bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Dose Therapy Improves Survival in Systemic Light Chain Amyloidosis: 14 Year Follow up
Authors: Parmar Simrit , Howell Joshua , Wang Michael , Khan Mubeen A , Bashir Qaiser , Shah Jatin J. , Shah Nina , Popat Uday R. , Giralt Sergio A , Orlowski Robert Z. , Qazilbash Muzaffar 
Published: October 2019

Abstract
Abstract 750

Background:
Treatment remains a challenge for systemic light chain amyloidosis (AL). Autologous stem cell transplant (AutoSCT) has been associated with long term survival. However, a recent multicenter randomized study failed to show survival benefit for AutoSCT perhaps due to high non-relapse mortality (NRM). Here we present a comparison of AutoSCT to other conventional therapies in AL patients treated at our institution with a 14-year follow up.

Methods:
A total of 2018 cases were identified upon pathology review from 1998–2012. AL was confirmed in 264 patients; primary amyloidosis (PA) in 147 pts and multiple myeloma with amyloidosis (AM) in 110 patients; solitary amyloidoma in 7 patients. AutoSCT was performed in 126 patients (PA=79 and AM=47).

Results:
The day 100 NRM was 5% and 1-year NRM was 8%. With a follow up of 14 years in surviving patients, the 10-year overall survival (OS) of AL patients was significantly better in those undergoing AutoSCT (41% vs. 17%; p<0.0001; figure 1). Involvement of more than one organ (6-yr OS 36% vs. 55%; p=0.04) and cardiac involvement (2-yr OS of 57% vs. 78%; p=0.01) were associated with poor outcome. In the patients undergoing AutoSCT: PA vs. AM, Mayo staging, Boston University (BU) staging or bone marrow plasma cells >10 % at the time of autoSCT did not have an impact on OS. Cardiac biomarkers including NT-ProBNP and Troponin-I and T levels were available in a limited number of patients and were not analyzed for survival outcomes. In multivariate analysis, superior OS was associated with: age <60yrs (HR 2.1, p=0.022); and induction treatment before AutoSCT (HR 2.7, p=0.02). Involvement of kidney as the only end organ showed a trend toward improved survival (HR 1.6, p=0.06) (Table 1). Specifically for PA patients (n=79); treatment before autoSCT was associated with improved 3-yr OS: 85% vs. 66%; p=0.02.

Conclusions:
AL patients should be evaluated for AutoSCT and selected patients should undergo induction therapy to decrease amyloid burden prior to AutoSCT.

Disclosures:
No relevant conflicts of interest to declare.
CD4 Cells Engineered to Express an MHC Class I Restricted TCR Can Rescue CD8 Cells Tolerized to Tumour-Associated Antigens
Authors: Ghorashian Sara , Carpenter Ben , Holler Angelika , Nicholson Emma , Ahmadi Maryam , Zech Mathias , Bennett Clare , Xue Shao-An , Morris Emma , Stauss Hans , Chakraverty Ronjon 
Published: October 2019

Abstract
Abstract 952

Background:
The efficacy of T cell therapies for cancer may be limited when targeting tumour-associated antigens (TAA) which are also self-antigens. Ongoing exposure to TAA on normal cells may lead to tolerance via anergy or exhaustion of antigen-specific T cells.

Methods:
We have designed a model of tolerance to TAA in which T cell receptor (TCR)-transduced CD8 T cells recognise pMDM2, a TAA that is also a ubiquitous self-antigen. CD8+ T cells were transduced with pMDM2-specific TCR (MDM-CD8) and transferred to sub-lethally irradiated B6 mice that express pMDM2 in the context of MHC Class I (H2-Kb). MDM-CD8 cells are detectable 4 weeks after transfer but show defective in vivo killing of target cells pulsed with MDM2 peptide. We have used this model to determine the mechanism of tolerance and to evaluate whether tolerant CD8+ T cells can be rescued by CD4 help.

