 increased the expansion of donor type CD4+CD25+Foxp3+ Treg, but did not result in an increase in the conversion of Foxp3+ Treg from donor CD25− Tcon. We also evaluated whether Foxp3+ non-Treg were present in the expansion of Treg by RAPA plus IL-2 by evaluating interferon-γ- and IL-2-production which was minimally detected in the Foxp3+ cells. In conclusion, the combination of RAPA and IL-2 after BMT synergistically promoted the expansion of donor CD4+CD25+Foxp3+ Treg resulting in prevention of lethal aGVHD.

Disclosures
No relevant conflicts of interest to declare.
In-Hospital Outcomes Among Sickle Cell Patients with Acute Chest Syndrome: Results From a National Database.
Authors: Kamble Shital , Reed Shelby D , Grussemeyer Chelsea , Telen Marilyn J. 
Published: October 2019

Abstract
Abstract 1367
Poster Board I-389

Objective:
Acute chest syndrome is the leading cause of death and the second most common cause of hospitalization in patients with sickle cell disease (SCD), yet there are no recent estimates of its associated impact on medical resource use and costs. In this study, we compared inpatient mortality, length of stay (LOS) and total costs among hospital discharges for SCD patients with acute chest syndrome (ACS), SCD patients with crisis, and SCD with neither ACS nor crisis (controls).

Methods:
Using the 2006 Nationwide Inpatient Sample (NIS) data of the Healthcare Cost and Utilization Project, we developed three groups of discharges with SCD (Clinical Classification Code 61): (1) ACS with or without crisis on the basis of ICD-9-CM codes 517.3 (ACS) or 486 (pneumonia), (2) sickle cell crisis without ACS, using ICD-9-CM codes 282.42, 282.62, 282.64 or 282.69; and (3) SCD patients without a diagnosis of ACS or sickle cell crisis. We excluded cases representing elective admissions, patients discharged to short-term hospitals, born in the hospital, and women giving birth. We used generalized linear regression models to compare LOS (negative binomial distribution, log link) and inpatient costs (gamma distribution, log link) between study groups while controlling for gender, age, payer, 29 comorbidities, and hospital characteristics, including rural vs. urban location, teaching status, bed size, ownership type, and hospital region. We did not perform adjusted comparisons for mortality due to small numbers.

Results:
We identified 2,971 discharges with ACS, 13,593 with sickle cell crisis, and 4,040 with neither condition coded. Median age was 25 for ACS, 27 for sickle cell crisis, and 29 for sickle cell ‘controls’. Females represented 50.8% of discharges with ACS, 56.1% of discharges with sickle cell crisis, and 55.8% of sickle cell controls. Inpatient mortality was low across all three groups (Table). After adjustment for patient and hospital characteristics, discharges with ACS incurred hospital stays that were 24% longer (95%CI: 1.20-1.28, P<.0001) than those with crisis and 68% longer (95%CI: 1.62-1.74, P>.0001) than SCD controls. Similarly, inpatient costs among ACS discharges were 45% higher (95%CI: 1.40-1.49) than discharges with sickle cell crisis and 62% higher (95%CI: 1.56-1.68,P<.0001) than for SCD controls. Discharges for patients with sickle cell crisis were 35% longer (95%CI: 1.31-1.39, P<.0001) and 12% more costly (95%CI: 1.09-1.15, P<.0001) than for sickle cell controls.

Conclusion:
SCD patients admitted to the hospital with ACS incur significantly higher costs and longer stays than SCD patients with crisis or neither of these conditions.

Disclosures:
No relevant conflicts of interest to declare.
Cost-Effectiveness of Ferric Carboxymaltose Supplementation in Chemotherapy-Induced Anemia Patients Treated with Erythropoiesis-Stimulating Agents.
Authors: Szucs Thomas D. , Blank Patricia R. , Schwenkglenks Matthias 
Published: October 2019

Abstract
Abstract 1372
Poster Board I-394

Background:
Erythropoiesis-stimulating agents (ESA) are widely used in the treatment of chemotherapy-induced anemia (CIA). ESA prescription has come under pressure in this indication due to safety concerns and because of their high acquisition price. Recent studies suggest that the efficiency of ESA can be maximized by optimising iron stores and iron bioavailability. However, little is known about the economic implications of adding intravenous ferric carboxymaltose (iv FCM; an innovative iv iron formulation allowing the administration of high iron dosages in a short time) to ESA treatment.

Aims:
This study aimed at estimating the incremental cost-effectiveness of adding iv FCM to ESA treatment in patients with CIA, in the Swiss health care setting.

Methods:
Using a Swiss third party perspective, incremental cost effectiveness of iv FCM use was expressed as cost per additional CIA patient responding to anemia treatment. Response rates and medical resource use parameters were retrieved as weighted averages from 4 randomised controlled clinical trials of solid tumour patients, which used other iv iron preparations. An assumption of equal clinical effectiveness was made. Mean treatment duration was 11.9 weeks. Unit costs were based on average ex-factory prices for ESAs. The European target ex-factory price for 100 mg iv FCM was €25.

Results:
Per-patient costs were determined to be €4'943 for ESA treatment alone and €5'227 for ESA plus iv FCM. The addition of iv iron to ESA increased the response rate from 55% to 74%. Hence, the incremental cost-effectiveness (cost per additional patient responding to treatment) for iv FCM was estimated at €1′455.

Summary/conclusions:
The addition of iv FCM to ESA treatment appears to be economically viable in patients with CIA, on the basis of a marked increase in response rate due to iv iron use. Additional economic analyses are certainly warranted, as soon as appropriate clinical data become available. Cost savings associated with reduced administration time are not covered by this analysis.

Disclosures:
Schwenkglenks: Amgen: Honoraria, Research Funding.