bluuebunny/crossref_metadata_2025 huggingface dataset:
Allogeneic Stem Cell Transplantation in a Pediatric Patient with Whim Syndrome
Authors: Bhar Saleh , Yassine Khaled , Martinez Caridad , Sasa Ghadir S. , Naik Swati , Mahoney Donald , Allen Carl , Ahmed Nabil , Hegde Meenakshi G. , Heslop Helen E. , Gottschalk Stephen , Krance Robert A. , Leung Kathryn S.
Published: October 2019

WHIM syndrome (warts, hypogammaglobulinemia, infections, and myelokathexis) is a rare autosomal dominant immunodeficiency disorder that is caused by a gain in function in cysteine-X-cysteine chemokine receptor 4 (CXCR4) gene. Affected individuals have recurrent infections of the respiratory tract and soft tissues, and marked susceptibility to warts caused by human papilloma viruses (HPV). Patients have an increased risk of malignancy (lymphoma) and HPV-associated cancers. The optimal therapy for WHIM syndrome has not been defined and treatment has been with supportive care using intravenous immunoglobulin (IVIG) and granulocyte colony stimulating factor (G-CSF). New CXCR4 antagonist therapies are still in either phase I trials (plerixafor) or considered experimental (Chlacone-4).

A successful umbilical cord blood transplant has been reported by Kriven et al. Here we describe a successful matched unrelated allogeneic stem cell transplant (SCT) in a girl with WHIM syndrome caused by a known mutation in the CXCR4 gene.

This patient was diagnosed at birth with familial congenital neutropenia as findings were similar to those for the patient's mother and maternal grandmother. A complete blood count showed pancytopenia (WBC= 1.03 x103/µL, hemoglobin= 9.2 g/dL, platelet count= 74,000/µL, ANC= 70). Despite G-CSF and IVIG therapy, the patient had recurrent infections with sinusitis and pneumonia, along with progressive organomegaly with progressive pancytopenia.

At the age of 4, the patient underwent matched unrelated SCT with a fully ablative regimen [busulfan 0.8 mg/kg/dose for 16 doses (days -9, -8, -7, and -6), cyclophosphamide 50 mg/kg/dose for 4 doses (days -5, -4, -3, and -2) and alemtuzumab 5 mg/day (weight-based dosage) for 3 doses (days -5, -4, and -3)]. Tacrolimus and mini methotrexate (on days +1, +3, +6 and +11) were given for GVHD prophylaxis. Neutrophil and platelet engraftment occurred on days + 21 and + 45, respectively. The patient is 100% donor chimeric. Post-transplant course has been complicated by grade II skin GVHD treated successfully with oral and topical steroids. The patient also developed adenovirus, BK virus and HHV-6 viral reactivations but without disease. The patient is now approximately 2 years post SCT with durable engraftment, normal humoral immune reconstitution and no chronic GVHD.

Thus, stem cell transplant following myeloablative conditioning can be accomplished for patients with WHIM syndrome. Furthermore, transplantation performed at the patient's young age likely prevented complications of recurrent infections and warts.

Disclosures

Allen: NovImmune: Consultancy, Other: unpaid; Roche: Consultancy, Other: unpaid. Heslop:Cell Medica: Other: Licensing Agreement; Celgene: Other: Collaborative research agreement.
Validation of the EBMT Risk Score for Patients with Hematologic Malignancies Receiving Allogeneic Hematopoietic Stem Cell Transplant in a Transplant Center in Colombia over 20 Years
Authors: Abello Virginia , Rosales Carmen , Rosales Manuel , Figueroa Javier , Cordoba Iris , Borda Molina Andres Armando , Pedraza Enrique , Esguerra Herman , Villamizar Liceth
Published: October 2019

INTRODUCCION

EMBT the risk score has been validated in several studies in different types of diseases and modalities of transplantation. The conditions of the patients and the resources available in Latin America are different from those of European centers, so we consider important to validate this scale in our own patients.

METHODS

EBMT risk scale was validated in 965 of 1176 (750 autologous, allogeneic 426) transplanted from 1993 to 2014; that had all the information available and were not lost to follow up. Kaplan-Meier survival curves and log-rank test (p <0.05) were used to estimate the one (OS1) and three (OS3) probabilities of overall survival according to risk groups.

RESULTS

The mean age was 39.8 (SD 15.5). The median follow-up was 363 days (range: 179-1096) for the whole group. Most frequent diagnoses were Non-hodgkins lymphoma (314: 26.7%) and multiple myeloma (262: 22.22%). 96.3% transplants were performed using peripheral blood stem cells. Most donors were identical siblings; only 19.5% (n = 79) were transplanted before 2004.

81.9% of transplanted patients had 2-4 points on EBMT risk score. Upon analysis it became clear that at 1 and 3 years, two groups were defined: Low (0-3 points) and high (4-7), with a significant difference in overall survival for AML (1 year: p = <0.00; 3 years: p = <0.00) and ALL (1 year: p = 0.04; 3 years: p = 0.01). In NHL 4 risk groups remain significantly different in regards to 1 and 3 years overall survival (1 year: p = 0.04; 3 years: p = 0.02). In patients with diagnosis of MDS EBMT was predictive of survival only significant at one year (p = 0.01).

The EBMT score did to delineate risk groups patients with MM, LH, ASMO, or CML in this group.

CONCLUSION

EBMT score was validated in patients with hematologic malignancies transplanted in a center in Colombia, to our knowledge this is the first validation of this risk score in Latin America.