Results:
To determine whether tolerance of MDM-CD8 cells was dependent upon recognition of cognate antigen, we transferred MDM-CD8 cells into mice of a different MHC background (BALB/c) which lack H2-Kb required for presentation of the TCR-recognised MDM2 peptide. When BALB/c MDM-CD8 cells were transferred to BALBc hosts their functions were preserved and they retained efficient antigen-specific cytolysis.
To determine whether tolerance could be modified by provision of CD4+ T cell help, we co-transferred MDM-CD8 with transgenic OT-II CD4+ cells. OT-II cells were primed with dendritic cells (DCs) loaded with cognate pOVA323-339 or irrelevant peptide. When activated through their TCR, OT-II cells increased both the frequency of MDM2-specific CD8 cells and their cytotoxic functions, indicating that CD4 help can overcome CD8 tolerance to TAA.
Ineffective antigen presentation to CD4 cells and lack of known MHC class II-restricted TAA are major limitations to providing CD4 help in T cell therapy for cancer. We therefore tested whether transfer of the MHC Class I-restricted MDM2 TCR into CD4 cells could provide help upon transfer to antigen-expressing hosts. Co-transfer of MDM2-TCR-transduced CD4 cells with CD8 cells improved antigen-specific killing of target cells when compared to single transfer of either TCR-transduced CD8 or CD4 cells.

Conclusion:
CD4 cells rendered capable of responding to an MHC class I restricted TAA by TCR transfer can rescue tolerance developing in a CD8 population with the same specificity. This is potentially a novel way to circumvent defective immune responses arising in adoptively transferred effector cells due to prolonged exposure to cognate antigen on normal host cells.

Disclosures:
Stauss: Cell Medica: Scientific Advisor Other.
Pathway Mutations in the Splicing Machinery in Myeloid Neoplasms
Authors: Ogawa Seishi 
Published: October 2019

Abstract
Abstract SCI-14
During the past decade, significant progress has been made in our understanding of the molecular pathogenesis of myelodysplastic syndromes (MDS) and related myeloid neoplasms, in which one of the major findings was frequent mutations of genes in epigenetic regulation, such as DNA methylation (DNMT3A, TET2, and IDH1/2) and chromatin modifications (ASXL1, EZH2, EED, and SUZ12). They are also found in comparable or even higher fractions of other myeloid neoplasms, underscoring the common impact of deregulated epigenetic regulation on myeloid leukemogenesis. On the other hand, a new class of pathway mutations has been uncovered recently that commonly involve the RNA splicing machinery (1, 2, 3). Thus, at least eight different components of the machinery, invariably engaged in the 3' splice site recognition, have been reported to be mutated in as high as 45 percent to 85 percent of cases with different subtypes of MDS and related myeloid neoplasms mostly in a mutually exclusive manner. This indicates that the 3' splice site recognition is the functional target of these mutations. There exist discrete mutational hotspots in three out of four major targets, including SF3B1, SRSF2, U2AF35, and ZRSR2, and these mutant alleles can induce abnormal RNA splicing, indicating the gain-of-function nature of the mutations (2). Splicing factor mutations are largely specific to myelodysplasia phenotypes but relatively rare in acute myeloid leukemia and myeloproliferative neoplasms (2), suggesting their primary roles in the pathogenesis of myelodysplasia. The genotype-phenotype association is especially prominent in the case of SF3B1 mutations, which were found in 76 percent to 83 percent of cases of refractory anemia with ringed sideroblasts (RARS), refractory anemia with ringed sideroblasts associated with marked thrombocytosis (RARS-T), and refractory cytopenia with multilineage dysplasia and ringed sideroblasts (RCMD-RS) (1, 2). In this session, the updated findings on the spliceosome mutations found in myelodysplasia, including their clinical and functional aspects, will be discussed.

