Unknown,Transcriptomics,Genomics,Proteomics

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A Common Peripheral Blood Gene-Set for Diagnosis and Prediction of Operational Tolerance in Pediatric and Adult Liver Transplantation

ABSTRACT: The ability to identify a robust means for both pediatric and adult liver transplant recipients for minimization and weaning of immunosuppression is greatly needed. We analyzed 298 samples from pediatric (n=83) and published adult (n=57) liver transplant recipients, and the public available cell or tissue specific samples (n=158). Biomarkers were first identified from the integration of the cross-platform analysis of Stanford pediatric and adult studies and validated in independent samples from UCLA on microarray. Furthermore, Q-PCR was performed for targets validation and delivers a robust diagnostic assay of predicting potential liver tolerance after liver transplantation. Thirteen unique genes were identified (FDR<5%) using nearest shrunken centroid classification methods as a minimum gene set to cross-validate and predict Stanford pediatric tolerance samples with 1misclassification, 5 misclassification for adult samples, and 100% sensitivity and 83% specificity for an independent UCLA pediatric samples in microarray platform. These subset of tolerant specific genes are highly expressed CD56+ natural killer cells (p=0.03). Furthermore, the subset can be narrowed down to 3 key genes with combined ROC=0.988 for the liver tolerance prediction from Q-PCR verification and 64% MIS and STA were predicted as tolerance with the >90% prediction probability. Specific peripheral transcriptional programs can be identified in operational tolerance in pediatric recipients of liver allografts, distinct from those previously identified in adult operationally tolerant liver recipients, and may provide a means to non-invasively monitor patients in a serial manner for immunosuppression minimization. These genes are highly expressed in specific peripheral blood lymphocyte subsets, and their coordinated may support the maintenance of operational tolerance in children, following liver transplantation. Two centers data was included, which are 41 samples from Stanford as the training set and 44 samples from UCLA as the test set. 26 samples from Stanford and 15 samples from UCLA were used in microarray Agilent whole human genome microarray

ORGANISM(S): Homo sapiens

SUBMITTER: Li Li

PROVIDER: E-GEOD-30886 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Operational tolerance after solid organ transplantation is defined as stable graft acceptance without immunosuppression while maintaining normal immunocompetence against immunological insults. However, it is not clear yet which cellular and molecular pathways are driving tolerance in these patients and how this state can be induced in order to improve graft survival. Several transcriptomic analysis have shown that transcription signatures in blood can reflect the immunological state associated with operational tolerance in kidney transplant. Nonetheless, epigenetic dynamics orchestrating these transcription signatures have not yet been studied. Here, we performed genome-wide analysis of DNA methylation of kidney transplant recipients with chronic rejection and operational tolerance. Our data showed that chronic rejection and operational tolerance recipients have differential DNA methylation in 2737 genes, indicating that each patient group has a specific epigenetic signature associated with transplant outcome. In addition, we observed that operational tolerance is associated with DNA demethylation in genes involved in immune function, including B cell activation (e.g. ST6GAL1, MS4A1 and MEF2C) and the Th17 differentiation program (e.g. LY9 and BATF), while in CR patients is mostly associated intracellular signaling and ubiquitination pathways. Finally, we used weighted gene co-expression network analysis (WGCNA) to select the more defining epigenetic changes associated with operational tolerance. By this method, we select 12 genomic regions specifically hypomethylated (HIVEP2, HOMER1, UTRN, PTPRO, SP100 and JAZF1) or hypermethylated (EMZ8, EZR-AS, WDR20, NADSYN1, TBCD and MED17) in tolerant patients. Analysis of these genes in stable transplant recipients with immunosuppression showed that these patients have a similar methylation signature to operational tolerance recipients. Overall, these results demonstrate that DNA methylation in blood can mirror the immune status associated with kidney transplant outcome and provides a starting point for understanding the epigenetic mechanisms associated with operational tolerance.

Project description:Long-term allograft survival generally requires lifelong immunosuppression. Rarely, recipients display spontaneous operational tolerance with stable graft function in the absence of immunosuppression. The lack of biological markers of this phenomenon precludes identification of potentially tolerant patients in which immunosuppression could be tapered and hinders the development of new tolerance inducing strategies. The objective of this study was to identify minimally invasive blood biomarkers for operational tolerance and utilize these biomarkers to determine the frequency of this state in immunosupressed patients with stable graft function. Blood gene expression profiles from 75 renal transplant patient cohorts (operational tolerance/acute and chronic rejection/stable graft function on immunosuppression) and 16 healthy individuals were analyzed. A subset of samples was used for microarray analysis where three-class comparison of the different groups of patients identified a tolerant footprint of 49 genes. These biomarkers were applied for prediction of operational tolerance by microarray and real-time PCR in independent test-groups. 33/49 genes correctly segregated tolerance and chronic rejection phenotypes with 99% and 86% specificity. The signature is shared with 1/12 and 5/10 stable patients on triple immunosuppression and low dose steroid monotherapy respectively. The gene signature suggests a pattern of reduced co-stimulatory signaling, immune quiescence, apoptosis and memory T cell responses. This study identifies in the blood of kidney recipients a set of genes associated with operational tolerance that may have utility as a minimally-invasive monitoring tool for guiding immunosuppression titration. Further validation of this tool for safe immunosuppression minimization in prospective clinical trials is warranted. 67 samples were analyzed, no replicates included: 1. TOL (n = 12). patients with long-term stable graft function, without immunosuppression for at least 2 years 2. MIS (n = 10). Patients with stable graft function on steroid monotherapy (<10 mg/day) for 4.6. Calcineurin inhibitors and CellCept were removed in these patients because of previous posttransplant lymphoproliferative disease (n = 6), cancer (n = 2), or uncontrolled infectious disease (n = 2). 3. STA (n = 12). Patients with stable kidney graft function at >5 years posttransplantation while under mycophenolate mofetil or azathioprine and maintenance steroids with (n = 5) or without (n = 7) an associated calcineurin inhibitor. 4. AR (n = 14). Patients experiencing rapid decline (>20% from baseline) in graft function and biopsy-proven AR. 5. CR (n = 11). Patients having a progressive degradation of their renal function (creatinine clearance of <60 ml per min per 1.73 m2 and/or proteinuria of >1.5 g/day) and histological signs CR. 6. N (n = 8). These subjects all had normal blood formulae and no infectious or other concomitant pathology for at least 6 months before the study.

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.

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A Common Peripheral Blood Gene-Set for Diagnosis and Prediction of Operational Tolerance in Pediatric and Adult Liver Transplantation

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