Disclosures

No relevant conflicts of interest to declare.
PLGA-PLL-Peg-Tf-Based Targeted Nanoparticles Drug Delivery System Enhance Antitumor Efficacy Via Intrinsic Apoptosis Pathway
Authors: Bao Wen , Liu Ran , Chen Baoan , Wang Fei , Zhang Haijun , Xia Guohua , Wu Xue , Zhao Kun , Li Xiaoyu
Published: October 2019

Chemotherapy offers a systemic cancer treatment; however, it is limited in clinical administration due to its serious side effects. In cancer medicine, the use of nanoparticles (NPs) drug delivery system (DDS) can sustainedly release anticancer drug at the specific site and reduce the incidence of toxicity in normal tissues. In the present study, we aimed to evaluate the benefit of a novel chemotherapeutic DDS and its underlying mechanisms. Daunorubicin (DNR) was loaded into poly (lactic-co-glycolic acid) (PLGA)-poly-L-lysine (PLL)-polyethylene glycol (PEG)-transferrin (Tf) NPs to construct DNR-PLGA-PLL-PEG-Tf-NPs (DNR-loaded NPs) as a DDS. After incubating with PLGA-PLL-PEG-Tf-NPs, DNR, and DNR-loaded NPs, the leukemia K562 cells were collected and the intracellular concentration of DNR was detected by flow cytometry, respectively. Furthermore, the effect of drugs on the growth of tumors in K562 xenografts was observed and the relevant toxicity of therapeutic drugs on organs was investigated in vivo. Meanwhile, cell apoptosis in the excised xenografts was measured by transferase-mediated dUTP nick-end labeling assay, and the expression of apoptosis-related proteins, including Bcl-2, Bax, Caspase-9, Caspase-3, and cleaved-PARP, was determined by Western blotting analysis. Results showed that DNR-loaded NPs increased intracellular concentration of DNR in K562 cells in vitro and induced a remarkable improvement in anticancer activity in the xenografts in vivo. The expression of Bcl-2 protein was downregulated and that of Bax, Caspase-9, Caspase-3, and cleaved-PARP proteins were obviously upregulated in the DNR-loaded NPs group than that in other ones. Interestingly, pathological assessment showed no apparent damage to the main organs. In summary, the results obtained from this study showed that the novel NPs DDS could improve the efficacy of DNR in the treatment of leukemia and induce apoptosis via intrinsic pathway. Thus, it can be inferred that the new drug delivery may be a useful clinical tool.

Disclosures

No relevant conflicts of interest to declare.
Overuse of DVT Prophylaxis in Medical Inpatients
Authors: Deng Jing , Thomas Lisa , Li Huijing , Varughesekutty Elvin , Shi Qi , Sambharia Meenakshi , Musto Kevin , Petal Gaurav , Gordon Erin , Ruparella Sudeep , Bansal Rajiv
Published: October 2019

Introduction: Unfractionated heparin (UFH), or low-molecular-weight heparin (LMWH), is commonly used with mechanical prophylaxis as an anticoagulant to reduce the risk for venous thromboembolism (VTE). However, overuse of these prophylaxes can increase the risk of bleeding, heparin-induced thrombocytopenia (HIT) and associated medical cost.

PURPOSE: The aim of this study is to determine the incidence of DVT prophylaxis among hospitalized nonsurgical patients in a community medical center. To evaluate the use of the prophylaxes as described above, the investigators collected data on medical inpatients and addressed how to avoid overuse.

Method: A retrospective inpatient chart review of 100 general internal medicine patients analyzed data using Padua Prediction Score as the risk estimate for deep venous thrombosis (DVT). High risk for VTE was defined by a cumulative score >=4 and low risk was a score <4. Only patients at increased risk for DVT but not at high risk for bleeding qualified for heparin treatment.

Results: A total of 100 patients were surveyed. 54/100 (54%) patients had low risk of DVT with score < 4, and of those 29/54 (53.7%) patients received DVT prophylaxis with SCDs and/or heparin, and 17/54 (31.5%) patients were treated with heparin. All 46 patients with score >= 4 were treated with DVT prophylaxis of which 10 patients were only treated with heparin and 36 patients were given both mechanical and chemical prophylaxis. Collectively, 53.7% of the patients received treatment with DVT prophylaxis (p < 0.001, Chi-Square test).

Discussion:

In hospital settings, physicians want to avoid DVT or PE so they tend to consider patients as being at moderate risk for DVT without using any method of DVT risk assessment. This leads to unnecessary overuse of DVT prophylaxis on patients and may increase the risk of bleeding and injury.

Conclusion:

Our data suggests that there DVT prophylaxis including UFH and LMWH was over prescribed among patients with who had marginal risk for DVT in hospitalized nonsurgical patients in a community medical center.

Clinical implications:

To avoid the overuse of DVT prophylaxis, physicians need to follow guidelines. Education and inclusion of the guidelines in EHRs of information on VTE risk assessment for hospitalized medical patients upon admission may reduce unneeded DVT prophylaxis and the risk of bleeding and costs associated with additional care needs.

Disclosures

No relevant conflicts of interest to declare.
All-Cause Health Care Resource Utilization in Individuals with Sickle Cell Disease
Authors: Rajpura Jigar , Thomas Joseph
Published: October 2019

Introduction

Clinical manifestations of Sickle Cell Disease (SCD) range from frequent fatigue and anemia to severe complications involving multiple organs. We estimated all cause health care resource utilization in individuals with SCD as compared to individuals without SCD.

