References of "Hannon, Muriel"
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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 (in press)

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 detailEtude de la reconstitution immunitaire après greffe de cellules souches hématopoïétiques : focus sur la fonction thymique et les lymphocytes T régulateurs
HANNON, Muriel ULg

Doctoral thesis (2015)

L’allogre e de cellules souches hématopoïétiques, après conditionnement myéloalbatif ou non, est devenue une option de choix dans le traitement des maladies hématologiques malignes ou génétiques ... [more ▼]

L’allogre e de cellules souches hématopoïétiques, après conditionnement myéloalbatif ou non, est devenue une option de choix dans le traitement des maladies hématologiques malignes ou génétiques. Malheureusement le succès de ce traitement se trouve trop souvent entaché par des complications majeures telles que les infections ou la maladie du greffon contre l’hôte (GVHD), dans laquelle les cellules du donneur attaquent l’organisme du receveur. La reconstitution d’un système immunitaire fonctionnel, notamment via le thymus, est une étape clef dans la résolution de ces deux complications et l’utilisation de lymphocytes T régulateurs semble très prometteuse dans la lutte contre la GVHD. Le présent travail vise donc à étudier la reconstitution du système immunitaire après allogreffe sous trois angles différents, en nous focalisant sur la fonction thymique et l’influence des lymphocytes T régulateurs (Treg). Dans la première partie, nous évaluons la reconstitution immunitaire à long terme après greffe non-myéloablative et montrons que la néo-génération de lymphocytes T par le thymus s’effectue à partir du jour 100 chez les patients de moins de 60 ans alors qu’au delà de cet âge, elle est quasiment absente. Nous établissons également que la GVHD chronique (cGVHD) sévère possède des effets extrêmement délétères sur le thymus. Étant donné l’impact de la cGVHD sur le thymus et la reconstitution immunitaire, nous avons voulu comparer l’impact, sur ces deux paramètres, d’un conditionnement nonmyéloalbatif censé réduire la GVHD et composé d’une irradiation lymphoïde totale et d’anticorps anti-thymocytes (TLI-ATG) par rapport au conditionnement classique consistant en une irradiation corporelle totale associée à de la fludarabine (TBI-Flu). Il ressort de cette étude que, bien que réduisant de manière significative l’incidence de cGVHD, le conditionnement TLI-ATG altère fortement la reconstitution du système immunitaire et impacte négativement le taux de rechute/progression chez les patients traités. Enfin, toujours dans le but de réduire le taux de GVHD post-greffe, nous avons choisi d’examiner l’impact des Treg comme traitement de la xGVHD. Dans ce but, nous montrons qu’une sélection de Treg humains, sur CliniMACS par déplétion CD8/19 et sélection CD25, fournit une population de cellules enrichies en Treg capable de retarder de manière statistiquement significative l’apparition d’une GVHD xénogénique induite par injection de PBMC humains (autologues aux Treg) dans un modèle pré-clinique chez la souris NSG. De plus, lorsque injectée sans les PBMC, cette population enrichie n’induit pas par elle-même de GHVD. [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)

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 detailInfusion of clinical-grade enriched regulatory T cells delays experimental xenogeneic graft-versus-host disease
Hannon, Muriel ULg; LECHANTEUR, Chantal ULg; Lucas, Sophie et al

in Transfusion (2014), 54(February), 353-363

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See detailImmunomodulatory effects of Rapamycin in xenogeneic GVHD
Ehx, Grégory ULg; HANNON, Muriel ULg; DUBOIS, Sophie ULg et al

Poster (2014, January 27)

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See detailEstablishment of a murine graft-versus-myeloma model using allogeneic stem cell transplantation
Binsfeld, Marilène ULg; Beguin, Yves ULg; Belle, Ludovic et al

in PLoS ONE (2014), (doi:10.1371), 113764

Background: Multiple myeloma (MM) is a malignant plasma cell disorder with poor long-term survival and high recurrence rates. Despite evidence of graft-versus-myeloma (GvM) effects, the use of allogeneic ... [more ▼]

