References of "Baron, Frédéric"
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See detailL'Azacytidine comme traitement de la maladie du greffon contre l'hôte de type chronique sclérodermique expérimentale.
Fransolet, Gilles ULg; Ehx, Grégory ULg; SOMJA, Joan ULg et al

Conference (2015, November 19)

Introduction: Graft-versus-host disease (GVHD) has remained a major complication of allogeneic hematopoietic stem cell transplantation (HSCT) for the last decades. Following unmanipulated peripheral-blood ... [more ▼]

Introduction: Graft-versus-host disease (GVHD) has remained a major complication of allogeneic hematopoietic stem cell transplantation (HSCT) for the last decades. Following unmanipulated peripheral-blood stem cell transplantation, 60% of the patients experience chronic GVHD while approximately 15% of them develop a sclerodermic form of chronic GVHD characterized by multiple organ fibrosis and loss of skin elasticity. Regulatory T cells (Tregs) play a pivotal protective role in the pathogenesis of chronic GVHD by inhibiting alloreactive conventional T cells (Tconvs). Several studies have shown that hypomethylating agents such as azacytidine (Aza) can demethylate the master transcription factor of Treg (Forkhead box protein 3 factor, FoxP3), thus promoting Treg differentiation from Tconvs. This work investigates the impact of Aza in a classical murine model of sclerodermic chronic GVHD (B10.D2  BALB/cJ). Methods: In vitro analyses have been performed to determine the impact of Aza on collagen production. NIH-3T3 fibroblastic cells were plated and stimulated with 50 ng of PDGF or 10 ng of TGF-beta. Cells were then cultured with various concentrations of Aza for 48 hours. After culture, cells were stained with Sirius Red before quantification of collagen amount by absorbance at 490 nm. For in vivo experiments, lethally irradiated (7 Gy) BALB/cJ recipient mice were injected with 107 bone marrow cells + 7.107splenocytes from B10.D2 donor mice to induce scl-cGVHD. Recipients were injected with either 0,5 or 2 mg/kg of Aza every 48 hours from day 10 to 30 following transplantation. GVHD was scored using a five criteria scale (weight loss, activity, fibrosis, hair loss and mice posture; 0-1-2 points/criteria). Mice were sacrificed at a score of 8/10 (or > 20% weight loss) or at day 52 after transplantation (end of experiment). Results: Concerning in vitro analyses, results suggest a decreased production of collagen at higher concentration of Aza with both stimulations (seen by a gradual diminution of absorbance). For in vivo experiments, mice treated with Aza 0.5 mg/kg (n = 14) or 2 mg/kg (n = 25) had significant lower clinical scores of GVHD compared to control ones (n = 23) after treatment. FACS analysis showed a higher proportion of Treg among CD4+ T cells in the blood of Aza 2 mg/kg mice than in control mice at day 35 following transplantation (P = 0.047), as well as a higher percentage of Tregs expressing the KI67 proliferative marker on the same time point (P = 0.0005). Finally, analyses of the cellular blood components with Cell-dyn demonstrated that Aza 2 mg/kg treated mice were significantly lymphopenic as compared to control mice at day 35 after transplantation (P = 0.05). Conclusion : Aza prevented sclerodermic GVHD in this classical murine model of chronic GVHD. [less ▲]

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See detailPrediction of Allogeneic Hematopoietic Stem-Cell Transplantation Mortality 100 Days After Transplantation Using a Machine Learning Algorithm: A European Group for Blood and Marrow Transplantation Acute Leukemia Working Party Retrospective Data Mining Study
SHOUVAL, Roni; LABOPIN, Myriam; BONDI, Ori et al

in Journal of Clinical Oncology (2015), 33(28), 3144-3152

Purpose: Allogeneic hematopoietic stem-cell transplantation (HSCT) is potentiallu curative for acute leukemia (AL), but carries considerable risk. Machine learning algorithms, which are part of the data ... [more ▼]

Purpose: Allogeneic hematopoietic stem-cell transplantation (HSCT) is potentiallu curative for acute leukemia (AL), but carries considerable risk. Machine learning algorithms, which are part of the data mining (DM) approach, may serve for transplantation-related mortality risk prediction. Patients and Methods: This work is a retrospective DM study on a cohort of 28,236 adult HSCT recipients from the AL registry of the European Group for Blood and Marrow Transplantation. The primary objective was prediction of overall mortality (OM) at 100 days after HSCT. Secondary objectives were estimation of nonrelapse mortality, leukemia-free survival, and overall survival at 2 years. Donor, recipient, and procedural characteristics were alalyzed. The alternating decision tree machine learning algorithm was applied for model development on 70 % of the data set and validated on the remaining data. [less ▲]

