Prise en charge chirurgicale des nævi géants congénitaux (définition d un algorithme)

Le nævus géant congénital (NGC) est une pathologie rare. Le risque de transformation maligne existe et son aspect parfois très inesthétique oblige à une prise en charge chirurgicale précoce. Celle-ci est différente suivant la localisation du nævus et toutes les techniques de chirurgie plastique doivent être utilisées au mieux. L expansion cutanée est la technique la plus utilisée pour le cuir chevelu, la face et le tronc. L exérèse itérative et l utilisation de derme artificiel (Intégra®) restent les techniques de choix pour les membres inférieurs et supérieurs. Nous rapportons l expérience du service à partir de 104 dossiers et nous définissons un algorithme pour chaque localisation. La gestion du capital de peau saine est parfois un vrai défi chirurgical.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Cell therapy with engineered HLA-A2 specific CAR-CD8+Tregs to avoid transplant rejection

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Human CD8+ Tregs expressing a MHC-specific CAR display enhanced suppression of human skin rejection and GVHD in NSG mice

International audiencePolyclonal CD8+CD45RClow/- Tregs are potent regulatory cells able to control solid organ transplantation rejection and even induce tolerance. However, donor major histocompatibility complex (MHC)-specific Tregs are more potent than polyclonal Tregs in suppressing T-cell responses and preventing acute as well as chronic rejection in rodent models. The difficulty of identifying disease-relevant antigens able to stimulate Tregs has reduced the possibility of obtaining antigen-specific Tregs. To bypass this requirement and gain the advantage of antigen specificity, and thus improve the therapeutic potential of CD8+ Tregs, we stably introduced a chimeric antigen receptor (CAR) derived from a HLA-A*02 antigen-specific antibody (A2-CAR) in human CD8+ Tregs and developed a clinically compatible protocol of transduction and expansion. We demonstrated that A2-CAR CD8+ Tregs were not phenotypically altered by the process, were specifically activated, and did not exhibit cytotoxic activity toward HLA-A*02+ kidney endothelial cells (ECs). We showed that A2-CAR CD8+ Tregs were more potent suppressors of immune responses induced by HLA-A*02 mismatch than control-CAR CD8+ Tregs, both in vitro and in vivo, in models of human skin graft rejection and graft-versus-host disease (GVHD) in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. We showed that integrity of human skin graft was preserved with A2-CAR CD8+ Tregs at least 100 days in vivo after administration, and that interaction between the A2-CAR CD8+ Tregs and HLA-A*02+ kidney ECs resulted in a fine-tuned and protolerogenic activation of the ECs without cytotoxicity. Together, our results demonstrated the relevance of the CAR engineering approach to develop antigen-specific CAR-CD8+ Tregs for clinical trials in transplantation, and potentially in other diseases

Expanded human CD8+CD45RClowFoxp3+ Tregs secreting IFNγ, IL-10, IL-34 and TGFβinhibit human transplant rejection

International audienceTregs play a critical role in the control of immune responses and tolerance induction; however our understanding of CD8+ Tregs is limited while they are particularly promising for therapeutic application. We previously reported that CD8+CD45RC[low] Tregs use IFNγ and IL-34 to suppress donor responses in a rat model of allotransplantation (Guillonneau et al, JCI, 2007 ; Bezieetal, JCI, 2015). Here, we aim to characterize human CD8+ Tregs to assess their potential for cell therapy in transplantation in comparison to CD4+CD25[high]CD127- Tregs

Expanded human CD8+CD45RClowFoxp3+ Tregs secreting IFNγ, IL-10, IL-34 and TGFβinhibit human transplant rejection

International audienceTregs play a critical role in the control of immune responses and tolerance induction; however our understanding of CD8+ Tregs is limited while they are particularly promising for therapeutic application. We previously reported that CD8+CD45RC[low] Tregs use IFNγ and IL-34 to suppress donor responses in a rat model of allotransplantation (Guillonneau et al, JCI, 2007 ; Bezieetal, JCI, 2015). Here, we aim to characterize human CD8+ Tregs to assess their potential for cell therapy in transplantation in comparison to CD4+CD25[high]CD127- Tregs

