bluuebunny/crossref_metadata_2025_split huggingface dataset:
Follicular Dendritic Cell (FDC)-Induced Microrna-Mediated up-Regulation of PRDM1 and Down-Regulation of BCL6 in Germinal Center B Lymphocytes: A Potential Mechanism for B-Cell Differentiation.
Authors: Lin Jianhong , Lwin Tint , Zhao Jianjun , Zhao Jie , Crespo Luis , Sotomayor Eduardo M. , Moscinski Lynn C. , Dalton William S. , Wright Ken , Tao Jianguo 
Published: October 2019

Abstract
Abstract 4588
B-cell differentiation process is tightly regulated by suppression or induction of specific transcription factors. Among various transcriptional regulators, BCL6 and PRDM-1 are master regulators for germinal center (GC) formation and terminal B-cell differentiation. Dysregulation of BCL6 and PRDM-1 have been associated with lymphomagenesis. However how these transcription factors are regulated and what determines their expression are unclear. Given that follicular dendritic cells (FDC) closely interact with B cells within the GC, provide survival signal to protect B cells from apoptosis and are essential for the differentiation of GC B cells, we used an in vitro FDC-B-cell co-culture model to explore the role of FDC-B cell interaction and FDC-induced miRNA in the regulation of BCL6 and PRDM-1 expression. In this study 1) we revealed that follicular dendritic cells (FDCs, HK) regulate expression of transcription factor (BCL6, and PRDM1) via cell-cell contact, 2) we showed that FDCs regulate expression of B-cell survival and differentiation-related microRNAs, 3) we demonstrated that microRNAs regulate expression of transcription factors BCl6 and PRDM1 and 4) we documented that follicular dendritic cells regulate expression of transcription factor (BCL6, and PRDM1) through microRNAs and plays an important role in B-differentiation. These studies establish new molecular mechanisms for regulation of BCL6 and PRDM-1. FDC-induce miRNA mediated down- and up-regulation of transcriptional factors may contribute to the phenotype maintenance of GC, and pathogenesis of non-Hodgkin's lymphoma (NHL) by interfering with normal B-cell terminal differentiation.

Disclosures:
No relevant conflicts of interest to declare.
In Vitro Knock-Down of Myh9 Leads to a Myh9-Related Disorder Phenotype in Human Megakaryocytes.
Authors: Chen Yolande , Boukour Siham , Romdhane Monia , Seye Ababacar , Bluteau Olivier , Lordier Larissa , Chang Yunhua , Galy Anne , Favier Rémi , Nurden Paquita , Raslova Hana , Vainchenker William , Debili Najet 
Published: October 2019

Abstract
Abstract 4596
Normal platelet production is dependent on the formation of branched long cytoplasmic extensions, called proplatelets (PPT). Mutations of the Myh9 gene (encoding for the nonmuscle myosin heavy chain IIA) result in autosomal dominant disorders, where patients develop various degrees of macrothrombocytopenia, with sometimes glomerular impairment, hearing loss and cataracts. There has been questioning as to whether the mechanism for the macrothrombocytopenia is haploinsufficiency, or a dominant negative effect of the mutated gene. We performed an in vitro study to investigate PPF from patient megakaryocytes (MK). By this approach, a decrease in PPF from patient CD34 derived MKs was observed in comparison to normal cultured MK. Surprisingly this defect of PPF observed in patients was rescued by blebbistatin, an inhibitor of class II myosin. Immunofluorescence studies performed showed that besides clusterization of GPIb in patient's platelets, no major repartition abnormalities were seen in cultured MKs derived from patient's CD34 for myosin, actin, tubulin, vWF, and Rac (except in one patient where actin and Rac formed aggregates to some extend, in a small number of MKs). In order to better understand the role of myosin during normal and abnormal PPF, we used a shRNA strategy to disrupt the Myh9 expression during normal MK differentiation and compared shRNA-treated MKs with MKs derived from patient CD34. Megakaryocytes treated with a shRNA that knocks down the protein of about 50%, did not alter MK ploidization, but decreased in vitro PPF, as previously observed for cells issued from patients. Moreover, shRNA-treated MKs exhibited the same ultrastructural abnormalities as patient MKs. Addition of Blebbistatin to shRNA treated MKs led to an increase of PPF, suggesting that the remaining myosin II might be hyperactivated and inhibit PPF.
Altogether this study strongly suggests that the thrombocytopenia of the Myh9 syndrome is essentially related to haploinsufficiency in myosin II.