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See detailOutcome and risk factor analysis of molecular subgroups in cytogenetically normal AML treated by allogeneic transplantation
SCHMID, Christoph; LABOPIN, Myriam; SOCIE, Gerard et al

in Blood (2015)

Patients with cytogenetically normal acute myeloid leukemia (CN-AML) can be subdivided by molecular mutations. However, data on the influence of combinations of different aberrations on outcome after ... [more ▼]

Patients with cytogenetically normal acute myeloid leukemia (CN-AML) can be subdivided by molecular mutations. However, data on the influence of combinations of different aberrations on outcome after allogeneic hematopoietic stem cell transplantation (HSCT) is limited. Therefore, we performed a retrospective registry analysis on 702 adults with CNAML undergoing HSCT in first complete remission (CR). Patients were grouped according to presence or absence of NPM1 mutations (NPM1mut) and FLT3 internal tandem duplications (FLT3-ITD). Double negative patients were evaluated for mutations of the CCAAT/enhancer binding protein α gene (CEBPα). The influence of genotypes on relapse, non-relapse mortality, leukemia-free survival (LFS) and overall survival (OS), and a prognostic classification combining NPM1/FLT3-ITD profile and classical risk factors were calculated. 2y-OS from HSCT was 81±5% in NPM1mut/FLT3wt (n=68), 75±3% in NPM1wt/FLT3wt (n=290), 66±3% in NPM1mut/FLT3-ITD (n=269) and 54±7% in NPM1wt/FLT3-ITD (n=75; p=0.003). Analysis of CEBPα among patients with NPM1wt/FLT3wt revealed excellent results both in patients with CEBPα mut (n=13, 2y-OS:100%), and with a triple negative genotype (n=138, 2y-OS:77±3%). In a Cox-model of predefined factors, older age, presence of FLT3-ITD and >1 course of chemotherapy to reach CR were associated with inferior outcome. 2y-OS/LFS were 88±3%/79±4% in patients without any, 77±2%/73±3% with one, and 53±4%/50±4 with>=2 risk factors (p=0.002 for LFS, p=0.003 for OS). Hence, FLT3-ITD proofed to be the decisive molecular marker for outcome after HSCT for CN-AML in CR1, regardless of NPM1 mutational status, variations of transplant protocols, or development of GvHD. Age, FLT3-ITD and response to induction chemotherapy allow for a prognostic risk classification. [less ▲]

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See detailImmune Recovery after Allogeneic Hematopoietic Stem Cell Transplantation following Flu-TBI versus TLI-ATG Conditioning
HANNON, Muriel ULg; BEGUIN, Yves ULg; Ehx, Grégory ULg et al

in Clinical Cancer Research : An Official Journal of the American Association for Cancer Research (2015), 21(14), 3131-9

Purpose: A conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) combining total lymphoid irradiation (TLI) plus anti-thymocyte globulin (ATG) has been develop to induce graft ... [more ▼]

Purpose: A conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) combining total lymphoid irradiation (TLI) plus anti-thymocyte globulin (ATG) has been develop to induce graft-versus-tumor effects without graft-versus-host disease (GVHD). Experimental Design: We compared immune recovery in 53 patients included in a phase II randomized study comparing nonmyeloablative HCT following either fludarabine plus 2 Gy total body irradiation (TBI arm, n=28) or 8 Gy TLI plus anti-thymocyte globulin (TLI arm, n=25). Results: In comparison to TBI patients, TLI patients had a similarly low 6-month incidence of grade II-IV acute GVHD, a lower incidence of moderate/severe chronic GVHD (P=0.02), a higher incidence of CMV reactivation (P<0.001), and a higher incidence of relapse (P=0.01). While recovery of total CD8+ T cells was similar in the two groups, with median CD8+ T cell counts reaching the normal values 40-60 days after allo-HCT, TLI patients had lower percentages of naïve CD8 T cells. Median CD4+ T cell counts did not reach the lower limit of normal values the first year after allo-HCT in the two groups. Further, CD4+ T cell counts were significantly lower in TLI than in TBI patients the first 6 months after transplantation. Interestingly, while median absolute regulatory T cell (Treg) counts were comparable in TBI and TLI patients, Treg/naïve CD4+ T cell ratios were significantly higher in TLI than in TBI patients the 2 first years after transplantation. Conclusions: Immune recovery differs substantially between these two conditioning regimens possibly explaining the different clinical outcomes observed (NCT00603954). [less ▲]