Disclosures:
No relevant conflicts of interest to declare.
Primitive and Definitive Erythropoiesis
Authors: Palis James 
Published: October 2019

Abstract
Abstract SCI-37
Studies in mammalian and nonmammalian vertebrate embryos indicate that erythropoiesis comes in two flavors: primitive and definitive. The primitive erythroid lineage in mammalian embryos is characterized by a transient wave of lineage-committed progenitors that emerge from the yolk sac and generate a wave of precursors that synchronously mature in the bloodstream. Primitive erythroid precursors dynamically regulate embryonic globin gene expression and ultimately enucleate to form erythrocytes. Primitive erythropoiesis is superseded by definitive erythroid cells that mature extravascularly in association with macrophage cells. Studies in the mouse embryo indicate that definitive erythropoiesis has two distinct developmental origins. The first is a transient wave of erythro-myeloid progenitors (EMP) that emerge from the yolk sac and seed the early fetal liver. The second is a long-term program of erythropoiesis derived from hematopoietic stem cells. Erythropoietin is the central regulator of definitive erythropoiesis, in part by regulating the survival of committed progenitors. In contrast, the role of erythropoietin in primitive erythropoiesis remains poorly understood. Recent studies indicate that erythropoietin does not regulate the primitive erythroid progenitor compartment, but rather plays a critical role in establishing an antiapoptotic state during the terminal maturation of primitive erythroblasts. EMP-derived proerythroblasts are capable of extensive self-renewal in vitro, while primitive erythroid progenitors are incapable of self-renewal under the same conditions. These studies, taken together, indicate that the primitive and definitive forms of erythropoiesis have fundamental differences in the regulation of red cell output. The overlapping emergence of primitive and definitive erythroid lineages in differentiating embryonic stem cells suggests that the transient yolk-sac-derived primitive and EMP-derived definitive erythroid programs are recapitulated in vitro. These studies offer the hope that human embryonic stem cells can serve as a source of functional definitive erythroid cells for transfusion therapy.

Disclosures:
No relevant conflicts of interest to declare.
Autoantibody Epitope Mapping By Hydrogen-Deuterium Exchange Mass Spectrometry at Nearly Single Amino Acid Residue Resolution Reveals Novel Exosites on ADAMTS13 Critical for Substrate Recognition and Mechanism of Autoimmune Thrombotic Thrombocytopenic Purpura
Authors: Casina Veronica C. , Hu Wenbing , Hanby Hayley A. , Pickens Brandy , Mayne Leland , Ostertag Eric , Kacir Stephen , Siegel Don L. , Englander S. Walter , Zheng X. Long 
Published: October 2019

Abstract
Acquired thrombotic thrombocytopenic purpura (TTP), a potentially fatal arterial thrombotic disorder, is primarily caused by autoantibodies that bind and inhibit plasma von Willebrand factor (VWF)-cleaving metalloprotease (ADAMTS13) activity. However, the mechanisms underlying autoantibody-mediated inhibition of ADAMTS13 activity and acquired TTP are not fully understood. By a hydrogen-deuterium exchange coupled with mass spectrometry (HX-MS) technique, we found that human monoclonal anti-ADAMTS13 antibodies, the single chain variable region fragments (scFvs)4-20, 4-16, and 3-1 that were, isolated by phage display from two patients with acquired TTP, predominantly bound to a discontinuous and conformational epitope in the spacer domain of ADAMTS13 with a subtle difference. The epitope for scFvs4-20 and 4-16 comprises five small flexible loops, including a previously described motif A (or exosite 3, R659-E664), motif B (exosite 4, L632-R639), and several other outlying residues (F592, Y658, and Y665), while scFv3-1 bound all other residues except for those in motif A. Site-directed mutagenesis and biochemical analysis demonstrated that both motifs A and B were found to be critical for recognition and proteolysis of VWF73 and multimeric VWF. Deletion of motif A or motif B in full-length ADAMTS13 abolished the binding of scFvs4-20 and 4-16 but not 3-1 (which did not bind motif A). Our findings demonstrate the powerful use of HX-MS for mapping antibody epitopes at nearly single amino acid resolution. This provides a new way to reveal mechanisms of autoantibody-mediated inhibition of plasma ADAMTS13 activity and acquired TTP.
Figure 1 Figure 1.