Disclosures:
No relevant conflicts of interest to declare.
Splenomegaly with Increased Erythroblast Numbers During Erythropoietic Stress Caused by Ambient Low-Temperature in Mice.
Authors: Maekawa Shun , Iemura Hitomi , Miyazaki Hiroshi , Kato Takashi 
Published: October 2019

Abstract
Abstract 4602
Erythropoietic stress such as hypoxia has been well described in mammals. These conditions decrease oxygen supply and then enhance production of erythropoietin (EPO) regulates production of red blood cells. Moreover, spleen becomes the main organ of erythropoiesis due to limited marrow space. Here, we describe a new erythropoietic stress, ambient low-temperature. It has been reported that peripheral blood cell counts are affected by ambient low-temperature in several vertebrates. Cold-acclimated rat and chicken exhibit polycythemia (Dveci et al, J Comp Physiol, 2001; Yahav S, Poult Sci, 1997). The response is considered to increase demand of tissues for oxygen, and then enhance metabolic rate and capacity for heat production to acclimate to ambient low-temperature. However, the physiological mechanisms had not been investigated. First, we examined peripheral erythrocyte levels in C57BL/6 mice putting into 5°C ambient. Hematocrits increased from 48% to a plateau of 53% after fourteen days. Likewise, hemoglobin concentration, initially 15 g/dl, rose to 17 g/dl. Reticulocyte production index significantly increased from 4% to 8% after seven days. These data suggested that mice exposed to low-temperature enhanced production of erythrocytes, so we next examined the anatomy and cell composition of their spleens. On day 5, spleens were about 6 mg/g of body weight, two-fold those on day 0. They gradually decreased to their initial weights on day 14. Flow cytometry showed 38% more Ter119+ splenocytes and four-fold more CD71 high Ter119+ early erythroblasts than normal. These values also gradually declined to their initial numbers by day 14. The results suggested the elevated red blood cell counts were due to an increase in production. To test erythropoietic activity in serum, we used an erythrocyte colony-forming assay. Serum from mice kept at low-temperature showed no ability to stimulate CFU-E colony formation in vitro. However, a combination of the serum with EPO (0.5 U/ml) increased CFU-E numbers 1.5 to 2 times that of a combination of normal serum plus EPO or EPO alone. Whether inducible factors account for these effects is the focus of future investigation. Our findings suggest a low-temperature environment is an erythropoietic stress that may offer insights into the adaptive physiology of red blood cell production in mice.

Disclosures:
No relevant conflicts of interest to declare.
Pain Rate and Social Circumstances Rather Than Cumulative Organ Damage Determine the Quality of Life in Adults with Sickle Cell Disease.
Authors: van Tuijn Charlotte F.J. , van Beers Eduard J. , Schnog John-John , Biemond Bart J. 
Published: October 2019

Abstract
Abstract 4605

Background
Previous studies have demonstrated a significantly reduced quality of life (QoL) in sickle cell patients which appeared to be related to the significant morbidity associated with sickle cell disease such as frequent painful crises. With the longevity of sickle cell patients in the Western world chronic organ damage may also be an important factor to the QoL of sickle cell patients. Furthermore, not directly disease related factors such as socioeconomic circumstances may also be important in the general well being of these patients.

Aim of the study
First, to determine the contribution of chronic organ damage and cumulative sickle cell related complications to QoL of sickle cell patients in the Netherlands. Second, we analysed the effect of socio-economic circumstances on QoL in our patients.

Methods
Consecutive adult sickle cell patients cared for in a teaching hospital were included. QoL was assessed with SF-36 forms and was represented in a physical component scale (PCS) and a mental component scale (MCS). In all patients a systematic evaluation of chronic organ damage was performed including: pulmonary hypertension, renal failure, microalbuminuria, retinopathy and iron overload. In addition, sickle cell related complications including: the frequency of painful crises, chronic leg ulcers, avasculair osteonecrosis, stroke, acute chest syndrome and priapism were assessed in the previous five years by chart review. We studied the QoL scores in relation to presence of chronic organ damage, sickle cell related complications and socioeconomic circumstances (patients occupation and educational level).

Results
A total of 96 patients were included in our study. The presence of chronic organ damage was not related to the QoL of our patients despite the incidence of pulmonary hypertension in 24% of our patients. Of the sickle cell related complications in the previous five years, pain rate was significantly associated with mental component score (MCS) but not with the physical component score (PCS). With respect to the socioeconomic circumstances, 35% of the sickle cell patients were unemployed as compared to 6% of the general population and 16% of immigrants without SCD. Both occupation and the level of education were significantly related to PCS while no relation with MCS or pain rate was found.