Methods

Data from the Truven multi-state Medicaid claims database were used for all analyses. Sample inclusion criteria was being enrolled in covered health plan from January 1, 2012 through December 31, 2012. A cohort of individuals with SCD was identified based on having at least one inpatient or two or more outpatient claims with ICD-9-CM codes for sickle-cell thalassemia without crisis (282.41), sickle-cell thalassemia with crisis (282.42), Sickle-cell disease, unspecified (282.60), Sickle-cell-S disease without crisis (282.61), Sickle-Cell-S disease with crisis (282.62), Sickle-cell-C disease without crisis (282.63), Sickle-cell-C disease with crisis (282.64), other sickle-cell disease without crisis (282.68), or other sickle-cell disease with crisis (282.69). From the continuously enrolled individuals, a cohort of individuals without SCD was identified by matching individuals with SCD one-to-one on age, gender, and ethnicity. Means and 95 percent confidence intervals were calculated for, number of hospitalizations, hospital days, long term care visits, long term care days, emergency room visits, and outpatient visits. Wilcoxon Mann-Whitney test was employed to assess differences in health care resource utilizations in individuals with and without SCD.

Results

Among 5,136,748 individuals covered in the study period, 8,652 individuals with SCD were identified and matched to 8,652 individuals without SCD. Majorities of the study sample were black (74%), female (54%), and under 24 years old (64%). Mean annual hospitalizations among individuals with SCD were 1.39 (95 percent C.I.: 1.3 to 1.4, <0.001) as compared to 0.10 (95 percent C.I.: 0.09 to 0.1, p<0.001) hospitalizations in persons without SCD. Mean annual outpatient visits in individuals with SCD were 24.7 (95 percent C.I.: 23.9 to 25.5, p<0.001) as compared to 14.18 (95 percent C.I.: 13.4 to 14.9, p<0.001) outpatient visits in persons without SCD, and, mean annual emergency room visits in individuals with SCD were 3.71 (95 percent C.I.: 3.5 to 3.9, p<0.001) as compared to 0.89 (95 percent C.I.: 0.8 to 0.9, p<0.001) emergency room visits in persons without SCD.

Conclusions

SCD was associated with higher annual hospitalizations, hospital days, outpatient visits and emergency room visits as compared to individuals without SCD.

Disclosures

Rajpura: Pfizer Inc.: Research Funding. Thomas:Pfizer Inc.: Research Funding.
Acute Myeloid Leukemia (AML): A Retrospective Claims Analysis of Resource Utilization and Expenditures
Authors: Irish William D , Ryan Michael , Gache Larry , Gunnarsson Candace , Bell Timothy , Shapiro Mark
Published: October 2019

Motivation/Objectives: The primary objective of this study was to estimate resource utilization and expenditures for de novo (dn) AML patients in a real world claims database.

Sponsorship Statement: This study was sponsored by Pfizer, Inc.

Methods: All AML patients with an ICD-9 diagnosis code of 205.00 (dn) and a record of a hospitalization within 14 days after their initial diagnosis between 1/1/2009 - 1/31/2015 were identified in the MarketScan Commercial, Medicaid, and Medicare supplemental databases. Patients also had to have a minimum of two instances of the AML diagnosis code and ≥6 mos of enrollment prior to their first AML diagnosis. Patient demographics, Charlson Comorbidity Index from the National Cancer Institute (CCI NCI), risk factors for AML, such as history of smoking and blood disorders, and key comorbid conditions were recorded. Age at initial diagnosis was grouped as follows: <18, 18-<50, 50-70 and >70 years. Healthcare utilization and expenditures (in 2014 dollars) were aggregated for dn patients from first line induction to remission. For the subset of patients that had a record of relapse and remission following induction, their healthcare utilization and expenditures were aggregated from the time of relapse to their second remission.

Results: Of the 1,671 patients meeting the inclusion criteria the mean (SD) age was 58.3 (16.7). Age at initial diagnosis by group was as follows: less than 18 years, 0.4%; 18 to 50 years, 26.5%; 50 to 70 years, 49.7%; and greater than 70 years, 23.5%. Male patients made up 51% of the cohort and mean (SD) CCI NCI score for all patients was 1.1 (1.6). Over 90% of patients had at least one risk factor for AML, with 88% of patients having a history of blood disorders. Mean healthcare expenditures for patients who achieved remission (n=703) were $208,431 (SD $153,144). A subset of patients (n=145) had a record of a second treatment period defined as days from their first record of relapse to their second remission. During this second treatment period, mean healthcare expenditures were $127,953 (SD $175,020); 61.4% were admitted to the hospital for an average of 16.8 hospital days; and 22.8% had at least one ER visit.

Conclusions: Treating AML patients poses a significant healthcare burden, both during de novo and relapse. With people living longer, the number of cases of AML are expected to increase in the future.

