bluuebunny/crossref_metadata_2025_split huggingface dataset:
CXCR4 Inhibitors Selectively Eliminate CXCR4 Expressing Human Acute Myeloid Leukemia Cells in NOG Mouse Model
Authors: Zhang Yanyan , Patel Satyananda , Wittner Monika , De Botton Stephane , Solary Eric , Vainchenker William , Coppo Paul , Louache Fawzia 
Published: October 2019

Abstract
Abstract 1881
The chemokine receptor CXCR4 favors the interaction of acute myeloid leukemia (AML) cells with their niche but the extent to which it participates to pathogenesis is unclear. Here we show that CXCR4 expression at the surface of leukemic cells allowed distinguishing CXCR4high (25/47; 53%) from CXCR4neg/low (22/47, 47%) AML patients. Leukemic engraftment in NOD/Shi-scid/IL-2Rnull (NOG) mice was observed for both the CXCR4high and CXCR4neg/low groups. When high levels of CXCR4 are expressed at the surface of AML cells, blocking the receptor function with small molecule inhibitors could promote leukemic cell death and reduce NOG leukemia-initiating cells (LICs). Conversely, these drugs had no efficacy when AML cells do not express CXCR4 or when they do not respond to CXCL12. Mechanisms of this anti-leukemic effect included interference with the retention of LICs with their supportive bone marrow microenvironment niches, as indicated by a mobilization of LICs in response to drugs, and increased apoptosis of leukemic cells in vitro and in vivo. CXCR4 expression level on AML blast cells and their migratory response to CXCL12 are therefore predictive of the response to the inhibitors and could be used as biomarkers to select patients that could potentially benefit from the drugs.

Disclosures:
No relevant conflicts of interest to declare.
Double Haploidentical Hematopoietic Stem Cell Transplantation (HSCT) Enhances Anti-Tumor Activity After Transplant
Authors: Budak-Alpdogan Tulin , Bailey Cavan P , Panis Michelle , Sauter Christopher , Agrawal Vikas , Biswas Chandra , Flomenberg Neal , Alpdogan Onder 
Published: October 2019

Abstract
Abstract 1897
We have previously shown that haploidentical (HI) HSCT with low dose donor T-cell infusion provides a survival advantage in tumor bearing mice when compared to parent F1 or MHC-matched transplant models. We suggest that MHC difference in HI-HSCT generates early T-cell clonal activation against the unshared MHC haplotype, which eliminates residual tumor cells that express the unshared MHC haplotype. However, alteration in MHC antigen expression is a significant contributor to tumor escape from graft-versus-tumor (GVT) activity. Recent haploidentical transplant data revealed that uniparental disomy, the loss of the HLA haplotype, is a clinically relevant mechanism of tumor escape that leads to post-transplant leukemia relapse. Murine renal cell carcinoma, RENCA-TGL, cell line normally expresses only H2Kd as a MHC molecule. Therefore, in our haploidentical transplant model, T cell clonal activity is usually restricted against H2Kd molecule only. For circumventing the single haplotype expression of tumor model, we transfected this cell line with a H2Kb expressing vector, pAcGFP-NeoR-H2Kb, and generated stable clones with G418 selection. The clone that has more than 95% H2Kb expression used for in vivo experiments. Both tumor cell lines, i.e. parental and transfected clone, had similar in vivo tumor growth acceptance and growth rate. We then used two different haploidentical donors that were targeting different MHC haplotypes. Lethally irradiated B6D2F1 (H2Kb/d) mice were transplanted with T cell depleted bone marrow (TCD-BM) from either B6C3F1 (H-2Kb/k) (single haplo-1; SH1), or C3D2F1 (H2Kk/d) (single haplo 2; SH2) or both donor mice with low-dose (1×105) T-cells. In some experiments, animals were also injected either H2Kd or H2Kb/d expressing RENCA-TGL cells for the evaluation of GVT activity.
Bone marrow (BM), spleens and thymi were harvested from recipients of single and double HI-HSCT at day 35 and showed similar cellularities. Interestingly, spleen and bone marrow had similar chimerism from both donors in DH-HSCT. There were no early transplant mortality, graft failure, weight loss and GVHD scoring difference among the double or single-haploidentical transplant recipients. In two other sets of experiments, we followed the tumor growth and the survival of tumor bearing mice after transplant. The recipients of DH-HSCT showed a better survival and GVT activity than the recipients of SH-HSCT in RENCA-TGL (H2Kb/d) bearing tumor model. These observations confirmed that MHC targeting plays a prominent role in tumor surveillance, and immune targeting the unshared MHC haplotype with haploidentical transplant induce remarkable survival advantage. Double HI-HSCT provides an unique anti-tumor activity that continues to exert GVT effect, even in case of MHC haplotype loss.

