Implication des lymphocytes T régulateurs dans les traitements cibés de la polyarthrite rhumatoïde

Les médiateurs de l inflammation ont un rôle central dans l immuno-pathogénèse de la polyarthrite rhumatoïde (PR), la preuve étant le succès des traitements ciblant les cytokines telles que l interleukine (IL-6). Les lymphocytes T régulateurs (Tregs) ont pour fonction le maintien de la tolérance et sont en déficit fonctionnel dans cette pathologie. De nombreuses cytokines participent à la régulation des Tregs. Ainsi, l IL-6 joue u rôle central dans l immuno-pathogénèse de la PR notamment par son action sur le développement périphérique des Tregs. Récemment l interleukine (IL)-35 a été définie comme une cytokine exclusivement secrétée par les Tregs et serait donc impliquée dans les fonctions régulatrices des Tregs humains et murins. L objectif de ce travail de thèse était d évaluer le rôle des Tregs dans les mécanismes d action des traitements ciblés dans la PR et l un de ces modèles. Tout d abord nous avons souhaité mieux définir la contribution des Tregs dans les traitements ciblant le récepteur de l IL-6 dans la PR et l arthrite expérimentale au collagène (AEC). Dans ce travail, nous avons démontré pour la première fois que le traitement par un anticorps ciblant le récepteur de l IL-6, chez les patients atteints de PR ou chez les souris arthritiques, stimule les Tregs CD39 . Au regard de cette première étude, cette population cellulaire se présente comme une cible thérapeutique intéressante. En second lieu nous avons étudié les propriétés biologiques de l IL-35 et son rôle sur les Tregs dans l AEC ; Afin d évaluer ses effets biologiques, nous avions administré l IL-35 par électrotransfert de plasmides codant son gène dans l AEC. L ensemble de cette étude apporte un regard nouveau sur l IL-35 puisque nous montrons pour la première fois un rôle délétère de l IL-35 da,s l AEC. Bien que nous ne puissions pas exclure que ce rôle délétère ne soit pas la résultante d un effet synergique de l électrotransfert, notre étude suscite des interrogations quant à son utilisation thérapeutique.PARIS13-BU Sciences (930792102) / SudocSudocFranceF

Belatacept inhibit human B cell germinal center development in immunodeficient mice

Abstract The humoral response mediated by alloantibodies directed against donor HLA molecules (DSAs) is one of the main causes of graft loss in kidney transplantation. Understanding the pathophysiology leading to humoral kidney rejection as the development of therapeutic tools is therefore a main objective in the field of solid organ transplantation and necessitate adapted experimental models. Among the immunosuppressive agents used in renal transplantation, belatacept, a fusion protein targeting T costimulatory molecules has shown its ability to prevent more efficiently the secretion of DSA by different mechanisms including a direct action on plasma cells but also on B lymphocytes and follicular helper T lymphocytes (Tfh) cooperation. This cellular cooperation occurs within germinal centers (GC), the seat of B lymphocytes differentiation. Here, we aimed to develop a dedicated mouse model in which human GC would be functional to study the effect of belatacept on GC formation and the ability of B lymphocytes to secrete immunoglobulin. We next demonstrate that belatacept inhibits the formation of these GCs, by inhibiting the frequency of Tfh and B lymphocytes. This alters the B maturation and therefore the generation of plasma cells and consequently, immunoglobulin secretion

Intra-articular electrotransfer of mouse soluble tumour necrosis factor receptor in a murine model of rheumatoid arthritis

Background Rheumatoid arthritis (RA) is a chronic autoimmune diseasethat causes inflammation and destruction of the joints. In the collagen-induced arthritis mouse model of RA, we developed a nonviral gene therapymethod designed to block in situ the main cytokine tumour necrosis factor(TNF)-αMethods Electrotransfer was used to deliver a plasmid encoding extracellu-lar domain of mouse soluble TNF-α receptor type I fused to the Fc fragment ofmouse immunoglobulin (Ig)G1 (pTNFR-Is) corresponding to a dimeric TNF-αsoluble receptor fusion protein (mTNFR-Is/Ig).Results Delivery of the plasmid into the knees at symptom onset improvedthe histological inflammation and destruction not only at the knees, but alsoat the ankles, indicating a local and a regional therapeutic effect. The p lasmidwas detected in synovial membrane and meniscus specimens from the injectedjoints. In the synovial membrane, 15 days post-injection, interleukin (IL)-17and TNF-α mRNAs expression were increased, whereas IL-10 mRNA wasunchanged. However, the empty plasmid exerted a pro-inflammatory effect30 days post-injection.Conclusions These data indicate that local nonviral gene therapy againstTNF-α is effective, although further work is needed to decrease plasmidinduced inflammation

Simple, Reproducible, and Efficient Clinical Grading System for Murine Models of Acute Graft-versus-Host Disease