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See detailThe Sequence of Cyclophosphamide and Myeloablative Total Body Irradiation in Hematopoietic Cell Transplantation for Patients with Acute Leukemia
Holter-Chakrabarty, Jennifer; Pierson, Namali; Zhang, Mei-Jie et al

in Biology of Blood & Marrow Transplantation (2015), 21(7), 1251-7

Limited clinical data are available to assess whether the sequencing of cyclophosphamide (Cy) and total body irradiation (TBI) changes outcomes. We evaluated the sequence in 1769 (CyTBI, n ¼ 948; TBICy, n ... [more ▼]

Limited clinical data are available to assess whether the sequencing of cyclophosphamide (Cy) and total body irradiation (TBI) changes outcomes. We evaluated the sequence in 1769 (CyTBI, n ¼ 948; TBICy, n ¼ 821) recipients of related or unrelated hematopoietic cell transplantation who received TBI (1200 to 1500 cGY) for acute leukemia from 2003 to 2010. The 2 cohorts were comparable for median age, performance score, type of leukemia, first complete remission, Philadelphia chromosomeepositive acute lymphoblastic leukemia, HLAmatched siblings, stem cell source, antithymocyte globulin use, TBI dose, and type of graft-versus-host disease (GVHD) prophylaxis. The sequence of TBI did not significantly affect transplantation-related mortality (24% versus 23% at 3 years, P ¼.67; relative risk, 1.01; P ¼.91), leukemia relapse (27% versus 29% at 3 years, P ¼ .34; relative risk, .89, P ¼.18), leukemia-free survival (49% versus 48% at 3 years, P ¼.27; relative risk, .93; P ¼ .29), chronic GVHD (45% versus 47% at 1 year, P ¼.39; relative risk, .9; P ¼ .11), or overall survival (53% versus 52% at 3 years, P ¼.62; relative risk, .96; P ¼.57) for CyTBI and TBICy, respectively. Corresponding cumulative incidences of sinusoidal obstruction syndrome were 4% and 6% at 100 days (P ¼ .08), respectively. This study demonstrates that the sequence of Cy and TBI does not impact transplantation outcomes and complications in patients with acute leukemia undergoing hematopoietic cell transplantation with myeloablative conditioning. [less ▲]

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See detailExploring limiting factors in the prediction of allogeneic HSCT related mortality: an in-silico machine learning analysis of the acute leukemia working party (ALWP) registry of the EBMT
SHOUVAL, R.; LABOPIN, M.; UNGER, R. et al

in Bone Marrow Transplantation (2015, March), 50

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See detailAzacytidine prevents experimental sclerodermic chronic graft-versus-host disease
Fransolet, Gilles ULg; Ehx, Grégory ULg; SOMJA, Joan ULg et al

Poster (2015, January 30)

Introduction: Graft-versus-host disease (GVHD) remains one major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following unmanipulated peripheral-blood stem cell ... [more ▼]

Introduction: Graft-versus-host disease (GVHD) remains one major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Following unmanipulated peripheral-blood stem cell transplantation, 60% of the patients experience chronic GVHD while approximately 15% of them develop a sclerodermic form of chronic GVHD characterized by multiple organ fibrosis and loss of skin elasticity. Regulatory T cells (Tregs) play a pivotal role in the pathology of chronic GVHD by inhibiting alloreactive conventional T cells. Several studies have shown the hypomethylating agent Azacytidine (Aza) can demethylate the master transcription factor of Treg (Forkhead box protein 3 factor, FoxP3), thus promoting Treg differentiation of conventional T cells. This work investigates the impact of Aza in a classical murine model of sclerodermic chronic GVHD (B10.D2  BALB/cJ). Methods: Lethally irradiated BALB/cJ recipient mice were injected with 107 bone marrow cells + 7.107splenocytes from B10.D2 donor mice. Recipients were treated with subcutaneous injections of Aza at the dose of 0,5 or 2 mg/kg every two days from day 10 to 30 following transplantation. Mice GVHD was evaluated with five criteria (weight loss, activity, fibrosis, hair loss and mice posture; 0-1-2 points/criteria). Mice were sacrificed at a score of 8/10 (or > 20% weight loss). Results: Mice treated with Aza 0.5 mg/kg (n = 14) or 2 mg/kg (n = 17) had significant lower clinical scores compared to control ones (n = 15) after treatment. FACS analysis showed a higher proportion of Treg among CD4+ T cells in the blood of Aza 2 mg/kg mice than in control mice (P = 0.047), as well as a higher percentage of Tregs expressing the KI67 proliferative marker on the same day (P = 0.0005). Finally, analyses of the cellular blood components with Cell-dyn demonstrated that Aza 2 mg/kg treated mice were significantly lymphopenic as compared to control mice (P = 0.05). Conclusion : Aza prevented sclerodermic GVHD in this classical murine model of chronic GVHD. [less ▲]