Disclosures
No relevant conflicts of interest to declare.
Von Willebrand Factor Is a Cofactor in Complement Regulation
Authors: Feng Shuju , Kroll Michael H. , Afshar-Kharghan Vahid 
Published: October 2019

Complement, besides its involvement in eliminating microbes, participates in such diverse processes as synapse maturation, clearance of immune complexes, angiogenesis and tissue regeneration. Delicate balance between complement activation and regulation contributes to complement’s role in physiology. Any trigger that tips this balance can induce self-attack. Atypical hemolytic uremic syndrome (aHUS) is a systemic disease characterized by non-immune hemolytic anemia, thrombocytopenia, and renal impairment. In over 50% of cases, aHUS is known to be caused by uncontrolled activation of the complements.
Von Willebrand factor (VWF) is a large multimeric glycoprotein that plays an important role in stopping the escape of blood from vessels following vascular injury. VWF and VWF cleavage enzyme ADAMTS13 gene defects have been identified in patients with aHUS, raising the possibility that VWF could have contributed to complement regulation. To examine the role of VWF in complement activation, we investigated whether VWF functions as a cofactor for FI-mediated C3b cleavage through in vitro assay. We found that C3b binds to VWF. In the presence of plasma-purified VWF (pVWF), FI cleaves C3b to 68kD and 43kD degradation products (iC3b) (Figure (A)). VWF alone, or FI alone, did not have any effect on C3b cleavage. C3b, not C3 or iC3b, was the mainly substrate for FI/VWF proteolysis. Increasing VWF concentration or prolonging the incubation time with VWF enhanced FI-mediated C3b cleavage. To remove the possibility that another plasma protein co-purified with pVWF that affects our results, we used recombinant VWF dimers purified from human embryonic kidney (HEK) 293 cell expressing VWF-Dpro cDNA, and detected a similar cofactor activity (Figure (B)).To investigate whether the size of VWF multimers have any effect on C3b cleavage, we compared the cofactor activity of pVWF, recombinant VWF dimers, and ULVWF multimers. While pVWF and dimer VWF enhanced C3b cleavage by FI, ULVWF did not have any effect on C3b cleavage (Figure (B)). In plasma, complement proteins Factor B and Factor D coexist with the inhibitory protein FI. To investigate the effect of VWF on complement activity in the presence of both pro-activation and inhibitory complement proteins, we incubated C3, FB, FD, and FI with VWF. In the presence of FB and FD, C3 be activated and resulted in the generation of C3a and C3b. Addition of recombinant VWF put a brake on complement activation and shifted C3 toward the generation of iC3b (Figure (C)). We conclude that normal plasma VWF, function as a cofactor, prevents complement activation through steers the complement pathway toward the generation of inactive iC3b. ULVWF multimers, as are present in patients with thrombotic microangiopathy, lack an inhibitory effect on complement and permit complement activation.
Figure 1 Figure 1.

Disclosures
No relevant conflicts of interest to declare.
Matched and Mismatched Unrelated Donor Versus Unmanipulated Haploidentical Donors for Hematopoietic Cell Transplantation in Acute Leukemia in Remission: A Pair Matched Analysis on Behalf of the Acute Leukemia Working Party (ALWP) of the European Society for Blood and Marrow Transplantation (EBMT)
Authors: Piemontese Simona , Ciceri Fabio , Labopin Myriam , Arcese William , Kyrcz-Krzemien Slawomira , Santarone Stella , Huang He , Beelen Dietrich , Gorin Norbert Claude , Craddock Charles , Gulbas Zafer , Bacigalupo Andrea , Nagler Arnon , Mothy Mohamad 
Published: October 2019