Acute graft-versus-host disease (aGVHD) represents a challenging complication after allogeneic hematopoietic stem cell transplantation. Despite the intensive preclinical research in the field of prevention and treatment of aGVHD, and the presence of a well-established clinical grading system to evaluate human aGVHD, such a valid tool is still lacking for the evaluation of murine aGVHD. Indeed, several scoring systems have been reported, but none of them has been properly evaluated and they all share some limitations: they incompletely reflect the disease, rely on severity stages that are distinguished by subjective assessment of clinical criteria and are not easy to discriminate, which could render evaluation more time consuming, and their reproducibility among different experimenters is uncertain. Consequently, clinical murine aGVHD description is often based merely on animal weight loss and mortality. Here, we propose a simple scoring system of aGVHD relying on the binary (yes or no) evaluation of five important visual parameters that reflect the complexity of the disease without the need to sacrifice the mice. We show that this scoring system is consistent with the gold standard histological staging of aGVHD across several donor/recipient mice combinations. This system is also a strong predictor of survival of recipient mice when used early after transplant and is highly reproducible between experimenters

Simple, Reproducible, and Efficient Clinical Grading System for Murine Models of Acute Graft-versus-Host Disease

International audienceAcute graft-versus-host disease (aGVHD) represents a challenging complication after allogeneic hematopoietic stem cell transplantation. Despite the intensive preclinical research in the field of prevention and treatment of aGVHD, and the presence of a well-established clinical grading system to evaluate human aGVHD, such a valid tool is still lacking for the evaluation of murine aGVHD. Indeed, several scoring systems have been reported, but none of them has been properly evaluated and they all share some limitations: they incompletely reflect the disease, rely on severity stages that are distinguished by subjective assessment of clinical criteria and are not easy to discriminate, which could render evaluation more time consuming, and their reproducibility among different experimenters is uncertain. Consequently, clinical murine aGVHD description is often based merely on animal weight loss and mortality. Here, we propose a simple scoring system of aGVHD relying on the binary (yes or no) evaluation of five important visual parameters that reflect the complexity of the disease without the need to sacrifice the mice. We show that this scoring system is consistent with the gold standard histological staging of aGVHD across several donor/recipient mice combinations. This system is also a strong predictor of survival of recipient mice when used early after transplant and is highly reproducible between experimenters

Pathologic Response to Neoadjuvant Sequential Chemoradiation Therapy in Locally Advanced Breast Cancer: Preliminary, Translational Results from the French Neo-APBI-01 Trial

Background: Radiation therapy (RT), a novel approach to boost the anticancer immune response, has been progressively evaluated in the neoadjuvant setting in breast cancer (BC). Purpose: We aimed to evaluate immunity-related indicators of response to neoadjuvant chemoradiation therapy (NACRT) in BC for better treatment personalization. Patients and Methods: We analyzed data of the first 42 patients included in the randomized phase 2 Neo-APBI-01 trial comparing standard neoadjuvant chemotherapy (NACT) and NACRT regimen in locally advanced triple-negative (TN) and luminal B (LB) subtype BC. Clinicopathological parameters, blood counts and the derived parameters, total tumor-infiltrating lymphocytes (TILs) and their subpopulation, as well as TP53 mutation status, were assessed as predictors of response. Results: Twenty-one patients were equally assigned to each group. The pathologic complete response (pCR) was 33% and 38% in the NACT and NACRT groups, respectively, with a dose-response effect. Only one LB tumor reached pCR after NACRT. Numerous parameters associated with response were identified, which differed according to the assigned treatment. In the NACRT group, baseline hemoglobin of ≥13 g/dL and body mass index of <26 were strongly associated with pCR. Higher baseline neutrophils-to-lymphocytes ratio, total TILs, and T-effector cell counts were favorable for pCR. Conclusion: This preliminary analysis identified LB and low-TIL tumors as poor responders to the NACRT protocol, which delivered RT after several cycles of chemotherapy. These findings will allow for amending the selection of patients for the trial and help better design future trials of NACRT in BC

Human Apoptotic Cells, Generated by Extracorporeal Photopheresis, Modulate Allogeneic Immune Response

International audienceThe induction of specific and sustainable tolerance is a challenging issue in organ transplantation. The discovery of the immunosuppressive properties of apoptotic cells in animal models has paved the way for their use in human transplantation. In this work, we aimed to define a stable, reproducible, and clinically compatible production procedure of human apoptotic cells (Apo-cells). Using a clinically approved extracorporeal photopheresis technique, we have produced and characterized phenotypically and functionally human apoptotic cells. These Apo-cells have immunosuppressive properties proved in vitro and in vivo in NOD/SCID/γC mice by their capacity to modulate an allogeneic response following both a direct and an indirect antigen presentation. These results brought the rationale for the use of Apo-cells in tolerance induction protocol for organ transplantation

In Vivo Expansion of Activated Foxp3 + Regulatory T Cells and Establishment of a Type 2 Immune Response upon IL-33 Treatment Protect against Experimental Arthritis

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