bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mef2C Maintains B Cell Homeostasis Through the Regulation of DNA Repair Machinery
Authors: Wang Wenyuan , Montel-Hagen Amelie , Sasidharan Rajkumar , Mikkola Hanna K. A. 
Published: October 2019

Abstract
Abstract 278
B lymphocytes are central mediators of humoral immunity as they are able to bind specifically to an antigen through B cell receptor (BCR) and generate antibodies against the antigen. During aging, specific reduction of bone marrow pre-B cells and defects in BCR rearrangement result in declined B lymphopoiesis and contribute to immunosenescence.
One novel regulator of B cell homeostasis is Mef2C, a MADS-box transcription factor that activates target genes by binding to the MEF2 consensus binding site. Using VavCre+ Mef2Cfl/fl mice that ablate Mef2C in hematopoietic cells, we observed a specific reduction in the bone marrow pre-B cell already in young adults – a phenotype that resembles B cell aging. Loss of Mef2C resulted in higher percentage of late apoptotic and necrotic (AnnexinV+, 7AAD+) pre-B cells, suggesting a requirement for Mef2C in pre-B cell survival.
To investigate the mechanism that Mef2C uses to regulate B lymphoid homeostasis, we performed gene expression study. Gene Ontology analysis of Mef2C dependent genes in pre-B cells showed a significant down-regulation of DNA repair and cell cycle genes. Furthermore, by searching for the MEF2 consensus binding site, we identified critical regulators of cell cycle (Ccnb1&2,E2F2, E2F6) and DNA damage response (Ercc8, H2afx, Mre11a, Rad51ap1, Rad54l, Rpa1) as putative Mef2C direct targets in pre-B cells. To functionally assess the requirement for Mef2C in DNA damage response, we performed radio-sensitivity analysis. Upon 6Gy irradiation, Mef2C deficient mice showed a dramatic ablation of peripheral blood B cells as compared to controls while their T and myeloid cells remained largely unaffected. These data suggest that Mef2C regulates DNA repair machinery to protect B lymphocytes against irradiation induced stress.
Pre-B cell stage is a vulnerable step of B lymphopoiesis as successful BCR rearrangement is required for the pre-B cell receptor (pre-BCR) to support pre-B cell survival and expansion. DNA repair is a critical step during V(D)J recombination. Interestingly, in absence of Mef2C, V(D)J initiators (Rag1&2) and critical DNA repair effectors (Ku70, Xrcc4 & Lig4) failed to be upregulated during pro-B to pre-B transition as they did in controls. Furthermore, loss of Mef2C in both pro- and pre-B cells resulted in decreased expression of surrogate light chain genes (VpreB1&2) and recombined IgH μ chain.
These findings define Mef2C as a lineage specific DNA repair regulator that links the classical DNA repair machinery to B cell factors and guards B lymphoid homeostasis at an inherently precarious developmental stage.

Disclosures:
No relevant conflicts of interest to declare.
Splenectomy for Massive Splenomegaly Associated with Myelofibrosis: Outcomes From 63 Patients At Mayo Clinic.
Authors: Singh Preet Paul , Timucin Taner , Nagorney David M , Tefferi Ayalew 
Published: October 2019

Abstract
Abstract 2848

Background:
Massive splenomegaly (MS) (>1500 grams) is a rare and overtly symptomatic manifestation of myelofibrosis. While splenectomy may provide palliation, the procedure may be technically difficult and lead to high operative risks. We retrospectively analyzed myelofibrosis patients who underwent splenectomy for MS to analyze complications and outcomes.

Methods:
Retrospective chart review of all patients with myelofibrosis at our institution who underwent splenectomy for MS between 1998 and 2006 was performed. MS was defined as post-operative spleen weight measured to be more than 1500 grams. A total of 63 patients with MS had splenectomy for palliation of pressure symptoms or transfusion requiring cytopenias during that time period. Kaplan Meier statistics and log rank test were used for survival analysis.