Background: Multiple myeloma (MM) is a malignant plasma cell disorder with poor long-term survival and high recurrence rates. Despite evidence of graft-versus-myeloma (GvM) effects, the use of allogeneic hematopoietic stem cell transplantation (allo-SCT) has remained controversial in MM. In the current study, we investigated the anti-myeloma effects of allo-SCT from B10.D2 mice into MHC-matched myeloma-bearing Balb/cJ mice (previously injected with the MOPC315.BM myeloma cell line), based on a chronic graft-versus-host disease (GvHD) murine model. Methods and results: Balb/cJ mice were injected intravenously with luciferase-transfected MOPC315.BM cells, and received 30 days later an allogeneic (B10.D2 donor) or autologous (Balb/cJ donor) transplantation by intravenous administration of bone marrow cells and splenocytes. We observed a graft-versus-myeloma effect in 94% of the allogeneic transplanted mice, as luciferase signal completely disappeared after transplantation, whereas all the autologous transplanted mice showed myeloma evolution. Lower serum paraprotein levels and myeloma infiltration in bone marrow and spleen in the allogeneic setting confirmed the observed GvM effect, while allogeneic mice also displayed chronic GvHD symptoms. In vivo and in vitro data suggest the involvement of effector memory CD4 and CD8 T cells in the GvM effect. The essential role of CD8 T cells was demonstrated in vivo where CD8 T-cell depletion of the graft resulted in reduced GvM effects. Finally, TCR V spectratyping analysis identified V families within CD4 and CD8 T cells which were associated with both GvM effects and GVHD, whereas other V families within CD4 T cells were associated exclusively with either GvM or GvHD responses. Conclusions: We successfully established an immunocompetent murine model of graft-versus-myeloma. This is the first immunocompetent murine model which is based on a MM model closely resembling human MM disease (bone marrow tropism, ...) and using allo-SCT after the disease establishment, as a curative treatment [less ▲]

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See detailThinking out of the box - New approaches to controlling GVHD
Baron, Frédéric ULg; Humblet-Baron, Stéphanie; Ehx, Grégory ULg et al

in Current Hematologic Malignancy Reports (2014), 9

Graft-versus-host disease (GVHD) remains a major limitation of allogeneic hematopoietic cell transplantation (allo-HCT). Despite major advances in the understanding of GVHD pathogenesis, standard GVHD ... [more ▼]

Graft-versus-host disease (GVHD) remains a major limitation of allogeneic hematopoietic cell transplantation (allo-HCT). Despite major advances in the understanding of GVHD pathogenesis, standard GVHD prophylaxis regimens continue to bebased on the combination of a calcineurin inhibitor with an antimetabolite, while first line treatmentsstill relies on high-dose corticosteroids. Further, no second line treatment has emerged thus far in acute or chronic GVHD patients who failed on corticosteroids. After briefly reviewing current standards of GVHD prevention and treatment, this article will discuss recent approaches that might change GVHD prophylaxis / treatment in the next decades, with a special focus on recently developed immunoregulatory strategies based on infusion of mesenchymal stromal or regulatory T-cells, or on injection of lowdose interleukin-2. [less ▲]

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See detailEstablishment of a murine graft-versus-myeloma model using allogeneic stem cell transplantation.
Binsfeld, Marilène ULg; BEGUIN, Yves ULg; Belle, Ludovic et al

in Belgian Journal of Hematology (2014)

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See detailImpact of bone marrow-derived mesenchymal stromal cells on experimental xenogeneic graft-versus-host disease
Bruck, France; Belle, Ludovic ULg; LECHANTEUR, Chantal ULg et al

in Cytotherapy (2013), 15(3), 267-279

Background aims. Graft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation caused by donor T cells reacting against host tissues. Previous ... [more ▼]

