Project description:Background: Despite significant improvements in short-term kidney transplant survival, comparable increases in 5 and 10-year outcomes have not been achieved. Chronic allograft nephropathy (CAN) is a major cause of late graft loss. Toxic nephropathy and inadequate long-term immunosuppression are possible factors. We performed a randomized prospective trial comparing calcineurin inhibitor (CNI)-free to CNI-based immunosuppression to determine the impact on renal function, structure, and gene expression. Methods: Sixty-one kidney recipients received mycophenolate mofetil (MMF), and prednisone (P). Randomized patients received concentration-controlled sirolimus or cyclosporine. Two years post-transplant 55 patients underwent renal function studies, 48 (87%) underwent transplant biopsies; all classified by Banff scoring and 41 by DNA microarrays. Findings: Comparing sirolimus/MMF/P to cyclosporine/MMF/P at two years, there was a significantly lower serum creatinine (1.35 vs. 1.81 mg/dl; p=0.008), significantly higher Cockroft-Gault glomerular filtration rate (GFR) (80.4 vs. 63.4 cc/min; p=0.008), iothalamate GFR (60.6 vs. 49.2 cc/min; p= 0.018), and Banff 0 (normal) biopsies (66.6 vs. 20.8%; p=0.013). Regression analysis of calculated GFR’s from 1 to 36 months yielded a positive slope for sirolimus of 3.36 ml/min/year, and a negative slope for cyclosporine of –1.58 ml/min/year (p=0.008). Gene expression profiles of kidney biopsies with higher Banff CAN scores confirmed significant up regulation of genes responsible for immune/inflammation and fibrosis/tissue remodeling. Interpretation: At two years the sirolimus-treated patients have better renal transplant function, a diminished prevalence of CAN, and down regulated expression of genes responsible for the progression of CAN. All may provide for an alternative natural history with improved graft survival. Keywords = Cyclosporine Keywords = Sirolimus Keywords = Transplantation Keywords = DNA microarrays Keywords = calcineurin inhibitors Keywords: parallel sample. This dataset is part of the TransQST collection.

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 IOT samples: 13 samples from 10 Tol-DF patients, 16 samples from 11 s-LP patients, 8 samples from 8 s-nCNI patients, 40 samples from 28 s-CNI patients, 10 samples from 9 CR patients, and 8 samples from 8 HC donors were analysed on a custom Agilent 8x15K 60mer oligonucleotide microarray encomprising 5069 probes in triplicates. The microarray is dedicated to transplantation research and was designed based on current literature and published and unpublished data provided by the RISET consortium. For the probe selection procedure we specially focused on the detection of multiple transcript variants of a gene, on optimized hybridization properties of the probes, and on the avoidance of crosshybridization. The sampling dates of replicate samples from the same patient range from one day to 1.5 years. ITN samples: 31 samples from 23 Tol-DF patients, 14 samples from 11 s-LP patients, 52 samples from 34 s-CNI patients, 25 samples from 18 CR patients, and 20 samples from 20 HC donors were analysed on the same microarray platform and served as test set. The samples of the two cohorts differ in the protocol of RNA preparation.

Project description:Immune responses induced by ongoing and/or past infections prevent the establishment of transplantation tolerance in experimental animal models. How host-pathogen interactions influence allograft tolerance in humans has not been investigated before. The spontaneous development of operational tolerance in liver transplant recipients with chronic hepatitis C virus (HCV) infection constitutes a unique setting to address this question. We conducted a clinical trial of immunosuppression withdrawal in stable HCV-infected liver recipients to elucidate: i) the mechanisms through which allograft tolerance is established in the presence of an ongoing inflammatory response; and ii) how is influenced by anti-HCV heterologous immune responses. Enrolled patients gradually discontinued their immunosuppressive drugs over 6-9 months, and those who maintained normal allograft status 12 months after drug withdrawal were considered operationally tolerant. Successful drug withdrawal was associated with intra-hepatic over-expression of type I interferon and immune-regulatory genes, and correlated with an expansion of exhausted PD1/CTLA4/2B4-positive HCV-specific circulating CD8+ T cells. These findings were already present before immunosuppression was discontinued and were specific for HCV infection. In contrast, the magnitude of HCV-induced inflammatory gene expression and the scope of anti-HCV effector T cell responses did not influence drug withdrawal outcome. Our data indicate that in humans persistent viral infections do not necessarily preclude the development of transplantation tolerance. At least in HCV-infected liver allografts, mechanisms associated with the capacity of the virus to evade adaptive immunity could contribute to the restraining of alloimmune responses and the establishment of transplantation tolerance. Transcriptomic study from the following liver tissue samples: 12 tolerant before immunosuppression (IS), 13 non-tolerant before IS, 4 from non-tolerant at the time of rejection, 13 from tolerant patients 12 months after IS discontinuation. Additionally, 8 liver tissue samples obtained from healthy living liver donors undergoing partial hepatectomy were included as non-transplanted controls.

