Project description:Experiments in preclinical transplant models have indicated that preoperative administration of donor-derived M regs to transplant recipients may promote beneficial regulatory responses to a subsequent allograft. This contention is supported by results from the TAIC-I and –II clinical studies, which demonstrated that infusion of a crude cell preparation containing regulatory macrophages was both safe and could promote a state of donor-specific hyporesponsiveness. In an extension of this work, two patients were treated with donor-derived M regs prior to receiving a living-donor kidney transplant. Keywords: Classification of clinical samples
Project description:Human regulatory macrophages (Mreg) have shown early clinical promise as a cell-based, adjunct immunosuppressive therapy in solid organ transplantation. It is hypothesised that recipient CD4+ T cell responses are actively regulated through direct allorecognition of donor-derived Mregs. Here we show that human Mregs convert allogeneic CD4+ T cells to IL-10-producing, TIGIT+ FoxP3+ induced regulatory T cells that non-specifically suppress bystander T cells and inhibit dendritic cell maturation. Differentiation of Mreg-induced Tregs (miTregs) relies on multiple, non-redundant mechanisms that are not exclusive to interaction of Mregs and T cells, including signals mediated by indoleamine 2,3-dioxygenase, TGF-β, retinoic acid, Notch and progestagen-associated endometrial protein. Preoperative administration of donor-derived Mregs to living-donor kidney transplant recipients results in an acute increase in circulating TIGIT+ Tregs. These results suggest a feed-forward mechanism by which Mreg treatment promotes allograft acceptance through rapid induction of direct pathway Tregs.
Project description:A preoperative short-term diet combining calorie and protein restriction diet given during five days before kidney donation and transplantation improves kidney outcome in live kidney donors and kidney transplant recipients, which shows that the benefits of dietary restriction on stress resistance can be induced rapidly in humans, and may be used for clinically relevant endpoints.
Project description:We characterized the transcriptome and methylome of renal progenitor cells in the urine of a cohort of stable kidney transplant recipients to elucidate whether the origin of the donor (living or deceased donor) was associated with a specific molecular reprogramming.
Project description:Donor organ shortage, growing waiting lists and organ discard rates are key problems in kidney transplantation. Donor organ quality is a critical factor determining post-transplant graft outcomes. However, organ quality is difficult to predict. Balancing the use of marginal donors without affecting outcomes is a main issue in the transplant field. The decision of acceptance of a kidney organ for transplantation is mainly based on donor organ biopsy findings, even though there are recognized limitations. The lack of better measures of organ quality at the time of transplantation as a predictor of performance graft outcome is a serious clinical challenge. Herein, we propose the use of a limited set of genes that captures intrinsic biology of kidney donor organs to improve available scoring systems. We studied gene expression in 192 deceased donor kidney biopsies and evaluated short-term outcomes which included delayed graft function and eGFR (high versus low) at 24 months for 168 kidney transplant recipients.
Project description:Donor-specific antibody (DSA) responses against human leukocyte antigen (HLA) proteins mismatched between kidney transplant donors and recipients cause allograft loss. Using single cell, molecular, structural, and proteomic techniques, we profiled the HLA-specific (alloreactive) B cell response in kidney and blood of a transplant recipient with antibody-mediated rejection (AMR). We identified 14 distinct alloreactive B cell lineages, which spanned the rejected organ and blood and expressed high-affinity anti-donor HLA-specific B cell receptors – many of which were clonally linked to circulating DSA. The alloreactive B cell response was focused on exposed, solvent-accessible mismatched HLA residues, while also demonstrating extensive contacts with self-HLA residues. Consistent with structural evidence of self-recognition, measurable autoreactivity by donor-specific B cells was common and positively correlated with anti-donor affinity maturation. Thus, allo- and self-reactive signatures appeared to converge, suggesting that during AMR, the recognition of non-self and breaches of tolerance conspire to produce a pathogenic donor-specific adaptive response.
Project description:Antibody-mediated rejection, caused by antibodies against the donor human leukocyte antigen (HLA) molecules plays a fundamental role in graft rejection in transplantation. Most significant is transplant patients who generate antibodies against the donor HLA-DQ have the highest risk of rejection. In this study, we investigated the role of indirect CD4 T cell epitopes in the formation of donor-specific antibodies (DSA). Using antigen mapping techniques in kidney and heart transplant recipients with HLA-DQ DSA, we identified two polymorphic hotspots in the HLA-DQ gene that generated alloreactive CD4 T cell responses. To study the functional significance of indirect CD4 T cells, we first mapped epitopes recognised by H2-Kb C57Bl6 mice against a skin graft from H2-Kd Balb/c mice. We identified a CD4 T cell epitope, specific for amino acids 287-301 derived from the H2-Kd protein, that generated tetramer-binding Kd287+ CD4 T cells during rejection. Importantly, the transfer of Kd287+ CD4 T cells into T cell-deficient mice was sufficient to drive an antibody response against the donor H2-Kd molecule. Lastly, we found that administration of systemic high-dose donor H2-Kd peptides combined with CTLA4-Ig reduced the formation of Kd287+ CD4 T cells and diminished DSA formation. Together, these findings demonstrate that the identification of donor antigens indicates the potential for inducing donor-specific immune tolerance in transplantation.
Project description:Being able to identify patients in whom immunological tolerance has been established or is developing would allow an individually tailored approach to post-transplant management of kidney allograft recipients. Ex vivo immunological monitoring was performed on samples from five groups of European renal transplant recipients (“IOT samples”): ten drug-free tolerant recipients who were functionally stable despite remaining immunosuppression-free for more than one year (Tol-DF); also functionally stable patients on minimal immunosuppression (<10 mg/day prednisone, s-LP); stable patients maintained with calcineurin inhibitors (s-CNI); stable patients maintained on CNI-free immunosuppression regimen (s-nCNI); patients showing signs of chronic rejection (CR) and healthy controls (HC). Among the investigation of other biomarkers and bioassays, gene expression profiles were generated on custom Agilent 8x15K 60mer oligonucleotide microarrays (“RISET 2.0”) on the IOT cohort (training set) and on an independent cohort of patients from the ITN (USA) that contained similar groups of patients and included 23 tolerant recipients (“ITN samples”, test set). Set of genes were identified, whose expression on whole blood allowed the identification of 100% of the tolerant recipients in the training set and 84% in the test set. Keywords: classification of clinical samples, tolerance prediction
Project description:Donor-specific antibody (DSA) responses against human leukocyte antigen (HLA) proteins mismatched between kidney transplant donors and recipients cause allograft loss. Using single cell, molecular, structural, and proteomic techniques, we profiled the HLA-specific (alloreactive) B cell response in kidney and blood of a transplant recipient with antibody-mediated rejection (AMR). We identified 14 distinct alloreactive B cell lineages, which spanned the rejected organ and blood and expressed high-affinity anti-donor HLA-specific B cell receptors – many of which were clonally linked to circulating DSA. The alloreactive B cell response was focused on exposed, solvent-accessible mismatched HLA residues, while also demonstrating extensive contacts with self-HLA residues. Consistent with structural evidence of self-recognition, measurable autoreactivity by donor-specific B cells was common and positively correlated with anti-donor affinity maturation. Thus, allo- and self-reactive signatures appeared to converge, suggesting that during AMR, the recognition of non-self and breaches of tolerance conspire to produce a pathogenic donor-specific adaptive response.