Background aims. Graft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation caused by donor T cells reacting against host tissues. Previous studies have suggested that mesenchymal stromal cells (MSCs) could exert potent immunosuppressive effects. Methods. The ability of human bone marrow derived MSCs to prevent xenogeneic GVHD in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice and in NOD/SCID/interleukin-2Rg(null) (NSG) mice transplanted with human peripheral blood mononuclear cells (PBMCs) was assessed. Results. Injection of 200 106 human PBMCs intraperitoneally (IP) into sub-lethally (3.0 Gy) irradiated NOD/SCID mice also given anti-asialo GM1 antibodies IP 1 day prior and 8 days after transplantation induced lethal xenogeneic GVHD in all tested mice. Co-injection of 2 106 MSCs IP on day 0 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs. Similarly, injection of 30 106 human PBMCs IP into sub-lethally (2.5 Gy) irradiated NSG mice induced a lethal xenogeneic GVHD in all tested mice. Injection of 3 106 MSCs IP on days 0, 7, 14 and 21 did not prevent lethal xenogeneic GVHD induced by injection of human PBMCs. Conclusions. Injection of MSCs did not prevent xenogeneic GVHD in these two humanized mice models. [less ▲]

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See detailComparison of Immune Reconstitution after Hematopoietic Stem Cell Transplantation with Flu-TBI versus TLI-ATG Conditioning
Hannon, Muriel ULg; Humblet-Baron, S.; Graux, C. et al

in Belgian Journal of Hematology (2013), Abstracts book(Supplement of 28th General Meeting of the Belgian Hematological Society), 38

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See detailInfusion of CliniMACS (Myltenyi Biotec) Enriched Regulatory T Cells Delays Experimental Xenogeneic Graft-versus-Host Disease
Hannon, Muriel ULg; Lechanteur, C.; Somja, Joan ULg et al

in Belgian Journal of Hematology (2013), Abstracts book(Supplement of 28th General Meeting of the Belgian Hematological Society), 15

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See detailThe Immunomodulating Peptide Thymosin Alpha 1 Has no Effect on Multiple Myeloma Evolution and on Immune Reconstitution
Binsfeld, Marilène ULg; Otjacques, Eléonore ULg; Hannon, Muriel ULg et al

in Belgian Journal of Hematology (2013), Abstracts book(Supplement of 28th General Meeting of the Belgian Hematological Society), 41

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See detailKinetics of IL-7 and IL-15 Levels after Allogeneic Peripheral Blood Stem Cell Transplantation following Nonmyeloablative Conditioning
De Bock, Muriel; Fillet, Marianne ULg; Hannon, Muriel ULg et al

in PLoS ONE (2013), 8(2), 55876

Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were ... [more ▼]

Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were obtained before conditioning and about once per week after transplantation until day 100. Samples were aliquoted and stored at 280uC within 3 hours after collection until measurement of cytokines. IL-7 and IL-15 levels were measured by ELISAs. Results: Median IL-7 plasma levels remained below 6 pg/L throughout the first 100 days, although IL-7 plasma levels were significantly higher on days 7 (5.1 pg/mL, P = 0.002), 14 (5.2 pg/mL, P,0.001), and 28 (5.1 pg/mL, P = 0.03) (but not thereafter) than before transplantation (median value of 3.8 pg/mL). Median IL-15 serum levels were significantly higher on days 7 (12.5 pg/mL, P,0.001), 14 (10.5 pg/mL, P,0.001), and 28 (6.2 pg/mL, P,0.001) than before transplantation (median value of 2.4 pg/mL). Importantly, IL-7 and IL-15 levels on days 7 or 14 after transplantation did not predict grade II–IV acute GVHD. Conclusions: These data suggest that IL-7 and IL-15 levels remain relatively low after nonmyeloablative transplantation, and that IL-7 and IL-15 levels early after nonmyeloablative transplantation do not predict for acute GVHD. [less ▲]

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See detailRapamycin Prevents Experimental Sclerodermatous Chronic Graft-versus-Host Disease in mice
Belle, Ludovic ULg; Binsfeld, Marilène ULg; DUBOIS, Sophie ULg et al

in Belgian Journal of Hematology (2012), Abstracts book(Supplement of 27th General Meeting of the Belgian Hematological Society), 14

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