Disclosures

Irish: Pfizer Inc: Consultancy; Alexion: Consultancy; BMS: Consultancy; Novartis: Consultancy; Sanofi: Consultancy; Astellas: Consultancy. Ryan:Pfizer Inc: Consultancy. Gache:Pfizer Inc: Consultancy. Gunnarsson:Pfizer Inc: Consultancy. Bell:Pfizer Inc: Employment. Shapiro:Pfizer Inc: Employment.
Neutrophil DREAM Is a Novel Regulator for Beta2 Integrin Function through NF-Kappab Signaling and Modulates Neutrophil Recruitment during Vascular Inflammation
Authors: Barazia Andrew , Li Jing , Kim Kyungho , Tiruppathi Chinnaswamy , Cho Jaehyung
Published: October 2019

The interaction between neutrophils and activated endothelial cells (ECs) is critical for the pathogenesis of vascular inflammation. However, it remains poorly understood how the cell-cell interactions are regulated under inflammatory conditions. Using intravital microscopy in mice lacking DREAM (downstream regulatory element antagonist modulator), a member of the neuronal Ca2+ sensors and a transcriptional repressor, we have found that DREAM plays an important role in neutrophil rolling and adhesion to the TNF-α-inflamed cremaster muscle venules. Studies with DREAM bone marrow chimeras revealed that both hematopoietic and EC DREAM are important for neutrophil recruitment. We found that neutrophils lacking DREAM exhibit reduced αMβ2 surface expression and decrease fibrinogen binding following stimulation with TNF-α, but not fMLF, implying the role for neutrophil DREAM in regulating β2 integrin function through a specific signaling pathway. Since recent studies demonstrated the important role of endothelial cell DREAM in NF-κB signaling, we further examined whether neutrophil DREAM regulates NF-κB signaling. Indeed, the protein expression of A20 (an inhibitor of NF-κB signaling) and p65 (a key subunit of the NF-κB complex) was significantly up- and down-regulated, respectively, in DREAM-deficient neutrophils, compared to WT neutrophils. Moreover, DREAM deletion impaired the phosphorylation of IKKa/β following TNF-a-stimulation, suggesting the role of neutrophil DREAM in NF-κB signaling. Consistently, we found that the transcription of the NF-κB target genes, such as IL-1β, TNF-α, and IL-6, was inhibited by DREAM deletion. Taken together, our results provide evidence that neutrophil DREAM is a novel regulator for β2 integrin function through NF-κB signaling and could be a therapeutic target for treatment of inflammatory disease.

Disclosures

No relevant conflicts of interest to declare.
Preclinical Evaluation of RA101495, a Potent Cyclic Peptide Inhibitor of C5 for the Treatment of Paroxysmal Nocturnal Hemoglobinuria
Authors: Ricardo Alonso , Arata Michelle , DeMarco Steven , Dhamnaskar Ketki , Hammer Robert , Fridkis-Hareli Masha , Rajagopal Vaishnavi , Seyb Kathleen , Tang Guo-Qing , Tobe Sylvia , Treco Douglas
Published: October 2019

Regulation of the terminal phase of the complement component pathway is a clinically validated approach for the therapeutic treatment of complement disorders. Inhibition of complement activation at the C5 level with the monoclonal antibody eculizumab has successfully been used for the treatment of rare disorders such as PNH and aHUS. However, even in these settings there remains a continued unmet need primarily due to need for intravenous administration, lack of activity in patients with C5 mutations and lack of universal access.

Ra Pharmaceuticals has developed a macrocyclic synthetic peptide, RA101495, which binds complement C5 with subnanomolar affinity and allosterically inhibits its cleavage into C5a and C5b upon activation of the classical, alternative or lectin pathways. In vitro studies also demonstrated that RA101495 is capable of preventing MAC assembly after thrombin mediated complement activation and is a potent disruptor of the interaction in between C5b and C6.

Inhibition of complement activity was evaluated in cynomolgus monkeys following single- and multi-dose subcutaneous (SC) administration. RA101495 exhibited high SC bioavailability and low, single doses fully inhibited complement-mediated hemolytic activity (>95%). Repeat dosing was well tolerated in monkeys and rats at high multiples of the projected human therapeutic dose and resulted in sustained and predictable inhibition of complement activity.

RA101495 fully inhibited the hemolysis of erythrocytes from PNH patients after activation of the alternative pathway. The synthetic peptide offers a novel therapeutic approach for inhibiting C5 for the treatment of disorders caused by or associated with complement dysregulation. As a product designed for convenient self-administration, RA101495 should provide an attractive option over monoclonal antibody therapy for patients with PNH and aHUS, including those with C5 polymorphisms and other complement disorders, especially those associated with hypercoagulable states.

Disclosures

Ricardo: Ra Pharmaceuticals: Employment. Arata:Ra Pharmaceuticals: Employment. DeMarco:Ra Pharmaceuticals: Employment. Dhamnaskar:Ra Pharmaceuticals: Employment. Hammer:Ra Pharmaceuticals: Employment. Fridkis-Hareli:Ra Pharmaceuticals: Consultancy. Rajagopal:Ra Pharmaceuticals: Employment. Seyb:Ra Pharmaceuticals: Employment. Tang:Ra Pharmaceuticals: Employment. Tobe:Ra Pharmaceuticals: Employment. Treco:Ra Pharmaceuticals: Employment.
Association Between Serum Ferritin and Liver Iron Concentration with Cardiac Iron in Pediatric Thalassemia Major Patients
Authors: Pepe Alessia , Meloni Antonella , Casale Maddalena , Neri Maria Giovanna , Bitti Pier Paolo , Macchi Silvia , Giugno Giovanni Roberto , De Franceschi Lucia , Missere Massimiliano , Toia Patrizia , Positano Vincenzo , Filosa Aldo
Published: October 2019

Introduction: Recently, the ability of LIC (liver iron concentration) and serum ferritin in predicting myocardial iron overload (MIO) has been challenged by magnetic Resonance Imaging (MRI) monitoring which demonstrated no or weak correlation between serum ferritin or LIC and MIO. Anyway, the role of this traditional markers could result particularly useful in pediatric population, where MRI assessment is difficult to carry out, because of early age, scarce collaboration or limited availability. So, we derived objective thresholds for these markers for predicting cardiac T2*<20 ms in pediatric patients.