Disclosures:
No relevant conflicts of interest to declare.
Post-Transplant Pulmonary Function Abnormalities Normalize in Survivors by the Second Decade After Allogeneic Stem Cell Transplantation
Authors: Jain Natasha A , Koklanaris Eleftheria K. , Chawla Kamna , Pophali Priyanka A , Klotz Jeffrey K. , Hourigan Christopher S. , Savani Bipin N. , Ito Sawa , Barrett A. John , Battiwalla Minoo 
Published: October 2019

Abstract
Abstract 1967
Following allogeneic stem cell transplant (SCT), late-onset severe pulmonary complications occur in more than 10% of patients and confer an increased risk of mortality in the first few years post transplant. Whether pulmonary repair can occur subsequently is not well characterized. We prospectively collected pulmonary data on 138 (60 female, 78 male) recipients of allogeneic SCT from HLA identical siblings surviving > 5 years. The median age at transplant was 36 years. Indications for transplant were CML (63), AML (31), MDS (19), ALL (12) and others (14). 126 patients received ≥1200 cGy TBI-based conditioning with or without lung shielding, 3 received 400 cGy TBI-based conditioning and 9 patients received no irradiation. The graft was ex vivo T cell depleted in 131 recipients except six who received non-myeloablative SCT. Of the survivors, 26 had no cGvHD, 70 had cGvHD lasting less than 3 years and 42 had prolonged cGvHD requiring systemic immunosuppression for more than 3 years. Of the 17 patients who died beyond 5 years, 4 died of pulmonary causes, including two with lung cancer. Pre-transplant abnormalities (< 80% predicted) in PFTs were found in 15.9% of subjects in the following declining frequency: FVC%, VC, TLC, FEV1, DLCO_Adj (adjusted for hemoglobin and alveolar ventilation) Hb/VA and FEV1/FVC. Baseline (BL) PFTs served as the reference for all subsequent measurements at 5, 10 and 15 years for each survivor. The only parameter showing a clinically significant decline post transplant was DLCO_Adj at the 5-year mark, with subsequent normalization [paired t-test]. The median DLCO_Adj at 5, 10 and 15 years were 88%(p<0.001), 98%(p=NS) and 100%(p=NS) of BL, respectively. Multivariable modeling (forward-stepwise multiple regression) identified the presence of chronic GVHD (p=0.017) and abnormal BL DLCO_Adj (P=0.023) as the only factors associated with the decline in DLCO_Adj at 5 years but excluded smoking, conditioning intensity, TBI dose to the lungs and demographic variables. In conclusion, poor pulmonary function as measured by DLCO_Adj within 5 years of SCT can normalize by 10 years. Chronic GVHD and pretransplant DLCO_Adj are important contributory factors.