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See detailValidation of a multicolor staining to monitor phosphoSTAT5 levels in regulatory T-cell subsets
Ehx, Grégory ULg; Hannon, Muriel ULg; BEGUIN, Yves ULg et al

in Oncotarget (2015)

BACKGROUND: Regulatory T cells (Tregs) are key players in immune tolerance. They express the transcription factor FOXP3 and are dependent of the STAT5 signaling for their homeostasis. So far, the study of ... [more ▼]

BACKGROUND: Regulatory T cells (Tregs) are key players in immune tolerance. They express the transcription factor FOXP3 and are dependent of the STAT5 signaling for their homeostasis. So far, the study of phosphorylated epitopes by flow cytometry required treating the cells with methanol, which is harmful for several epitopes. METHODS: Here we assessed whether the PerFix EXPOSE reagent kit (PFE) (Beckman Coulter) allowed monitoring the phosphorylation level of STAT5 in Treg subpopulations together with complex immunophenotyping. Results observed with the PFE kit were compared to those observed without cell permeabilization for surface markers, with paraformaldehyde permeabilization for non-phosphorylated intracellular epitopes, and with methanol-based permeabilization for phosphoSTAT5 staining. RESULTS: In human PBMCs, the PFE kit allowed the detection of surface antigens, FOXP3, KI67 and phosphoSTAT5 in similar proportions to what was observed without permeabilization (for surface antigens), or with PFA or methanol permeabilizations for FOXP3/KI67 and phosphoSTAT5, respectively. Comparable observations were made with murine splenocytes. Further, the PFE kit allowed determining the response of different human and murine Treg subsets to IL-2. It also allowed demonstrating that human Treg subsets with the highest levels of phosphoSTAT5 had also the highest suppressive activity in vitro, and that anti-thymocyte glogulin (ATG) induced Treg independently of the STAT5 pathway, both in vitro and in vivo. CONCLUSIONS: We have validated a multicolor staining method that allows monitoring phosphoSTAT5 levels in Treg subsets. This staining could be useful to monitor responses of various Treg subsets to IL-2 therapy. [less ▲]

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See detailMonoclonal antibodies against GARP/TGF-b1 complexes inhibit the immunosuppressive activity of human regulatory T cells in vivo
Cuende, Julia; Liénart, Stéphanie; Dedobbeleer, Olivier et al

in Science Translational Medicine (2015), 7(284), 1-12

Regulatory T cells (Tregs) are essential to prevent autoimmunity, but excessive Treg function contributes to cancer progression by inhibiting antitumor immune responses. Tregs exert contact-dependent ... [more ▼]

Regulatory T cells (Tregs) are essential to prevent autoimmunity, but excessive Treg function contributes to cancer progression by inhibiting antitumor immune responses. Tregs exert contact-dependent inhibition of immune cells through the production of active transforming growth factor–b1 (TGF-b1). On the Treg cell surface, TGF-b1 is in an inactive form bound to membrane protein GARP and then activated by an unknown mechanism. We demonstrate that GARP is involved in this activation mechanism. Two anti-GARP monoclonal antibodies were generated that block the production of active TGF-b1 by human Tregs. These antibodies recognize a conformational epitope that requires amino acids GARP137–139 within GARP/TGF-b1 complexes. A variety of antibodies recognizing other GARP epitopes did not block active TGF-b1 production by Tregs. In a model of xenogeneic graft-versus-host disease in NSG mice, the blocking antibodies inhibited the immunosuppressive activity of human Tregs. These antibodies may serve as therapeutic tools to boost immune responses to infection or cancer via a mechanism of action distinct from that of currently available immunomodulatory antibodies. Used alone or in combination with tumor vaccines or antibodies targeting the CTLA4 or PD1/PD-L1 pathways, blocking anti-GARP antibodies may improve the efficiency of cancer immunotherapy. [less ▲]

