Project description:The achievement of a drug-free operational tolerance for renal transplanted patients is a major goal in organ transplantation. Previous gene expression profiling in peripheral blood mononuclear cells (PBMC) identified genes associated with operational tolerance. The identification of a common pattern of B cell-related genes associated with tolerance encourage us to analyze gene expression in purified B cell from operationally tolerant patients (TOL=10) compared to renal transplanted patients with stable graft function (STA=12) under immunosuppression and also compared to healthy volunteers (HV=10) who have no immunosuppressive treatment and no graft. Microarray analyses exhibited an absence of gene signature associated with tolerance in purified B cell compared to STA or HV. These results suggest that the B cell signatures observed in PBMC may be due to an increase number of total B cells rather than specific B cell characteristics in operationally tolerant patients. This dataset represents gene expression profiling of purified B cells from 10 renal transplanted patients with operational tolerance (TOL), 12 renal transplanted patients with stable graft function under immunosuppression (STA) and 10 healthy volunteers (HV).
Project description:The role of B cells after transplant regarding allograft rejection or tolerance has become a topic of major interest. Recently, in renal transplant recipients, a B cell signature characterized by the overexpression of CD19+CD38hiCD24hi transitional B cells has been observed in operationally tolerant patients and in Belatacept treated patients with significant lower incidence of donor specific antibodies. The phenotypic and functional characterization of these transitional B cells is far to be exhaustive. We present the first transcriptomic and phenotypic analysis associated with this phenotype. Three populations were studied and compared: (i) transitional CD24hiCD38hi (ii) CD24+CD38- and (iii) CD24intCD38int populations.
Project description:The achievement of a drug-free operational tolerance for renal transplanted patients is a major goal in organ transplantation. Previous gene expression profiling in peripheral blood mononuclear cells (PBMC) identified genes associated with operational tolerance. The identification of a common pattern of B cell-related genes associated with tolerance encourage us to analyze gene expression in purified B cell from operationally tolerant patients (TOL=10) compared to renal transplanted patients with stable graft function (STA=12) under immunosuppression and also compared to healthy volunteers (HV=10) who have no immunosuppressive treatment and no graft. Microarray analyses exhibited an absence of gene signature associated with tolerance in purified B cell compared to STA or HV. These results suggest that the B cell signatures observed in PBMC may be due to an increase number of total B cells rather than specific B cell characteristics in operationally tolerant patients.
Project description:The role of B cells after transplant regarding allograft rejection or tolerance has become a topic of major interest. Recently, in renal transplant recipients, a B cell signature characterized by the overexpression of CD19+CD38hiCD24hi transitional B cells has been observed in operationally tolerant patients and in Belatacept treated patients with significant lower incidence of donor specific antibodies. The phenotypic and functional characterization of these transitional B cells is far to be exhaustive. We present the first transcriptomic and phenotypic analysis associated with this phenotype. Three populations were studied and compared: (i) transitional CD24hiCD38hi (ii) CD24+CD38- and (iii) CD24intCD38int populations. Peripheral blood mononuclear cells were isolated from 5 healthy donors and CD20+ B cells were isolated by magnetic beads. Three B cells populations were then sorted by flow cytometry: CD19+CD24hiCD38hi (test), CD19+CD24+CD38- (control 1) and CD19+CD24intCD38int (control 2)
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:The development of reliable biomarkers of transplant tolerance would enhance the safety and feasibility of clinical trials and potentially also facilitate management of patients on standard immunosuppressive therapies. To this end, we examined peripheral blood samples of spontaneously tolerant renal transplant recipients, as well as patients enrolled in two interventional tolerance trials, using multiparameter flow cytometry and gene expression analysis. Repeat analysis of samples from a previously reported tolerant cohort, as well as newly identified tolerant patients, confirmed that tolerance was associated with increased expression of B cell-associated genes relative to immunosuppressed patients with stable renal function. This was not accounted for merely by an increase in total B cell numbers, but appeared to be the result of increased frequencies of transitional and naïve B cells. Moreover, serial measurements demonstrated that this pattern persisted over several years. Importantly, patients rendered tolerant via induction of transient mixed chimerism, and those weaned to low levels of immunosuppression, showed similar increases in the expression of selected B cell genes as did spontaneously tolerant individuals. Collectively, these findings support the notion that alterations in B cells may be a common theme for tolerant kidney transplant recipients, and a useful immune monitoring tool in prospective trials. The MassARRAY QGE (Sequenom) multiplexed primer and competitive template designs and analysis were reported previously.
Project description:Genomic Analysis of more than 400 patients from multi-center transplant programs and clinical trials provides a non-invasive QPCR based gene expression test for operational renal allograft tolerance 3 group comparison of blood from TOL, CAN and Non-transplant healthy controls (HD) allografts. Biological replicates: 16 TOL, 10 CAN and 5 HC
Project description:Genomic Analysis of more than 400 patients from multi-center transplant programs and clinical trials provides a non-invasive QPCR based gene expression test for operational renal allograft tolerance