Conclusion
In sickle cell patients in Amsterdam, the Netherlands, QoL is mainly determined by pain rate and socioeconomic circumstances such as occupation and educational level. Chronic organ damage, although a major factor determining life expectancy in SCD, was not a determinant of QoL.

Disclosures:
No relevant conflicts of interest to declare.
Current Epidemiology and Hospitalization Characteristics for Acute Chest Syndrome: A Nationally Representative Survey.
Authors: Goel Ruchika , Viswanathan Prabhu , Krishnamurti Lakshmanan 
Published: October 2019

Abstract
Abstract 4608

Background
Acute chest syndrome (ACS) is a major cause of morbidity and the leading cause of mortality in patients with sickle cell disease (SCD). While the causes, outcome, and response to therapy in ACS has been described before, there is scant literature on current nationally representative estimates of burden, characteristics and cost of hospitalizations for SCD patients with ACS.

Methods
The Nationwide Inpatient Sample (NIS) database, sponsored by the Agency for Health Care Quality and Research, is a stratified probability sample of 20% of all hospital discharges among U.S. community hospitals (n=1,044, sampling universe = 90% of all such discharges). Sampling weights were applied to represent all community hospital discharges in the US for the year 2007.
Presence of following ICD-9-CM diagnosis codes were used to define SCD related hospitalizations: 28241, 28242, 2825, 28260, 28261, 28262, 28263, 28264, 28268, and 28269. ICD-9-CM 517.3 was used to identify ACS as a diagnosis during hospitalization for SCD. Only data on SCD related hospitalizations were analyzed.

Results
In 2007, there were 86,318 discharges nationwide with a primary diagnosis and 79,766 with a secondary diagnosis of SCD (total=166,084). Of these, 7039 (4.2%) had ACS as a complication. Though, males represented 37.5% of SCD related hospitalizations but accounted for 52.1% of ACS episodes. ACS was more common complication in those with age <18 yrs than 18-44 age group (8.1% vs. 3.5%)
Pulmonary hypertension as one of the discharge diagnosis was reported in 4.7% of the patients with ACS as compared to 2.2% of the patients without ACS (p <0.001). At least one simple transfusion was seen in 43.0% of SCD patients admitted with a ACS compared to 21.7% without ACS (p-value <0.001). Exchange transfusion (3.6% vs. 0.4%; p <0.001) and mechanical ventilation (2.2% vs. 0.7%; p<0.001) were more frequently among hospitalizations with ACS than without it.. The mean (SD) length of hospitalization in SCD patients with ACS was higher (6.9±0.3 vs. 5.2±0.1; p<0.001) than those without ACS. The mean length of stay by various age categories is depicted in Table 1. Presence of ACS was associated with significantly higher mean charges per hospitalization (USD 35145 vs. USD 22836; p<0.001) Higher in-hospital mortality (1.3% vs. 0.5%, p<0.001) was seen among SCD hospitalizations with ACS as complications than without. The majority of deaths were in the 18-44 years age group (69.9%) followed by 18.2% deaths in <18 years group.

Conclusions
ACS is a major and common complication in hospitalizations with SCD as a discharge diagnosis. Among SCD patients, presence of ACS is associated with an increased risk of receiving a simple or exchange transfusion, mechanical ventilation, increased length of hospital stay, higher hospital charges and in-hospital mortality.

Disclosures:
No relevant conflicts of interest to declare.
Improved T Cell Recovery After Transplantation of CD3/CD19 depleted Haploidentical Stem Cell Grafts in Pediatric Patients.
Authors: Teltschik Heiko-Manuel , Feuchtinger Tobias , Pfeiffer Matthias , Schumm Michael , Mueller Ingo , Handgretinger Rupert , Lang Peter J. 
Published: October 2019