Results:
Mean age of the study patients was 64.9 ± 9.5 years and 56% of those were males. Commonest pre-splenectomy symptoms were left upper quadrant abdominal discomfort (85.7%), fatigue (81%), early satiety (76.2%), anorexia (54%) and weight loss (39.7%). Packed red blood cell and platelet transfusions were required pre-operatively in 36/63 (57.1%) and 10/63 (15.9%) of patients, respectively. Median spleen weight was 2805 (range 1540 – 13085) grams. Perioperative complications occurred in 15 patients (23.8%) including infection (= 4 patients [6.3 %]), thrombosis (= 6 patients [9.5%]), or bleeding (= 9 patients [14.3%]), 2 of which (3.2% of all patients) were fatal.
Median post-splenectomy survival (PSS) of these patients was 16.4 (0–110) months and 5 year PSS was 20%. Excluding patients lost to follow up, 43/55 (78.2%), 33/55 (60%) and 26/54 (48.1%) patients were alive at 6 months, 1 year and 2 years after splenectomy, respectively. At 1 year, out of 33 alive patients, 24 (72.7%) patients had relief of pressure symptoms. Out of 36 patients who were red cell transfusion dependent pre-splenectomy, 13 were alive and 6/13 (46.2%) patients were transfusion independent at 1 year. Similarly, out for 10 patients requiring platelet transfusions pre-operatively, 5 were alive and 3/5 (60%) were transfusion independent after 1 year follow up.
PSS after splenectomy for MS was decreased in patients that required pre-operative packed red cell transfusions (median 9.3 months vs. 32.1 months, p= 0.033) (Fig 1), but not affected by other factors including age (>64 years), pre-operative thrombocytopenia (<100 × 109/uL), prolonged operative time (>90 minutes) or larger spleen size (>2800 grams).

Conclusions:
Splenectomy is relatively safe and effective palliative treatment for pressure related symptoms and refractory cytopenias related to MS in patients with myelofibrosis. Pre-operative anemia requiring red cell transfusions may predict advanced disease and is associated with inferior PSS.

Disclosures:
No relevant conflicts of interest to declare.
Trial Sequential Analysis in Meta-Analyses of Maintenance Therapies for Multiple Myeloma.
Authors: Miladinovic Branko , Kumar Ambuj , Mhaskar Rahul , Mahoney Helen , Wheatley Keith , Djulbegovic Benjamin 
Published: October 2019

Abstract
Abstract 2975

Background:
Meta-analyses (MAs) with few participants (i.e. small number of primary studies) are at risk of producing random errors and consequently overestimating treatment effects. With insufficient information the risk of obtaining a false positive result (type I error) increases, which may lead to false conclusions. Trial sequential analysis (TSA) has been proposed as a method to ascertain whether results of MAs are conclusive (true vs. false positive, true vs. false negative). It adjusts for the risk of random error by constructing monitoring boundaries under the sample size necessary to conclude significant treatment effect. In TSA, the information size is calculated based on a pre-specified event rate in the control group, a minimum intervention effect (risk ratio reduction), and a desired maximum risk of type I error α and type II error β. Here we apply TSA on MAs of randomized controlled trials of maintenance therapies in the management of multiple myeloma.

Methods:
A comprehensive literature search of MEDLINE (PubMed), the Cochrane Central Register of Controlled Trials (CENTRAL), and meetings abstracts from American Society of Hematology, American Society of Clinical Oncology, European Society for Medical Oncology and European Hematology Association was undertaken to identify all phase III randomized controlled trials (RCTs) of maintenance therapy published until July 2012. We extracted data on overall survival and progression-free survival comparing treatments that could be pooled in random effects meta-analysis. We performed TSA for the apriori diversity-adjusted information size (APDIS) under risk ratio reduction of 20% and 25%. The information size was adjusted for between-study trial diversity, which is defined as the total relative variance expansion changing from a fixed effect into a random effects meta-analysis. We used two-sided α = 5% and 1 – β = 80% power. All analyses were done in Stata 11.2 using metacumbounds command.