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See detailImpact of graft source and composition on outcomes after allogeneic stem cell transplantation
SERVAIS, Sophie ULg; Baron, Frédéric ULg; BEGUIN, Yves ULg

in Belgian Journal of Hematology (2015), 6(4), 162-168

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See detailDecitabine versus best supportive care in older patients with refractory anemia with excess blasts in transformation (RAEBt) - results of a subgroup analysis of the randomized phase III study 06011 of the EORTC Leukemia Cooperative Group and German MDS Study Group (GMDSSG)
BECKER, Heiko; SUCIU, Stefan; RUTER, Björn Hans et al

in Annals of Hematology (2015), 94

In the European Organisation for Research and Treatment of Cancer (EORTC)/GMDSSG phase III trial06011, we compared decitabine (15 mg/m² every 8 h for 3 days) with best supportive care (BSC) in patients ... [more ▼]

In the European Organisation for Research and Treatment of Cancer (EORTC)/GMDSSG phase III trial06011, we compared decitabine (15 mg/m² every 8 h for 3 days) with best supportive care (BSC) in patients >/= 60 years with myelodysplastic syndromes (MDS) by French-Amercian-British (FAB) criteria. Here, we reinvestigate trial 06011 for the activity and efficacy specifically in patients with refractory anemia with excess blasts in transformation (RAEBt). Response rates in the decitabine arm (N=40) were as follow: complete or partial remission, 15 %; hematologic improvement, 15 %; resistant disease, 30 %. RAEBt patients in the decitabine arm had longer progression-free survival (PFS; hazard ratio (HR) 0.30, 95 % confidence interval (CI) 0.18-0.51; median, 6.2 vs 2.8 months) and overall survival (OS; HR 0.68, 95 % CI 0.42-1.11; median, 8.0 vs 6.0 months) than in the BSC arm (N=35). Censoring at allogeneic hematopoietic stem cell transplantation, the OS difference between the treatment groups increased, particularly among patients. [less ▲]

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See detailUnrelated cord blood transplantation for adult patients with acute myeloid leukemia: Higher incidence of acute graft-versus-host disease and lower survival in male patients transplanted with female unrelated cord blood-a report from Eurocord, the Acute Leukemia Working Party, and the Cord Blood Committee of the Cellular Therapy and Immunobiology Working Party of the European Group for Blood and Marrow Transplantation
BARON, Frédéric ULg; LABOPIN, Myriam; RUGGERI, Annalisa et al

in Journal of Hematology & Oncology (2015), 8

Background: In the setting of allogeneic human leukocyte antigen (HLA)-matched bone marrow transplantation, transplanting male patients with grafts from female donors has been associated with a higher ... [more ▼]

Background: In the setting of allogeneic human leukocyte antigen (HLA)-matched bone marrow transplantation, transplanting male patients with grafts from female donors has been associated with a higher incidence of graft-versus-host disease (GVHD) and of nonrelapse mortality (NRM). The aim of the current analysis was to compare transplantation outcomes in male patients given female unrelated cord blood (UCB) versus other gender combinations. Patients and methods: Data from 552 consecutive patients with acute myeloid leukemia (AML) given a single UCB transplantation between 2000 and 2014 were included. Results: In comparison with other gender combination, male patients given female UCB (n = 131) had a trend for a higher incidence of grades II–IV acute GVHD (33 versus 25 %, P = 0.08), a trend for a higher incidence of NRM (41 versus 33 %, P = 0.06), and a lower leukemia-free (LFS, 30 versus 41 %, P = 0.01) and overall survival (OS, 33 versus 45 %, P = 0.008). In multivariate analyses, taking into consideration all patients for which data on HLA-matching and cell dose transplanted were fully available (n = 363), male patients transplanted with a female UCB had a trend for a higher incidence of grade III–IV acute GVHD (hazard ratio (HR) = 2.0, P = 0.06), a trend for a higher NRM (HR = 1.5, P = 0.06), and a worse LFS (HR = 1.4, P = 0.04) and OS (HR = 1.3, P = 0.06). Conclusions: Our data suggest that male patients transplanted with female UCB might have higher risk of acute GVHD and of NRM leading to worse LFS and OS. These results should be confirmed in other large cohorts of patients before used for determining the choice of an UCB unit. [less ▲]

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