Methods: From the 2171 patients with hemoglobinopathies enrolled in the MIOT (Myocardial Iron Overload in Thalassemia) network, we retrospectively selected 107 paediatric patients with thalassemia major (TM) (61 boys, median age 14.4 years). MIO was assessed using a multislice multiecho T2* approach. Hepatic T2* values were assessed in a homogeneous tissue area and converted into LIC.

Results: Twenty-three patients (21.5%) showed an abnormal global heart T2* value and none of them was under 7.9 years of age.

Serum ferritin was negatively correlated with global heart T2* values (r=-0.425; P<0.0001). Using ROC curve analysis, a serum ferritin of 2000 ng/ml was found to be the best threshold for discriminating the presence of cardiac iron with an area under the curve (AUC) of 0.733 (P=0.001) (Figure 1A) (Sensitivity= 0.73 and Specificity=0.65). Odds ratio (OR) for global heart T2* values<20 ms was 4.9 (1.7-13.8 95%CI; P=0.003) for serum ferritin levels ≥2000 ng/ml.

There was a significant negative correlation between global heart and MRI LIC values (P=-0.436; P<0.0001). Using ROC curve analysis, a LIC≥14 mg/g/dw was found to be the best threshold for discriminating the presence of MIO in children with an AUC of 0.817 (P<0.0001) (Figure 1B) (Sensitivity= 0.74 and Specificity=0.85 ). OR for abnormal global heart T2* values was 30.08 (3.58-252.68 95%CI; P=0.002) for patient with MRI LIC≥14 mg/g/dw versus patients with normal MRI LIC.

Conclusion: A weak connection between serum ferritin levels or hepatic iron and cardiac iron was demonstrated in our pediatric population. Anyway, MRI LIC≥14 mg/g/dw and serum ferritin levels≥2000 ng/ml were found to be significant risk factors for a global heart T2* value <20 ms in TM children.

Figure 1. Figure 1.

Disclosures

Pepe: Novartis: Speakers Bureau; ApoPharma Inc: Speakers Bureau; Chiesi: Speakers Bureau.
Heme Concentration As a Biomarker of Sickle Cell Disease Severity: Its Role in Steady-State and in Crisis Patients
Authors: Carvalho Magda Oliveira Seixas , Rocha Larissa Carneiro , Reis João Henrique Oliveira , Santos Théo de Araújo , do Nascimento Valma Maria Lopes , Carvalho Mauricio Batista , Luz Nívea Farias , Borges Valeria de Matos , Goncalves Marilda Souza
Published: October 2019

Background: Sickle cell disease (SCD) is a heredity group of anemia characterized by hemolysis, chronic inflammation, and vaso-occlusive/painful crisis. The heme is a product of erythrocytes' lyses and is increased in hemolytic diseases.

Objectives: To investigate associations between hematological/biochemistry biomarkers and total plasma heme levels between SCD patients groups (in crisis and in steady-state) and healthy controls. To identify molecules related to hemolysis, inflammation, hepatic dysfunction, renal and lipid metabolism.

Methods: We evaluated a total of 125 SCD steady-state patients, 22 SCD in crisis patients, and 32 healthy individuals age- and sex-matched with patients groups. Hematological analyses were performed by automatic cell counter, and hemoglobin profile by HPLC. Biochemistry analyses of inflammatory and infection markers, as well as lipid, hepatic, and kidney metabolism markers were investigated by immunochemistry assays. Plasma concentration of total free heme was measured by QuantiChrom Heme Assay Kit.

Results: SCD patients groups (steady state and crisis) had higher heme concentration when compared to healthy individuals (p < 0.0001). However, significant difference of heme level was not finding in the comparison between SCD in steady state and SCD crisis patients groups. Biomarkers analyses of steady-state SCD patients showed negative correlation between heme levels and: red blood cell (r = -0.36, p<0.0001); hematocrit (r = -0.38, p <0.0001); hemoglobin (r = -0.34, p <0.0001); and HDL-C (r = -0.42, p <0.0001). Heme level showed positive correlation with: platelets (r = 0.35, p <0.0001); lactic dehidrogenase (r = 0.40, p <0.0001); reticulocytes count (r = 0.19, p =0.04); monocytes count (r = 0.36, p <0.0001); HbS concentration (r = 0.54, p <0.0001); total proteins (r = 0.22, p =0.01); AST (r = 0.41, p <0.0001); ALT (r = 0.18, p= 0.04); serum iron (r =0.21, p =0.03); total cholesterol (r = 0.23, p =0.01); LDL-C (r = 0.22, p= 0.02); VLDL-C (r = 0.65, p <0.0001); and triglycerides (r = 0.63, p <0.0001). In steady state SCD patients there was no difference of clinical manifestations history and heme levels.

Conclusions: The finding of similar heme concentration between steady state and crisis SCD patients may be explained by the hyperhemolysis phenomenon, showing that even in steady-state, these patients continue to have hemolysis and generate heme and reactive oxygen species. It was also shown that high concentration of free heme increases hemolytic and inflammatory biomarkers, such as LDH, bilirubin's, reticulocytes count, and lipids, contributing to a severe clinical modulation of SCD.