Project description:Background: Despite significant improvements in short-term kidney transplant survival, comparable increases in 5 and 10-year outcomes have not been achieved. Chronic allograft nephropathy (CAN) is a major cause of late graft loss. Toxic nephropathy and inadequate long-term immunosuppression are possible factors. We performed a randomized prospective trial comparing calcineurin inhibitor (CNI)-free to CNI-based immunosuppression to determine the impact on renal function, structure, and gene expression. Methods: Sixty-one kidney recipients received mycophenolate mofetil (MMF), and prednisone (P). Randomized patients received concentration-controlled sirolimus or cyclosporine. Two years post-transplant 55 patients underwent renal function studies, 48 (87%) underwent transplant biopsies; all classified by Banff scoring and 41 by DNA microarrays. Findings: Comparing sirolimus/MMF/P to cyclosporine/MMF/P at two years, there was a significantly lower serum creatinine (1.35 vs. 1.81 mg/dl; p=0.008), significantly higher Cockroft-Gault glomerular filtration rate (GFR) (80.4 vs. 63.4 cc/min; p=0.008), iothalamate GFR (60.6 vs. 49.2 cc/min; p= 0.018), and Banff 0 (normal) biopsies (66.6 vs. 20.8%; p=0.013). Regression analysis of calculated GFR’s from 1 to 36 months yielded a positive slope for sirolimus of 3.36 ml/min/year, and a negative slope for cyclosporine of –1.58 ml/min/year (p=0.008). Gene expression profiles of kidney biopsies with higher Banff CAN scores confirmed significant up regulation of genes responsible for immune/inflammation and fibrosis/tissue remodeling. Interpretation: At two years the sirolimus-treated patients have better renal transplant function, a diminished prevalence of CAN, and down regulated expression of genes responsible for the progression of CAN. All may provide for an alternative natural history with improved graft survival. Keywords = Cyclosporine Keywords = Sirolimus Keywords = Transplantation Keywords = DNA microarrays Keywords = calcineurin inhibitors Keywords: parallel sample

Project description:Survival of solid organ grafts depends on life-long immunosuppression, which results in increased rates of infection and malignancy. Induction of tolerance to allografts would represent the optimal solution for controlling both chronic rejection (CR) and side effects of immunosuppression. Although spontaneous ‘‘operational tolerance’’ can occur in human kidney transplantation, the lack of noninvasive peripheral blood biological markers of this rare phenomenon precludes the identification of potentially tolerant patients in whom immunosuppression could be tapered as well as the development of new tolerance inducing strategies. Here, the potential of high throughput microarray technology to decipher complex pathologies allowed us to study the peripheral blood specific gene expression profile and corresponding EASE molecular pathways associated to operational tolerance in a cohort of human kidney graft recipients. In comparison with patients with CR, tolerant patients displayed a set of 343 differentially expressed genes, mainly immune and defense genes, in their peripheral blood mononuclear cells (PBMC), of which 223 were also different from healthy volunteers. Using the expression pattern of these 343 genes, we were able to classify correctly >80% of the patients in a cross-validation experiment and classified correctly all of the samples over time. Collectively, this study identifies a unique PBMC gene signature associated with human operational tolerance in kidney transplantation. 250 samples were analyzed, replicates included: some patients from the TOL and CR groups were sampled twice with an interval between the two different time points of at least 16 months (mean 25.8 months, range 16–31 months). All the samples were analyzed in duplicate or quadruplicate. 1. TOL (n = 21). patients with stable graft function (blood creatinemia<150 mmol/L, proteinuria<1 g/24 h) for at least 1 year (mean 6.4 years,range 1.6–17.2 years) after complete interruption of immunosuppressive therapy. 2. STA (n = 190). Patients with stable kidney graft function under immunosuppressive therapy. 3. CR (n = 31). Patients having a progressive degradation of their renal function (blood creatinemia ≥150 mmol/L, proteinuria ≥1 g/24 h). CR was diagnosed on a graft biopsy according to the updated Banff criteria. CR was defined by histological signs of chronic allograft arteriopathy (arterial intimal fibrosis with mononuclear cell infiltration) and/or transplant glomerulopathy with glomerular double contours. 4. HV (n = 8). Subjects having normal blood formulae and no infectious or other concomitant pathology for at least 6 months before the study.

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GENOMICS TO IDENTIFY HLA IDENTICAL RENAL TRANSPLANT TOLERANCE SIGNATURES

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