Abstract
Background. The best donor source for adult patients with acute leukemia lacking an HLA-identical donor still remains to be established. The objective of this study was to compare the outcome after T-cell-replete hematopoietic stem cell transplantation from haploidentical donor (HAPLO) and transplant from Matched Unrelated Donor (MUD) or Mismatched Unrelated Donor at a single HLA-locus (MMUD) for patients with acute leukemia in remission.
Methods. From January 2007 to December 2012, 313 consecutive HAPLOs were performed as first allogeneic transplants in adult patients with de novo acute leukemia in CR1 or CR2 and reported to the EBMT Registry. We were able to pair match 273 of these 313 patients with another 273 patients who received a MUD and 273 who received a MMUD transplant. The matching factors were as follow: age (+/-5y), diagnosis (myeloid or lymphoblastic leukemia), disease status at transplant (CR1 or CR2) and interval from diagnosis to transplant (+/-1mo).
Results. The median follow-up was 22 months. The two-year non-relapse mortality (NRM) and relapse (RI) cumulative incidences were 28% and 30% for HAPLO, 21% and 19% for MUD, and 28% and 27% for MMUD. The two-year KM estimates of leukemia-free survival (LFS) and overall survival (OS) were 42% and 49% for HAPLO, 59% and 65% for MUD, 45% and 51% for MMUD. In multivariate analysis both NRM and RI were significantly reduced in MUD compared to HAPLO (NRM, hazard ratio (HR): 0.61, p=0.02, 95%CI: 0.40-0.91; RI, HR: 0.59, p=0.01, 95%CI: 0.39-0.89) but there was no statistical difference between HAPLO and MMUD (NRM, p=0.59; RI, p=0.52). LFS and OS were significantly higher in MUD compared to HAPLO (LFS HR: 0.61, p=0.001, 95%CI: 0.45-0.81.OS HR: 0.63, p=0.004, 95%CI: 0.46-0.86) but not statistically different between MMUD and HAPLO (LFS, p=0.45. OS, p=0.84). Of note, type of donor was neither associated with day-100 grade II-IV acute graft-versus-host disease, nor to chronic graft-versus-host disease.
Conclusion. These findings suggest that LFS and OS were significantly higher in patients with acute leukemia in remission receiving a MUD compared to patients with similar characteristics receiving a HAPLO. We didn’t find significant differences between MMUD and HAPLO. In the absence of a MUD, host/donor features and urgency of transplant should drive us towards the best choice between these alternative donor sources.

Disclosures
No relevant conflicts of interest to declare.
Haplo-Cord Transplantation Vs Unrelated Donor Stem Cell Transplantation in Patients with AML/MDS Older Than 50
Authors: Rhodes Joanna , van Besien Koen , Liu Hongtao , Gergis Usama , Tsai Stephanie B. , Mayer Sebastian , Stock Wendy , Larson Richard A. , Shore Tsiporah B. , Odenike Olatoyosi , Pearse Roger , Godley Lucy A , Mark Tomer M , Kline Justin , Bishop Michael R. , Artz Andrew S. 
Published: October 2019