Results:
Nine separate meta-analyses (18 randomized controlled trials) met the inclusion criteria (Table 1). The median number of patients was 1193 (range 351–2824) and median diversity 0% (range 0%-91%). Under both risk ratio reductions of 20% and 25%, 4/9 MAs were false negative and 1/9 false positive. The observed power based on the accrued sample size and observed risk ratio reduction was greater than 80% in 5/9 MAs.

Conclusion:
TSA detected one false positive MA of two trials comparing thalidomide with prednisone/dexamethosone for the outcome of overall survival. Future MAs need to consistently undertake TSA to avoid misleading conclusions.

Disclosures:
No relevant conflicts of interest to declare.
Plasmablastic Lymphoma Is Curable The HAART Era. A 10 Year Retrospective By The AIDS Malignancy Consortium (AMC)
Authors: Noy Ariela , Chadburn Amy , Lensing Shelly Y. , Moore Page 
Published: October 2019

Abstract

Background
The highly aggressive plasmablastic lymphoma (PBL), originally described almost exclusively in HIV+ patients, was nearly uniformly fatal in the pre-HAART era. We hypothesized that aggressive chemotherapy and HAART could result in cures.

Methods
We retrospectively analyzed baseline characteristics, treatment patterns and outcomes of patients (pts) with PBL treated at multiple centers within the AIDS Malignancy Consortium (AMC). HIV positivity was not required. 19 confirmed PBLs from 9 national AMC sites diagnosed between 1999 and 2008 were evaluated.

Results
17/19 patients (pts) with confirmed PBL were HIV+. Data was captured at initial diagnosis on 12 pts (all HIV+) and 7 with relapsed/refractory disease (5 HIV+). HAART status at PBL initial diagnosis was 33% on, 58% off, and unknown 8%. Median CD4 count 110 (range 4-658). First line chemotherapy was given to 10/12 (83%) newly diagnosed patients with stage I/II (6) vs III/IV(6) disease. This was CHOP(4), CDE (1), EPOCH (2) and EPOCH with high dose methotrexate and zidovudine (2). Second line therapy was given to 5/7 relapsed/refractory patients with stage I (1) vs Stage III/IV (5) disease and a median CD4 83 (range 10-202): EPOCH alternate HD Mtx+AZT (n=1); Hyper-CVAD (n=2); High dose Mtx + AZT (n=1); VACOP-B(n=1). One pt underwent BEAM based autologous stem cell transplant. For both groups combined, 6 patients experienced grade 3/4 toxicity. Febrile neutropenia was the most common grade 3/4 toxicity (4 patients) followed by thrombocytopenia (3 patients). One patient with refractory disease experienced grade 5 toxicity. For the 12 newly diagnosed patients, 8 patients were alive at last follow-up and 4 had died. Median follow-up for survivors was 73 (range, 40-165) weeks. One-year survival was 66.7% (SE, 13.6). See Figure 1. For the 7 relapsed/refractory patients, 2 patients were alive at 24 and 54 weeks, and 1 was lost to follow-up. One-year survival was 53.6% (SE, 20.1%).

Conclusions
In the HAART era, aggressive treatment of PBL can result in significant survival times.
However, determination of the superior treatment regimen could not be determined from this small patient sample. CTSU 9177 is prospectively studying PBL with EPOCH.