Disclosures

No relevant conflicts of interest to declare.
Genetics in Inherited Bone Marrow Failure Disorders
Authors: Keel Sioban
Published: October 2019

The classical Inherited Bone Marrow Failure Syndromes (IBMFS) such as Fanconi anemia, Dyskeratosis Congenita, Shwachman-Diamond syndrome, and Diamond-Blackfan anemia are a heterogeneous group of disorders, all of which are characterized by impaired hematopoiesis, varying degrees of peripheral cytopenias and marrow hypoplasia and dysplasia. Many of these are associated with an increased risk of clonal dominance and evolution to myelodyplastic syndrome (MDS) and acute myeloid leukemia (AML). For the purposes of this talk, the familial MDS and acute leukemia predisposition syndromes are also included in the broad term IBMFS. The genes responsible for a subset of IBMFS have been identified and will be reviewed. However, the causative mutations in many patients presenting with seemingly inherited marrow failure remain unknown. Gene discovery in IBMFS has been difficult in large part due to the phenotypic heterogeneity of these syndromes. Some patients with IBMFS display a distinct clinical phenotype with associated syndromic abnormalities, others are variable and overlap with one another or with acquired MDS or idiopathic acquired aplastic anemia, and additional cases are more obscure and have evaded classification altogether. Accurate diagnosis of IBMFS inform patient care as it allows appropriate screening of siblings to avoid choosing an affected donor if marrow transplant is indicated and the selection of an appropriate transplant conditioning regiment to avoid undue toxicity. Additionally, accurate diagnosis allows appropriate medical monitoring and early intervention to successfully treat disease-specific non-hematologic medical complications. The application of next generation sequencing approaches for comprehensive genetic screening of IBMFS, including these cryptic or atypical presentations will be reviewed. In addition to providing accurate diagnoses in a subset of patients, genetic characterization in small family kindreds or even in single individuals presents unique opportunities to discover new genes and pathways contributing to dysfunctional hematopoiesis and clonal progression. The frequency of inherited mutations in known IBMFS genes among seemingly idiopathic acquired aplastic anemia patients or pediatric and younger adults with MDS referred for hematopoietic stem cell transplant will be reviewed. Future genetic studies are needed to characterize the secondary genetic events that lead to disease progression in IBMFS.

Disclosures

No relevant conflicts of interest to declare.
Platelet Activation Gradients During Thrombus Formation
Authors: Stalker Timothy J.
Published: October 2019

The hemostatic response requires the tightly regulated interaction of the coagulation system, platelets, other blood cells and components of the vessel wall at a site of vascular injury. The dysregulation of this response may result in excessive bleeding if the response is impaired, and pathologic thrombosis with vessel occlusion and tissue ischemia if the response is overly robust. Extensive studies over the past decades have sought to unravel the regulatory mechanisms that coordinate the multiple biochemical and cellular responses in time and space to ensure that an optimal response to vascular damage is achieved. We and others have observed that platelet activation at a site of injury in vivo is heterogeneous, with a gradient of platelet activation extending from the site of injury. Platelets immediately adjacent to the injured vessel wall are densely packed and fully activated forming a stably adherent core region. This stable core is overlaid by a shell of less activated platelets that are more loosely packed. Genetic and pharmacologic studies have shown that the formation of these regions is dependent on partially overlapping gradients of distinct platelet agonists, with ADP serving as a mediator of platelet recruitment and retention in the shell region, and thrombin necessary for full platelet activation in the core region. The distribution of platelet agonists and other plasma solutes in time and space is in turn determined in part by their transport in the plasma microenvironments that evolve as platelets accumulate. Platelet mass consolidation and the subsequent narrowing of the gaps between platelets are important mechanisms by which plasma solutes are retained within the platelet mass to promote platelet activation. Consolidation also regulates the escape of plasma and platelet-derived bioactive molecules into the extravascular space. These studies and others examining how cellular, biochemical and physical factors are integrated to shape the optimal response to vascular injury in vivo will be discussed.

Disclosures

No relevant conflicts of interest to declare.
Megakaryocytic Fate Specification and Maturation
Authors: Krause Diane S
Published: October 2019

Megakaryocyte maturation and polyploidization are essential for effective platelet formation. In a tightly controlled process, bipotent megakaryocyte-erythroid progenitors (MEP) differentiate into diploid megakaryoblasts; undergo a progressive increase in ploidy, resulting in very large cells with multilobated polyploid nuclei; and undergo extensive cytoplasmic maturation in preparation for proplatelet release. Recent studies have begun to unravel the complex genetic and epigenetic changes that promote megakaryocyte specification from hematopoietic stem and progenitor cells, and that control subsequent megakaryocyte polyploidization and maturation. The transcriptional regulatory network underlying specification from MEP is emerging, with data revealing that many of the same factors that regulate specification also play critical roles in the final stages of megakaryocyte maturation, whereas other factors are critical for specification, but must be then inactivated in order for cell maturation to occur. Megakaryopoiesis is disrupted in several malignant and non-malignant disorders that result in significant morbidity and mortality. Mutations are inherited or acquired, and affect megakaryocyte specification, maturation and subsequent platelet formation, or both. Novel, findings will be covered in the context of normal transcriptional regulation, potential mechanisms of megakaryocyte dysplasia in MDS, and transformation to acute megakaryoblastic leukemia. These studies build the basis for our understanding of inherited and acquired megakaryocytic abnormalities and thrombocytopenias.