Abstract
Haplo-cord Transplantation Vs Unrelated Donor Stem Cell Transplantation In Patients with AML/MDS older than 50
Between 2007 and 2013, 109 patients with AML/MDS who were 50 years and older and had no HLA- matched related donor underwent allogeneic hematopoietic stem cell transplant. 64 had an HLA identical unrelated donor and received fludarabine/melphalan/alemtuzumab conditioning and post transplant tacrolimus for graft vs host disease (GVHD) prophylaxis. 45 underwent haplo-cord (HC) SCT with fludarabine/melphalan/ thymoglobulin; post-transplant tacrolimus and MMF. We compared patient characteristics and transplant outcomes between both groups. (Table 1) Age distribution and ASBMT risk category were similar. There were more patient's with AML in the HC group. (P=0.01) Time to neutrophil recovery, treatment related mortality (TRM), relapse rate, progression free survival (PFS) and overall survival (OS) were nearly identical between the two groups. Time to platelet recovery was on average 5 days longer after HC (p=0.05) The incidences of acute and chronic GVHD were very low in both groups, in part due to the use of in-vivo T cell depletion.
HC transplant with reduced intensity conditioning is a curative treatment for older patients with AML/MDS who lack HLA identical unrelated donors. Despite inclusion of many patients with high risk features, nearly two thirds were estimated to be alive one year after transplant and very few had chronic GVHD. Haplo-cord grafts are more readily available, a potential advantage over MUD grafts in situations where transplant is needed urgently. TableMatched Unrelated DonorHaplo Cord PN6445Age (range)62 (50-73)62 (50-74)AML/MDS45/2041/5 0.01ASBMTLow/Int /High21/6/3015/10/200.7KPS 9090Time to ANC >50010110.1Time to Plt >2018230.05PFS@ 1 Y (95% CI)46 (34-58)41 (26-56)0.6OS@ 1 Y (95% CI)57 (44-70)64 (49-79)0.8Cum Inc TRM @100 d (95% CI)9 (2-16)9 (0-18)0.2Cum Inc TRM @ 1 Y(95% CI)25 (14-36)29 (15-44)0.2Cum Inc Relapse @ 1Y (95% CI)30 (18-42)26 (12-40)0.5Cum Inc AGVHD @ 100 D (95% CI)25 (14-36)29 (13-43)0.7Cum Inc CGVHD @ 1 Y (95% CI)6 (0-12)7 (0-15)0.9

Disclosures
van Besien: Miltenyi: Research Funding. Mark:Millennium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Onyx: Research Funding, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Artz:Miltenyi: Research Funding.
A Mouse Model for XLP-2 Disease Uncovers a Critical Function for IL-1beta and TNF in Driving Hyper-Inflammation
Authors: Jost Philipp J. , Yabal Monica , Adler Heiko , Knies Nathalie , Groß Christina , Damgaard Rune Busk , Kanegane Hirokazu , Peschel Christian , Strasser Andreas , Groß Olaf , Ruland Jürgen , Gyrd-Hansen Mads 
Published: October 2019

Abstract
The hyper-inflammatory syndrome X-linked lymphoproliferative syndrome type 2 (XLP-2) is defined by mutations in BIRC4 (XIAP). XLP-2 is often diagnosed in paediatric patients and is characterized by hyper-inflammation triggered by common viral infections. Symptoms include splenomegaly, HLH, fevers, and chronic haemorrhagic colitis among others. Recent work has also shown that mutations in BIRC4 predispose to the development of early-onset IBD, which is not necessarily associated with symptoms of systemic hyper-inflammation. Symptoms of XLP-2 are mostly attributed to the aberrant activation of macrophages and dendritic cells (DC) and the subsequent accumulation of activated T-lymphocytes.
We have characterized the inflammatory response of mice deficient for BIRC4 (XIAP) to viral infections with the murine herpes virus 68 (MHV-68) as the closest murine model for human EBV-driven mononucleosis. Xiap-/- mice were capable of clearing the virus normally during early infection (day 6, 16), but failed to do so during the course of the infection measured as elevated viral genomic loads during late (day 43) and very late (day 84) latency. Xiap-/- mice responded to intranasal application of the virus with systemic hyper-inflammation exemplified by elevated IL-1beta levels, splenomegaly and increased activation of peripheral T lymphocytes such as CD4+ effector T cells, regulatory T cells (Treg), and IFNg+ T cells. In previous work, we have shown that TNF is critically required to drive the hyper-inflammatory phenotype of macrophages and dendritic cells of XIAP-deficient mice. Indeed, genetic deletion of TNF in vivo or, alternatively, anti-TNF treatment in vivo using Eternacept (Enbrel) ameliorated the symptoms of XIAP-deficient mice in response to viral infection.
Elevated IL-1beta levels were also observed in human peripheral blood-derived monocytes from XLP-2 patients (7 patients from 5 different families) when compared to healthy controls. In conclusion, this data supports the notion that anti-TNF treatment might be able to ameliorate the hyper-inflammatory responses in XLP-2 patients, when used early during an infection.

Disclosures
No relevant conflicts of interest to declare.