Disclosures:
No relevant conflicts of interest to declare.
Are Disparities in Acute Myelogenous Leukemia Due to Poor Prognostic Factors At Diagnosis? A National Study
Authors: Patel Manali I. , Ma Yifei , Mitchell Beverly S. , Rhoads Kim 
Published: October 2019

Abstract
Abstract 2061

Background:
Disparities in Acute myelogenous leukemia (AML) have been described but not studied extensively in adults. Younger age at diagnosis and cytogenetic profiles of t(8;21) and acute promyelocytic leukemia (APL) subtypes of AML have been associated with improved survival from AML but no studies to date have evaluated these factors by race. The purpose of the current study is to evaluate differences by race/ethnicity in age and select cytogenetic factors at diagnosis. The hypothesis is that disparities for minorities will be explained by older age at diagnosis and lower rates of select favorable cytogenetics.

Methods:
Patients with AML were identified in the Surveillance Epidemiology End Results (SEER) database during the years 1999–2008. Kaplan-Meier survival curves were generated to predict survival by race/ethnicity, stratified by age. Multivariable Cox proportional hazard models estimated mortality by race with adjustment for age, gender, year of diagnosis, t(8;21) and APL subtypes.

Results:
A total of 27,252 patients were included in the study. Blacks and Hispanics were diagnosed at younger ages (<61 years) and had higher rates of t(8;21) and APL compared with non-Hispanic Whites (NHW). The overall KM curve demonstrates that NHWs had a worse survival compared to other races/ethnicities. However when KM curves were stratified by age, blacks and Hispanics had worse survival in every age category below age 61. In multivariable models adjusted for age, black patients had an increased risk of death compared to NHWs (HR 1.10 95% CI (1.04–1.16). In multivariable models adjusted for t(8;21) and APL subtypes, there was no attenuation for the disparity. For APL subtype, in particular, there was an increased disparity for blacks (HR 1.11 95% CI (1.05–1.17) and Hispanics (HR 1.05 95% CI (1.01–1.11) compared to NHWs.

Conclusions:
Despite younger age and higher prevalence of favorable cytogenetics, blacks have worse mortality from AML compared to other racial/ethnic groups. Blacks and Hispanics with the APL subtype have worse mortality compared to other racial/ethnic groups. Future studies should investigate other reasons for disparities among black and Hispanics with acute myelogenous leukemia.

Disclosures:
No relevant conflicts of interest to declare.
Quality Improvement Goals for Sickle Cell Disease Pain Management in an Urban Pediatric Emergency Department: We Can Do Better!.
Authors: Morris Claudia R. , Barreda Fernando , Leibovich Sara A. , Rutherford Mary , Saulys Augusta , Stewart Melinee , Lavrisha Lisa , Vichinsky Elliott , Bell Michael , Treadwell Marsha J 
Published: October 2019

Abstract
Abstract 2101

Background.
Vaso-occlusive painful episodes (VOE) are the leading cause of hospitalizations and emergency department (ED) visits in sickle cell disease (SCD), and are associated with increased mortality. Although disparities specific to pain management practices in the ED for children with SCD have not been identified, ethnic disparities in ED care have been reported, & adults with SCD experience longer delays in the initiation of analgesics compared to other patients with pain. However, initiation of treatment in the ED is often delayed as a result of random events that are beyond anyone's control, such as high patient volumes & acuity of other patients in the ED, even when policies are in place for immediate triage of patients with SCD & pain. In a recent study of children with SCD, median time from arrival to analgesia administration was 90 minutes, with high ED census as the biggest culprit for delays. Barriers to rapid care in the ED are common across the country, including overcrowding, nursing ratios, insufficient staff coverage, inadequate funding, & slow flow of patients from the ED to the wards in addition to patient acuity.

Methods.
As part of a quality improvement (QI) project to improve management of SCD pain in the ED at Children's Hospital & Research Center Oakland, we are reviewing quality indicators to determine areas that can be targeted for improvement. ED-based data was collected and analyzed from a sample of 47 patients initially evaluated in the ED and enrolled in a randomized, placebo-control trial of argininetherapy for children with SCD hospitalized for VOE between years 2000–2008, and compared to recent data in 2012 of 55 ED visits for VOE (66% admissions) to identify trends in practice in our ED.