Disclosures

No relevant conflicts of interest to declare.
Impact of Genetic Predispositions, Diet, and Environment on Storage of Red Blood Cells
Authors: Spitalnik Steven L
Published: October 2019

It remains controversial whether or not transfusions of human red blood cells (RBCs), which have been refrigerator-stored for extended time intervals, induce or exacerbate clinically-relevant adverse effects in recipients. The described effects include infection, inflammation, renal dysfunction, thrombosis, and even death. It is also controversial whether such effects are seen in particular patient populations predisposed to these types of complications, or whether they are universal. To this end, multiple bench research studies, clinical/translational studies, and prospective randomized controlled trials are currently investigating these issues. What is not controversial is that refrigerated storage produces the "RBC storage lesion" and that this worsens in proportion to increasing storage time, such that, at the FDA-mandated 42-day outdate, on average, only 75% of transfused donor RBCs are still circulating in the recipient at 24-hours post-transfusion. It is also not controversial that RBCs obtained from some healthy volunteer donors do not store well and, at outdate, have a 24-hour post-transfusion recovery (PTR) of significantly less than 75% (i.e., "poor storers"). Analogously, RBCs from some donors store extremely well and may exhibit virtually 100% 24-hour PTR at outdate (i.e., "super storers"). Understanding the underlying mechanisms for these phenomena would allow implementation of various approaches to improve the blood supply, with an ultimate goal of virtually 100% 24-hour PTR and normal long-term circulatory lifespan of transfused RBCs. This goal is especially relevant in the chronic transfusion setting (e.g., patients with sickle cell anemia or beta-thalassemia). Similar observations have been made about hemolysis ex vivo (i.e., "in the bag") during refrigerated storage, which influences the amount of free hemoglobin infused during the transfusion procedure. There is also evidence that these RBC storage characteristics are stable in "poor" and "super" donors, suggesting that genetic, dietary, and/or environmental factors are involved. Indeed, using inbred strains of mice, there is clear evidence that genetic and dietary factors can significantly influence donor RBC storage quality, when measured as 24-hour PTR and/or ex vivo hemolysis. In addition, human genetic polymorphisms, particularly in racial/ethnic groups enriched for malaria-induced traits, result in abnormal expression or abnormal function of various RBC proteins, including hemoglobin and cytosolic enzymes, such as glucose-6-phosphate dehydrogenase. There is increasing evidence that these polymorphisms can influence the ability of human RBCs to tolerate standard conditions of refrigerated storage. Harnessing this information will result in new methods for improving the quality of the blood supply and, consequently, improving patient responses to transfusion therapy.

Disclosures

No relevant conflicts of interest to declare.
Re-educating the Tumor Microenvironment in the Clinic
Authors: Ansell Stephen
Published: October 2019

The tumor microenvironment plays a central role in lymphoproliferative disorders and constitution of the microenvironment is associated with patient outcome. Although malignant lymphocytes predominate, cells other than tumor cells are commonly present in malignant lymph nodes. These cells include T lymphocytes, NK cells, dendritic cells and monocytes that seem to be more than simple residual elements from the normal lymph node structure. It is thought that these infiltrating immune cells are part of an antitumor immune response, yet they appear unable to eradicate the malignant clone.

Previous studies have shown however that multiple factors present in the tumor microenvironment oppose an effective antitumor immune response. Cells with suppressive function, including T regulatory cells, myeloid derived suppressor cells and suppressive monocytes, are abundant in lymphoma tissue. Suppressive cytokines such as TGFβ and IL-10 are highly expressed in tumors. Furthermore, intratumoral T-cell exhibit an exhausted phenotype with limited proliferation, cytokine production or cytolytic function. Recent therapeutic approaches have focused on overcoming T-cell suppression by activating T-cells or blocking inhibitory signals, thereby re-educating the suppressive tumor microenvironment.

Clinical trial results with PD-1 and CTLA-4 directed antibodies in both non-Hodgkin lymphoma and Hodgkin lymphoma have been very promising. Overall response rates particularly in Hodgkin lymphoma patients treated with anti-PD-1 antibodies have been remarkable, although complete responses have been uncommon. Current studies are in progress to confirm the initial results, and further trials will assess the efficacy of immune checkpoint blockade in combination with standard therapies.

Disclosures

Ansell: Bristol-Myers Squibb: Research Funding; Celldex: Research Funding.
Mechanisms Governing Disruption of Telomere Maintenance in Dyskeratosis Congenita
Authors: Artandi Steven
Published: October 2019

Dyskeratosis congenita (DC) is a bone marrow failure syndrome characterized by widespread defects in diverse tissues and a strong predisposition to cancer. DC is caused by germline mutations in genes controlling maintenance of telomeres, nucleoprotein caps that protect chromosome ends. DC is part of a larger collection of telomere disorders whose manifestations include pulmonary fibrosis, liver cirrhosis and defects in many other tissues. Mutations in components of the telomerase enzyme comprise a large share of cases, including in TERT, TERC, dyskerin, TCAB1, NOP10 and NHP2. These mutations compromise telomerase function leading to telomere shortening, which in turn impairs stem cell function. The telomerase holoenzyme operates according to a complex cycle of assembly, nuclear trafficking, recruitment to telomeres and catalytic action to elongate telomeres. In patients with telomere disease states, each of these steps can be impaired leading to a common set of disease phenotypes. We previously created patient-derived iPS cells from patients with mutations in TERT, dyskerin or TCAB1 and analyzed these cells to understand the biochemical defects in the telomerase pathway. Molecular defects in these patients operate according to diverse mechanisms including: reduced catalytic function, impaired telomerase assembly, mislocalization of the enzyme to nucleoli and defective recruitment to telomeres. The development of therapeutics to treat these disease states will require approaches targeted to the underlying molecular defects in each form of the disease.