Disclosures:
No relevant conflicts of interest to declare.
The Platelet-Derived Microparticles Related to the Clinical Phenotype Heterogeneity of Hemophlia a
Authors: Qin Fangmei , Huang Shunhua , Li Zhitao , Ye Jieyu , Sun Jing 
Published: October 2019

Abstract
Keywords: Hemophlia A, Phenotype; Heterogeneity; Flowcytometry ; Mircoparticle
Background: The clinical phenotype for hemophlia A are typically recognized sub-clinical, mild, moderate and severe according to the residue FVIII level of the plasma. For recent years, there are evidences indicate that the residue FVIII level is not the only factor relate to the clinical phenotype of patients with severe hemophlia A. Platelets are an important role in hemostasis and platelet-derived microparticles (PMPs) are known to mediate a prothrombotic state in patients, we hypothesized that PMPs contributes to the clinical phenotype heterogeneity of hemophilia A patients.
Methods: Thirty-one patients with severe hemophlia A (FVIII:C<1%, age 18-33 yrs, median 23.5 yrs) treated on demand were enrolled in this study, including 10 patients with mild type(FVIII:C<1%, but annualized bleed rates<6) and 21 patients with severe type (FVIII:C<1% and annualized bleed rates≥24). Seventeen healthy male donors were selected as normal controls. We also compared the baseline PMPs counts from eleven patients on demand treatment to that when they had three months prophylactic treatment. Venous blood was anticoagulated with sodium citrate (1:9). Plasma was isolated (1550g for 20 min at RT) and then cell free supernatant was ultracentrifuged (18,000g for 20 min at 20°C). The supernatant plasma samples were measured for baseline PMPs counts, with phycoerythrin (PE)-conjugated monoclonal antibodies CD41, CD42b, CD61, CD62P, and CD63 specific for PMPs derived from platelets respectively. Analyzed by flow cytometry, Forward scatter was set in scale using fluorescent microspheres of 1.0μm and standard fluorescent microbeads (0-1.0μm) in diameter were used to set the microparticle gate. Statistics were performed using independent-samples T test
Results: There was a trend toward higher the mean level of PMPs counts in mild type patients compared to severe type (mean ± SD: 2.06±1.33 vs 0.95±0.64, p = 0.02), the PMPs counts of normal individuals was significantly higher than severe type(mean ± SD: 1.06±1.20 v s0.95±0.64, p = 0.02), significantly lower than mild type (mean ± SD: 1.06±1.20 vs 2.06±1.33, p = 0.02). The PMPs counts decreased after 3 months low dose (10 iu/kg, 2-3/w) prophylacticlly treatment (mean ± SD: 6.50±0.51 vs 0.45±0.50, p = 0.00).
Conclusion/Discussion: Platelet-derived Microparticles (PMPs) are generated in response to platelet activation, our observations demonstrate that the PMPs counts differs in patients of severe hemophlia A, the mean lever of PMPs in mild clinical phenotype patients was higher than the severe type, prophylacticlly treated patients has a lower PMPs lever, PMPs is likely to play a role in clincal phenotype heterogeneity of sever hemophilia A.

Disclosures
No relevant conflicts of interest to declare.
Value and Implications of the Anti-Xa Activity Monitoring for Prophylactic Dosing Adjustment of LMWH in Pregnancy: A Retrospective Study
Authors: Paulus Samuel , Lambert Catherine M , Boban Ana , Hermans Cedric R. 
Published: October 2019