Results.
See Table 1.

Conclusions.
To these authors' surprise, children with SCD commonly experienced delays in pain management in the ED. These trends have not changed dramatically over a decade, and are not likely to be unique to our facility. Areas to target for improvement include time of arrival to parenteral pioid administration, in particular, time from ED room placement to placement of intravenous catheter. Utilizing intranasal fentanyl in the ED for acute pain is one novel intervention that should significantly decrease time to initial pain management. These reported data will be used as baseline quality measures for comparison to determine the success of QI initiatives such as a refined pain management algorithm on ED-based clinical outcomes.

Disclosures:
No relevant conflicts of interest to declare.
Bimodal Induction of NK Cell Reactivity Against Acute Myeloid (AML) and Chronic Lymphoid Leukemia (CLL) by Fc-Engineered GITR-Fc Fusion Proteins.
Authors: Steinbacher Julia , Schmiedel Benjamin J , Werner Antje , Nuebling Tina , Buechele Corina , Grosse-Hovest Ludger , Kanz Lothar , Salih Helmut R 
Published: October 2019

Abstract
Abstract 2143
NK cells play an important role in anti-tumor immunity and largely contribute to the efficacy of therapeutic strategies like allogenic stem cell transplantation in AML and application of Rituximab that induces antibody-dependent cellular cytotoxicity (ADCC) in CLL. Recently, we demonstrated that the TNF family member GITR ligand (GITRL) is expressed on leukemia cells in a high proportion of AML and CLL patients and impairs direct and Rituximab-induced reactivity of NK cells which constitutively express its counterpart GITR (e.g., Buechele et al., Leukemia 2012). Here we developed a strategy to reinforce NK anti-leukemia reactivity by combining disruption of NK-inhibitory GITR-GITRL interaction with induction of ADCC against the GITRL-expressing leukemia cells using GITR-Ig fusion proteins with modified Fc moieties. Fc parts were engineered by amino acid exchange as previously described (Lazar et al., PNAS 2006; Armour et al., Eur. J. Immunol. 1999). Compared to wild type GITR-Ig (GITR-Fc-WT), our mutants (S239D/I332E and E233P/L234V/L235A/deltaG236/A327G/A330S) displayed highly enhanced (GITR-Fc-ADCC) and abrogated (GITR-Fc-KO) affinity to the Fc(gamma)RIIIa receptor (CD16) expressed on NK cells, respectively. In functional analyses of NK cells and primary leukemia cells, GITR-Fc-KO, which does not induce ADCC, already increased NK reactivity due to disruption of GITR-GITRL interaction. Treatment with GITR-Fc-WT further enhanced NK reactivity due to modest induction of ADCC, while GITR-Fc-ADCC induced highly increased NK-mediated target cell lysis, degranulation and cytokine production in a target-antigen dependent manner. With CLL cells, combined treatment with GITR-Fc-ADCC fusion protein and Rituximab caused additive effects, resulting in significantly enhanced NK cell ADCC. Notably, the effects of our fusion proteins were observed both in an allogenic setting and when employing NK cells of patients with autologous leukemia cells as targets. Our results demonstrate that Fc-engineered GITR-Fc-ADCC fusion protein may combine both neutralization of the NK-inhibitoryeffects of GITR-GITRL interaction and targeting GITRL-expressing malignant cells for NK anti-tumor reactivity and thus constitute an attractive immunotherapeutic means for the treatment of AML and CLL.