Disclosures

No relevant conflicts of interest to declare.
Extrahematopoietic Manifestations of Telomere Syndromes
Authors: Armanios Mary
Published: October 2019

Abnormally short telomeres give rise to a group of premature aging, cancer-prone disorders known as the telomere syndromes. They are caused by germline mutations in telomerase and telomere genes. Although bone marrow failure was one of the first complications to be described in dyskeratosis congenita, there is increasing appreciation that this classic presentation is rare. Extra-hematopoietic telomere-mediated disease is frequently the first and predominant presentation in adults and leads to significant morbidity and mortality in patients with bone marrow failure (BMF), especially after bone marrow transplantation. It shows stereotypic manifestations that are age-dependent. Enterocolitis can precede the onset of BMF in infants with Hoyeraal-Hreidarsson syndrome, and it represents an intestinal epithelial defect that progresses in the setting of immunodeficiency. In adults with familial lung disease, idiopathic pulmonary fibrosis and emphysema are the predominant manifestations. These patients show variable degrees of BMF and are at risk for clonal abnormalities. In the lung transplant setting, adult telomere syndrome patients have an increased risk of complications due to immunosuppressive medications which challenge their reserves in the bone marrow, intestinal tract and elsewhere. Liver disease, often manifesting as hepatopulmonary syndrome, causes organ failure in approximately 10% of cases. The molecular mechanisms underlying telomere-mediated disease outside the bone marrow likely involve stem cell failure. For example, in the lung, alveolar stem cell senescence is sufficient to drive remodeling, inflammation, and susceptibility to injury, which are hallmark features of pulmonary fibrosis and emphysema. The stem cell failure mechanism has implications for approaching treatment in these lung disorders which have heretofore been considered mediated by inflammation. This session will present evolving scientific evidence that sheds light on the mechanisms and natural history of telomere syndromes. Considerations in the diagnostic work-up of suspected cases and the implications for patient care will be reviewed.

Disclosures

No relevant conflicts of interest to declare.
Mathematical Models of Cancer Evolution and Cure
Authors: Michor Franziska
Published: October 2019

Since the pioneering work of Salmon and Durie, the availability of a quantitative measure of malignant cell burden in multiple myeloma has been used to make clinical predictions and to model tumor cell growth. Here, we analyzed a large set of tumor response data from three randomized controlled clinical trials (total sample size n=1,469 evaluable patients) to establish and validate a novel mathematical model of MM cell dynamics based on responses to bortezomib-based chemotherapy regimens. Dynamics of treatment response in newly diagnosed patients were most consistent with a mathematical model postulating the existence of two tumor cell subpopulations, "myeloma progenitor cells" and "myeloma differentiated cells". Differential treatment responses were observed with significant tumoricidal effects on myeloma differentiated cells and less clear effects on myeloma progenitor cells. We validated this model using a second trial of newly diagnosed MM patients and a third trial of refractory patients. When applying our model to data of relapsed MM patients, we found that a hybrid mathematical model incorporating both a MM differentiation hierarchy and clonal evolution best explains the tumor response patterns in all patients. The clinical data, together with mathematical modeling, suggest that bortezomib-based therapy exerts a selection pressure on myeloma cells that can shape the disease phenotype, thereby generating further inter-patient variability. This model may be a useful tool for improving the rational design of chemotherapy regimens in multiple myeloma.

Disclosures

No relevant conflicts of interest to declare.
Transforming Growth Factor- β1 Signaling in Vascular Endothelial Cells Inhibits Hematopoietic Stem Cell Regeneration
Authors: Zachman Derek , Goldman Devorah C , Guha Chandan , Wilmot Beth , Fleming William H.
Published: October 2019

Endothelial cells (EC) are known to be essential for hematopoietic regeneration; however, little is known about the pathways that regulate this activity. By modeling endothelial-dependent HSC interactions in vitro, we found that human umbilical vein endothelial cells (HUVEC) had a markedly reduced capacity to regenerate functional CD150+LSK cells (HSC) compared to other sources of arterial and venous EC. Transcriptional profiling revealed the overexpression of transforming growth factor- β1 (TGF-β1) in HUVEC and indicated that TGF-β1 driven transcriptional programs are highly active in these cells, a finding consistent with autocrine TGF-β1 signaling. Functional studies demonstrated that HSC regeneration by EC was potently inhibited by TGF-β1 and augmented by the ALK5 inhibitor SB431542, in a dose-dependent manner. Importantly, exposure of EC alone to TGF- β1 was sufficient to attenuate subsequent HSC self-renewal. Transcriptome analysis also identified hepatocyte growth factor (HGF) as a candidate EC-derived factor with the potential to enhance hematopoietic regeneration. HGF treatment of HUVEC activated endothelial Akt signaling and led to a >10-fold increase in HSC regeneration that could be blocked by the c-Met inhibitor PF04217903. HGF treatment also dramatically increased long-term multi-lineage hematopoiesis from HUVEC regenerated HSC. Our findings reveal a novel suppressive role for TGF-β1 in the vascular niche and demonstrate that EC-derived growth factors such as HGF have the potential to attenuate this suppression and significantly enhance HSC regeneration.

Disclosures

No relevant conflicts of interest to declare.