Abstract

Introduction: Low molecular weight heparins (LMWH) have stable pharmacokinetics. However, physiologic changes during pregnancy can alter pharmacokinetics of LMWH and make the biodisponibility of the drug less predictable. When starting prophylactic treatment with LMWH in pregnant woman, most physicians calculate the initial LMWH dose based on the body weight and adapt the dose according to the weight gain. An alternative method is to monitor the anti-Xa activity and adjust the LMWH dose accordingly. LMWH are for the moment the only anticoagulant available for prophylaxis of venous thrombo-embolism in pregnant women and prevention of severe pregnancy complications. Therefore, we conducted a study addressing the rationality of performing an anti-Xa activity monitoring regularly during pregnancy.
Methods: We retrospectively analyzed data from pregnant women undergoing prophylaxis with LMWH followed at the Hemostasis and Thrombosis Unit of the Saint-Luc University Hospital Unit. All the patients that had anti-Xa activity done at least three times during pregnancy were included in the study. The measurements of anti-Xa were done regularly every 6 weeks and the dose of LMWH was increased in case of anti-Xa activity lower than 0.3 U/ml. Initial LMWH dose was calculated based on the patient body weight and the first measurement of anti-Xa done 10 days afterwards.
Results: Out of 173 women evaluated in the study, 79% needed LMWH dose adjustment. 97 patients (56%) had one dose adjustment, 35 patients (20%) two and 5 patients (3%) three. The first augmentation of LMWH dose was needed before the patient gained body weight in 36,5% of cases. The average increase of the LMWH dose was 49%, 100% and 116% for the one, two and three dose adjustments, respectively. Under-dosing of LMWH, defined as anti-Xa activity <0,2 U/mL, was present in 12% of patients on the first monitoring versus 3,5% on the last monitoring visit. No severe side effects occurred during the treatment. Five patients (3%) had unfavorable outcome of the pregnancy.
Conclusions: This study demonstrates that regular monitoring of anti-Xa activity can help in maintaining the prophylactic levels of LMWH throughout the pregnancy. We also showed that the reduction of the anti-Xa activity is not always directly correlated with the weight gain in pregnant women. Therefore we recommend that LMWH dose adjustment should not be made based solely on the weight gain of the patient during pregnancy.

Disclosures
No relevant conflicts of interest to declare.
The Prognostic Significance of the Absolute Lymphocyte to Monocyte Count Ratio (ALC/AMC-dx) at Diagnosis in Hodgkin´s Lymphoma
Authors: Acosta-Maldonado Brenda Lizeth , Ramirez-Ibarguen Ana , Grimaldo-Gomez Flavio A , Oñate-Ocaña Luis , Rivas-Vera Silvia 
Published: October 2019

Abstract
Background. In Classic Hodgkin's lymphoma (cHL), malignant cells constitute only about 1% of the bulk of tumor tissue, the rest constitutes the microenvironment and is made up of a compound of inflammatory cells. Lymphocytopenia and increased CD68+ tumor-associated macrophages (TAMs) are adverse prognostic factors in cHL. TAMs are derived from circulating monocytes and are possibly related to absolute monocyte count (AMC). We have sought to investigate the relationship of circulating lymphocytes and monocytes with response and survival in patients. Recently, Porrata et al. reported that a low absolute lymphocyte count/absolute monocyte count at diagnosis [ALC/AMC-Dx] (<1.1) is an independent prognostic factor in cHL. Subsequent studies used different cutoffs for ALC/AMC (1.5 and 2.9). Currently, there are no studies that evaluate the usefulness of the index relative to the overall response.
Aim To determine the prognostic value of ALC /AMC at diagnosis in patients with cHL and its impact on treatment response to therapy, progression and overall survival.
Methods: We evaluated 262 consecutive individuals with cHL, referred and treated at the National Cancer Institute in Mexico between 2006 to 2013. The great majority of patients were treated with ABVD with or without radiotherapy, and all had available data for ALC/AMC determined at diagnosis. It was made a multivariate analysis and ROC curves for cutoff point of ALC/AMC.
Results: Median age was 35 y (14-89), 59.2% of patients were male, 77% had B-symptoms, 36.3% had stage IV disease, 85% had advanced stage (IB,IIB,III,IV), 51.5% had IPS ≥3, 46.2% nodular sclerosing histology and 45.4% mixed cellularity. The overall response (CR + PR) was obtained in 188 patients (72%) and failure (stable disease or progressive disease) in 73 patients (28%). A new cutoff point, 1.77 in ALC/AMC-Dx ratio with area under the curve of 0.62. Multivariate analysis showed that the ALC/AMC-Dx index was an independent predictor for response to treatment, progression as well as overall survival (Table 1). Additionally the IPS≥3 showed to be an independent factor for response 68.8% vs 41.7% in low and high risk, respectively (p<0.0000).
Conclusion: In our population ALC/AMC-Dx index was established with a cutoff of 1.77. The group of patient with < 1.77 had a less overall response and overall survival. It proves that ALM/AMC-Dx is an independent predictor of response, progression and overall survival in patients with classical cHL. That differs of other reviews where the cutoff was lower.
Table 1. Multivariate analysis according to ALC/AMC-DX ratio ALC/AMC -Dx index p Low< 1.77 High >1.77 Overall Response 58.1% 79.8% OR 0.25-.0.84p 0.011 Overall Survival8 years 81% 94% p 0.004