Disclosures:
No relevant conflicts of interest to declare.
The Role of IL-4 Signaling in CD8+ Innate-Like Lymphocyte Development.
Authors: Carty Shannon A. , Koretzky Gary A , Jordan Martha S 
Published: October 2019

Abstract
Abstract 2161
The innate and adaptive arms of the immune system collaborate to protect the host against invading pathogens and perform immune surveillance against malignant transformation. As key effectors of the adaptive immune system, conventional T cells develop in the thymus and exit to the periphery as naïve cells, requiring antigenic stimulation and subsequent differentiation to gain effector functions, such as cytokine secretion or cytolytic activity. In contrast to conventional T cells, non-conventional T lymphocytes possess characteristics of innate immune cells, such as expression of surface markers associated with activation/memory and acquisition of effector function during thymic development, and thus are termed innate-like lymphocytes (ILLs). Recently, an expanded population of CD8+ ILLs was identified in mice with a mutation in the T cell receptor signaling protein SLP-76 (SLP-76 Y145F mice). These CD8+ ILLs are characterized by expression of activation/memory markers CD44 and CD122, the expression of the T-box transcription factor Eomesodermin (Eomes) and rapid production of IFN-γ after ex vivo stimulation. The development of these CD8+ ILLs occurs in a cell-extrinsic manner and requires IL-4. We demonstrate that IL-4 is sufficient to upregulate Eomes expression in wild-type CD8 single-positive (SP) thymocytes in short-term in vitro culture and potentiate CD8+ ILL development in fetal thymic organ culture. Using phospho-flow cytometry, we find that CD8+ ILLs from SLP-76 Y145F mice have increased STAT6 and Akt activation vs. CD8+ non-ILLs. In CD8SP thymocytes deficient in STAT6, Eomes expression is not upregulated in response to IL-4. In addition, we demonstrate that pharmacologic inhibition of Akt in SLP-76 Y145F fetal thymic organ culture blocks CD8+ ILL development and also prevents IL-4 induced Eomes upregulation in WT CD8SP thymocytes. Importantly, we have identified CD8+ ILLs in human fetal thymocytes and umbilical cord blood and found that IL-4 is sufficient to up-regulate Eomes expression in these cells. Taken together, our data suggest that IL-4 signaling via STAT6 and Akt pathways is required for IL-4 induction of Eomes expression and CD8+ ILL development. Understanding signal transduction pathways required for CD8+ ILL development will provide insight into the development of this unique lymphocyte subset that sits at the interface between innate and adaptive immunity and has been identified in human umbilical cord blood.

Disclosures:
No relevant conflicts of interest to declare.
PAK and Akt Interactions Regulate PAR-Mediated Akt Translocation to Membrane in Platelets: A Novel PIP3-Independent Mechanism.
Authors: Badolia Rachit 
Published: October 2019

Abstract
Abstract 2166
Akt has been shown to be an important signaling molecule regulating platelet aggregation. It was proposed that Akt translocates to the membrane for its activation where it is phosphorylated on Thr308 by PDK1 and Ser473 by mTORC2. However, the specific signaling events that regulate the Akt phosphorylation and its mechanism of translocation to the membrane are not clearly defined. It has been shown that Akt phosphorylation by many agonists requires signaling events downstream of Gi activation, involving PI3-kinaseb. In addition, it was proposed that Akt translocates to the plasma membrane by binding to PIP3 (Phosphatidylinositol-3,4,5-trisphosphate) generated by PI3-kinase. Our previous studies have revealed that Gq and G12/13 pathways enhance Akt phosphorylation in platelets, suggesting a role for these pathways independently of PIP3. Hence we investigated the mechanisms of Akt translocation in platelets. Stimulation of platelets with the PAR4 activation peptide (AYPGKF) caused translocation of Akt to the membrane rapidly (as early as 20 seconds) whereas, the phosphorylation of Akt occurred at the later time points (Figure 1). Pan-phoshatidylinositide 3-kinase (PI3-Kinase) inhibitors, LY-294002 (Figure 2) and Wortmannin inhibited Ser473 phosphorylation but failed to affect translocation of Akt to the membrane indicating that Akt translocation can occur independent of PI3-kinase activity. However, translocation of Akt was dramatically inhibited in the presence of a Gq-selective inhibitor, YM254890, indicating that Akt translocation is regulated downstream of Gqsignaling pathways (Figure 3).
The p21-activated kinases (PAKs) are a family of serine/threonine kinases and are key regulators of actin polymerization and cell migration. PAK functions as a scaffolding protein and is reported to interact with numerous proteins including Akt. Here, we evaluated whether PAK activated by the Gqpathways plays a significant role in the translocation of Akt to the membrane. The co-immunoprecipitation studies revealed that Akt associates with PAK upon stimulation with AYPGKF (Figure 4). This association was abolished when platelets were pre-treated with YM254890 (Figure 5).
These results suggest that PAK1/2 activation downstream of Gq pathway mediates Akt translocation to the membrane when stimulated by PAR agonist in platelets and that this translocation is PIP3- independent.