Abstract
Abstract 4652
Profound depletion of T and B cells is a fundamental prerequisite for haploidentical transplantation and allows to minimize GvHD despite HLA incompatibility. However, posttransplant recovery of donor derived T cells is delayed after various graft manipulation procedures and may result in severe infections. Methods to improve this recovery are of great importance. Here we present immune reconstitution data in patients who received CD3/CD19 depleted stem cells in combination with melphalan based or standard conditioning regimens.
32 patients with ALL (n=14), AML/MDS (n=17), CML (n=1) were included. T and B cells were directly depleted using antiCD3/antiCD19 coated magnetic microbeads and the CliniMACSTM device.
The patients received either TBI or Bu i.v. and OKT3 (n=9) or a reduced intensity conditioning (“RIC”: Mel 140mg/m2, Flud 160mg/m2, TT 10mg/kg, OKT3, n= 23).
Absolute numbers of lymphocyte subsets per microliter on day 90 were compared within these both groups and with a historical control group (patients with leukemias who received CD34 selected grafts and TBI or Bu based standard conditioning regimen in combination with ATG, n=28).
CD3+4+, CD3+8+ and total numbers of CD3+ of patients after CD3/CD19 depletion were significantly higher in the RIC-group than in the TBI/Bu-group (mean numbers: 85.83 vs. 38.84; 133.46 vs. 19.69; 270.27 vs. 63.99; p<0.05, unpaired t-test).
Comparison with the whole CD34 historical group showed a faster recovery of CD3+4+ in patients with CD3/19 depletion and RIC (104.26 vs. 54.22; p= 0,034) but no significant difference in CD3+8+ and CD3+. Furthermore, subgroups of the CD34 historical population were compared: patients with CD3/19 depletion and RIC had a significantly faster recovery of CD3+4+, CD3+8+ and CD3+ than CD34 patients with TBI (104.26vs. 25.48; 133.46vs. 43.17; 270.27 vs. 65.86; p<0.05) but had no advantage over CD34 patients with non-TBI conditioning.
Conclusions: the type of graft manipulation appeared to have an influence on the speed of CD4+ recovery (CD3/19 depletion > CD34 selection). Moreover, the use of TBI had a clear negative impact on all T cell subsets: patients with TBI had a slower recovery than patients with non-TBI conditioning, independent from graft manipulation procedures and probably due to thymic damage. Thus, the use of RIC-protocols in combination with CD3/CD19 depletion may help to speed up the immune recovery after haploidentical transplantation. Further studies are warranted to evaluate the risk of relapse.

Disclosures:
No relevant conflicts of interest to declare.
HHV-6 Reactivation Lowers the Risk of Acute Graft-Versus-Host Disease but Enhances the Risk of Infections Due to Activation of CD4+FoxP3+ Lymphocytes.
Authors: Lange Andrzej , Jaskula Emilia , Madej Sylwia , Dlubek Dorota 
Published: October 2019

Abstract
Abstract 4653
CMV, EBV, and HHV-6 reactivation was monitored for 20 days to 4 years after allogeneic hematopoietic stem cell transplantation (alloHSCT) with respect to hematological and immunological reconstitution as well as fate in 118 patients (17 children and 101 adults) who received alloHSCT (100 peripheral blood progenitor cell (PBPC) and 18 bone marrow transplants from 53 siblings and 65 unrelated donors, 64 patients receiving reduced intensive conditioning (RIC) and 54 myeloablative conditioning). All patients on RIC and those transplanted from unrelated donors received anti-thymocyte globulin (ATG). Herpes virus DNA copies were measured by quantitative PCR (primers and probes designed according to Kimura 1999, Machida 2000, and Locatelli 2000). This study focused on HHV-6.
It was found that:Multivariate analysis showed that alternative donor (OR=3.06, p=0.038), myeloablative conditioning regimen (OR=0.22, p=0.004), and an HLA-matched (10/10 at allele level) graft (OR=0.14, p=0.011) were risk factors of HHV-6 reactivation. Interestingly, they were different from those of CMV reactivation (acute GvHD grade >=I, OR=2.74, p=0.024).HHV-6 reactivation was found earlier post-transplant than CMV reactivation (19 vs. 47 days, median values, p=0.014) and rather before clinically apparent aGvHD manifestation, in contrast to CMV and EBV infections (percentages of reactivation events prior to aGvHD were 71, 14, and 14 for HHV-6, CMV and EBV, respectively).HHV-6 was associated with an increase in CD4+ lymphocytes (p=0.028, Wilcoxon matched pairs test), in contrast to CMV infection, in which CD4+ cells were rather low.HHV-6 reactivation noted during 100 days post-transplant was associated with a higher fraction of FoxP3+ in CD4+ cells compared with those of counterparts (13% vs. 8.5%, median values, p=0.008).Encephalitis was frequent in HHV-6 (8/14 vs. 26/104, p=0.023) and EBV (9/14 vs. 22/104, p=0.002) positive patients. HHV-6 preceded EBV (14/26 vs. 28/92, p=0.037) but not CMV (9/36 vs. 33/82, p=0.145) reactivation before 100 days after HSCT.HHV-6 positivity in the 100 days post-HSCT was associated with a higher mortality rate early post-transplant (6-month survival rates of HHV-6-positive and -negative cases: 55% vs. 80%, respectively).
In conclusion: HHV-6 reactivation affects patients early post-transplant and associates with an increase in CD4+ lymphocytes in blood which frequently have FoxP3 generation potential. Risk of aGvHD is consequently lower, but there is a higher incidence of infections, including EBV, encephalitis, and sepsis, and survival is poor.