Disclosures
No relevant conflicts of interest to declare.
Circulating Plasma Cells in Newly Diagnosed Symptomatic Multiple Myeloma As a Prognostic Marker for Patients with Standard-Risk Cytogenetics
Authors: Vagnoni Davide , Travaglini Fosco , Angelini Stefano , Dalsass Alessia , Mestichelli Francesca , Angelini Mario , Pezzoni Valerio , Natale Annalisa , Ruggieri Miriana , Bigazzi Catia , Troiani Emanuela , Falcioni Sadia , Mazzotta Serena , Galieni Piero 
Published: October 2019

Abstract
Multiple Myeloma (MM) is a clonal B-cell disorder characterized by accumulation of malignant plasma cells (PCs) in the bone marrow (BM). Circulating PCs can be detected in the peripheral blood of a significant proportion of patients with MM and their presence is a well-known prognostic factor. Indeed, the appearance of circulating PCs in the blood could indicate relative indipendence from adhesion to the microenvironment, thus implying more aggressive disease. In this study, we examined the relationship between the number of PCs and citogenetic risk in patients with newly diagnosed MM.
We analyzed peripheral blood from patients with Monoclonal Gammopathy of Undetermined Significance (MGUS; n=15), Smoldering Myeloma (SM; n=28), Solitary Plasmacytomas (SP; n=3) and active Multiple Myeloma (MM; n=105). These patients were followed by the U.O.C. Ematologia at the "Mazzoni" Hospital from January 2006 to December 2013, with a median follow-up of 25 months. We analyzed clinical, laboratory and cytogenetic data of patients with active MM. However, cytogenetic analysis was not evaluable for 15 patients. The number of circulating PCs was detected by flow cytometry using a simple two-colours approach. Cells were stained with fluorescence-labeled CD38 and CD45 antibodies and 50,000 events were acquired and analyzed for each patient. PCs were identified by gating on CD38bright+/CD45- cells.
Using a receiver operating characteristics (ROC) analysis, we assessed that ³41circulating PCs is the optimal cut-off for defining poor prognosis.
The 8-years probability of Overall Survival (OS) and Progression-Free Survival (PFS) in patients with <41 and ³41circulating PCs, was 32% vs 8% (p=0.017) and 29% vs 0% (p=0.0008), respectively. Patients with high-risk cytogenetics (n=24) had poor prognosis, independently of circulating PCs (PC<41 vs PC³41: OS=0% vs OS=16%, p=n.s.; PFS=0% vs 17%, p=n.s.). Patients with standard-risk cytogenetics (n=66) showed a better prognosis associated to a lower number of circulating PCs (PC<41 vs PC³41: OS=36% vs 10%, p=0.026; PFS=37% vs 0%, p=0.0001). These data were confirmed by multivariate analysis (Cox model) for the subgroup with standard-risk cytogenetics, in which the presence of ³41 circulating PCs, older age, DS stage >I and lack of maintenance therapy, adversely affected OS and PFS.
All patients with SP showed no circulating PCs. In all cases of MGUS or SM, circulating PCs, when detected, were <20.
In summary, our results suggest that the quantification of circulating PCs by flow cytometry could provide useful prognostic information in newly diagnosed MM patients with standard-risk cytogenetics.
Figure 1 Figure 1.
Figure 2 Figure 2.

Disclosures
No relevant conflicts of interest to declare.