Disclosures:
No relevant conflicts of interest to declare.
Deficient ADAMTS13 Activity in Ticlopidine-Associated Thrombotic Thrombocytopenic Purpura (TTP) in Populations From Japan in 2012: Validation of Findings Initially Reported in the United States in 1998 and 2000.
Authors: Bennett Charles , Matsumoto Masanori , Georgantopoulos Peter , Jacob Sony , Dunn Brianne L , Qureshi Zaina Parvez , Bandarenko Nicholas , Kwaan Hau C. , Winters Jeffrey , Sarode Ravindra , Kiss Joseph E , Danielson Constance , Ortel Thomas L. , Raife Thomas , Clark William F , Rock Gail , Zheng X. Long , Raisch Dennis , Fujimura Yoshihiro 
Published: October 2019

Abstract
Abstract 2203

Background:
Thrombotic thrombocytopenic purpura (TTP) is frequently characterized by severe ADAMTS13 deficiency, the cause of which is unknown. An important exception is ticlopidine-associated TTP (tc-TTP), the most common drug-induced TTP syndrome. In 1998, a possible association of TTP with ticlopidine was reported. In 1999, two additional series reported this association. In 2000, a fourth study reported severe A DAMTS13 deficiency among six of seven tc-TTP persons- suggesting a causal pathway. All of these reports were from the United States. Recently, we reported characteristics of 186 acquired idiopathic (ai)- TTP patients in Japan with severe ADAMTS13 deficiency, noting that clinical and laboratory findings for ai-TTP patients in Japan differed from those for cohorts of ai-TTP patients in Europe and North America- raising concern that TTP findings vary by region of the world. (PLOS One 2011) We now on report clinical and laboratory characteristics of a cohort of TTP patients from Japan with tc-TTP, and compare these findings to three cohorts of tc-TTP in the United States and one cohort of ai-TTP patients from Japan.

Methods:
We queried a database of thrombotic microangiopathy patients identified from a national TTP referral laboratory in Japan of cases identified between 1998 and 2008.
Severe ADAMTS13 deficiency was characterized by activity levels < 5%. All tc-TTP patients and 186 of 911 ai-TTP patients in the database had severe ADAMTS13 deficiency and first onset of TTP. Comparisons were made to tc-TTP patients reported previously from the United States.

Results:
Characteristics of ai- TTP with severe ADAMTS13 deficiency in Japan and tc-TTP in Japan and US

Conclusions:
These data from Japan validate insights about tc-TTP initially proposed in 1998, 1999, and 2000 in the United States. Ticlopidine is a likely cause of TTP, the mechanism is via a cross-reactive antibody to ADAMTS13:AC resulting in formation of an ADAMTS13:INH, and therapeutic plasma exchange is necessary for treatment.

Disclosures:
Ortel: Eisai: Research Funding; Glaxo SmithKline: Research Funding; Pfizer: Research Funding; Instrumentation Laboratory, Inc: Consultancy, Research Funding; Boehringer Ingelheim: Consultancy. Fujimura:Baxter BioScience: Membership on an entity's Board of Directors or advisory committees; Alexion Pharma: Membership on an entity's Board of Directors or advisory committees.