Expansion of natural CD8+Tregs for cell therapy

International audienceTregs play a critical role in the control of immune responses and tolerance induction; however our understanding of CD8+ Tregs is limited while they are particularly promising for therapeutic application. We previously reported that CD8+CD45RC[low] Tregs use IFNγ and IL-34 to suppress donor responses in a rat model of allotransplantation (Guillonneau et al, JCI, 2007; Bezie et al, JCI, 2015). Here, we aim to characterize human CD8+ Tregs to assess their potential for cell therapy in transplantation

Ex Vivo Expanded Human Non-Cytotoxic CD8+CD45RClow/-Tregs Efficiently Delay Skin Graft Rejection and GVHD in Humanized Mice

International audienceBoth CD4+and CD8+Tregs play a critical role in the control of immune responses and immune tolerance; however, our understanding of CD8+Tregs is limited while they are particularly promising for therapeutic application. We report here existence of highly suppressive human CD8+CD45RClow/-Tregs expressing Foxp3 and producing IFNγ, IL-10, IL-34, and TGFβ to mediate their suppressive activity. We demonstrate that total CD8+CD45RClow/-Tregs can be efficiently expanded in the presence of anti-CD3/28 mAbs, high-dose IL-2 and IL-15 and that such expanded Tregs efficiently delay GVHD and human skin transplantation rejection in immune humanized mice. Robustly expanded CD8+Tregs displayed a specific gene signature, upregulated cytokines and expansion in the presence of rapamycin greatly improved proliferation and suppression. We show that CD8+CD45RClow/-Tregs are equivalent to canonical CD4+CD25highCD127low/-Tregs for suppression of allogeneic immune responsesin vitro. Altogether, our results open new perspectives to tolerogenic strategies in human solid organ transplantation and GVHD

Functional Langerin high -Expressing Langerhans-like Cells Can Arise from CD14 high CD16 − Human Blood Monocytes in Serum-Free Condition

International audienceLangerhans cells (LCs) are epithelial APCs that sense danger signals and in turn trigger specific immune responses. In steady-state, they participate in the maintenance of peripheral tolerance to self-antigens whereas under inflammation LCs efficiently trigger immune responses in secondary lymphoid organs. It has been demonstrated in mice that LC-deprived epithelia are rapidly replenished by short half-life langerin-expressing monocyte-derived LCs (MDLCs). These surrogate LCs are thought to be progressively replaced by langerinhigh LCs arising from self-renewing epithelial precursors of hematopoietic origin. How LCs arise from blood monocytes is not fully understood. Hence, we sought to characterize key factors that induce differentiation of langerinhigh-expressing monocyte-derived Langerhans-like cells. We identified GM-CSF and TGF-b1 as key cytokines to generate langerinhigh-expressing cells but only in serum-free conditions. These cells were shown to express the LC-specific TROP-2 and Axl surface markers and contained Birbeck granules. Surprisingly, E-cadherin was not spontaneously expressed by these cells but required a direct contact with keratinocytes to be stably induced. MDLCs induced stronger allogeneic T cell proliferations but released low amounts of inflammatory cytokines upon TLR stimulation compared with donor-paired monocyte-derived dendritic cells. Immature langerinhigh MDLCs were responsive to MIP-3b/CCL20 and CTAC/CCL27 chemokine stimulations. Finally, we demonstrated that those cells behaved as bona fide LCs when inserted in a three-dimensional rebuilt epithelium by becoming activated upon TLR or UV light stimulations. Collectively, these results prompt us to propose these langerinhigh MDLCs as a relevant model to address LC biology–related questions

Generation of Rag1 and Il2rg immunodeficient rats and application to humanization studies

International audienceModeling the immune response and rational immune approaches in vivo have relied heavily on studies performed in immunodeficient mouse models. These mouse models are groundbreaking platforms to humanize different tissues and organs and to evaluate compounds to treat a variety of human diseases, from cancer and infectious diseases to allergies, inflammation and GVHD. Rats are ideally suited to perform experiments in which larger size is needed and are still a small animal model suitable for rodent facilities.We describe here the generation of Il2rg-deficient rats and their crossing with previously described Rag1-deficient rats, generating for the first time double-mutant Rat Rag1 and Il2rG KO (RRG) animals

Generation of Immunodeficient Rats With Rag1 and Il2rg Gene Deletions and Human Tissue Grafting Models

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