Disclosures:
No relevant conflicts of interest to declare.
Efficacy and Safety of Micafungin as An Empirical Antifungal Agent for Febrile Neutropenic Patients with Hematological Diseases.
Authors: Park Joon Seong , Kim Dong Hwan , Choi Chul Won , Jeong Seong Hyun , Choi Jin-Hyuk , Kim Kihyun , Kim Seok Jin , Jung Chul Won , Yang Deok-Hwan , Kim Hugh Chul , Jang Jun Ho 
Published: October 2019

Abstract
Abstract 4661

Introduction
Invasive or possible fungal infection is often fatal and its incidence is increasing in febrile neutropenic patients with hematological malignancies. Thus, empirical antifungal agent should be carefully selected for those patients.

Patients and Methods
The study was conducted as a prospective multicenter trial to document the efficacy and safety of micafungin (Mycamine®), a class of echinocandin, as an empirical antifungal agent in febrile neutropenic patients. Micafungin was administrated for sustained fever (>38.4°C) on day 3 - 5 after initiation of empirical antibiotic therapy. The overall success rate according to the composite score (no breakthrough fungal infection, survival for seven days beyond the end of therapy, did not discontinue therapy prematurely, had resolution of fever during the period of neutropenia, and successfully treated a documented base-line fungal infection) and side effects were evaluated.

Results
A total of 47 patients with AML, ALL, MDS or lymphomas were enrolled. The overall success rate was 61.7% (29/47). Three patients (6.4 %) experienced grade 3/4 elevated aspartate aminotransferase and ten patients (21 %) showed grade 3/4 hyperbilirubinemia and nine of which resolved, and four patients died of septic shock. Patients with young age (< 50 yr) and ALL rather than AML showed a better response to micafungin. Less profoundly neutropenic (≥50 /mm3) patients revealed a better response, as did the patients who recovered from fever or neutropenia.

Conclusions
Micafungin has been reported to have an excellent efficacy (61.7 %) and safety profile when used as an empirical antifungal agent to treat febrile neutropenic patients with hematological disorders.

Disclosures:
No relevant conflicts of interest to declare.
Favorable Transplantation Outcomes Associated with Early Recovery of Lymphocytes and CD8+ Cells Following Allogeneic Stem Cell Transplantation.
Authors: Moon Joon Ho , Cho Yoon Young , Kang Byung Woog , Kim Shi Nae , Lee Soo Jung , Kim Yun Jeong , Suh Jang Soo , Lee Kun Soo , Park Jae Hoo , Sohn Sang Kyun 
Published: October 2019

Abstract
Abstract 4665

Background
Immune reconstitution is an important component for successful transplantation. The laboratory parameters regarding immune reconstitution at 3 months after allogeneic stem cell transplantation (SCT) were analyzed in the current study.

Methods
To assess the kinetics of lymphocyte subset recovery, 128 patients who underwent allogeneic SCT and survived at least 3 months after transplantation were monitored by surface markers (CD3, CD4, CD8, CD19, CD56).

Results
Factors affecting CD4+ cell recovery at 3 months after transplantation included the use of cyclosporine instead of tacrolimus (odds ratio [OR]=0.256, p=0.007), in vivo T-cell depletion (OR=0.263, p=0.001), and use of peripheral blood stem cells instead of bone marrow (OR=0.281, p=0.016). The overall survival (OS) was better for the patients with early recovery of absolute lymphocyte counts (ANC, >1500/mm3), CD3+ (>1000/mm3), CD4+ (>300/mm3), CD8+ (>600/mm3), and CD19+ cells (>30/mm3). But CD56+ NK cell recovery (>300/mm3) failed to predict better survival. The patient group with early recovery of ANC, CD3+, and CD19+ cells showed a lower relapse rates. Treatment related mortality (TRM) was lower for the patients with early recovery of ANC, CD3+, and CD4+ cells. Chronic graft-versus-host disease (GVHD) was not related with the lymphocyte recovery. In the multivariate analysis, high risk disease status (hazard ratio [HR]=1.903, p=0.031), acute GVHD ≥grade 2 (HR=1.975, p=0.039), and HLA mismatch (HR=4.124, p=0.002) were significantly associated with lower OS, whereas, early recovery of ANC (HR=0.455, p=0.047) and CD8+ cells (HR=0.485, p=0.057) at 3 months showed a better survival.

Conclusion
Faster lymphocyte recovery and CD8+ cell recovery at 3 months after allogeneic SCT showed a better survival and lower TRM rate.

Disclosures:
No relevant conflicts of interest to declare.