Intragraft molecular pathways associated with tolerance induction in renal transplantation
ABSTRACT: Complications associated with immunosuppression, specifically nephrotoxicity and infection risk, significantly affect graft and patient survival after kidney transplantation. We previously showed that tolerance could be induced and full donor chimerism, as well as immunosuppression withdrawal, was obtained in highly mismatched allograft recipients using a bioengineered stem cell product (FCRx). Overall design: Gene expression profiles in renal biopsy samples from tolerance-induced FCRx recipients, paired donor organs before implant, and subjects under standard immunosuppression (SIS) without rejection and with acute rejection were compared.
INSTRUMENT(S): [HG-U133A_2] Affymetrix Human Genome U133A 2.0 Array
Project description:Immunosuppression is needed in HLA identical sibling renal transplantation. We conducted a tolerance trial in this patient cohort using Alemtuzumab induction, donor hematopoietic stem cells, tacrolimus/mycophenolate immunosuppression converted to sirolimus, planning complete drug withdrawal by 24 months post-transplantation. After an additional 12 months with no immunosuppression, normal biopsies and renal function, recipients were considered tolerant. Twenty recipients were enrolled. Of the first 10 (>36 months post-transplantation), 5 had immunosuppression successfully withdrawn for 16-36 months (tolerant), 2 had disease recurrence and 3 had subclinical rejection in protocol biopsies (non-tolerant). Microchimerism disappeared after 1 year, and CD4+CD25highCD127-FOXP3+ T cells and CD19+IgD/M+CD27- B cells increased to 5 years post-transplantation in both groups, whereas immune/inflammatory gene expression pathways in the peripheral blood and urine were differentially downregulated in tolerant compared to non-tolerant recipients. Therefore, in this HLA identical renal transplant tolerance trial, absent chimerism, Treg and Breg immunophenotypes were indistinguishable between tolerant and non-tolerant recipients, but global genomic changes indicating immunomodulation were observed only in tolerant recipients. A total of 46 PBMC samples representing blood draws from four time points in the first 9 recipients were processed for microarray analysis (The Scripps Research Institute, La Jolla, CA). The analyzed time points were: immediately pre-operatively in the absence of immunosuppression (n=9); post-operatively at 1 year (n=8, range 11-13 months); at 2 years (n=12, range 18-25 months); >3 years (n=17, range 32-48 months). (At year 2 and at > 3 years, repeated samples were obtained from individual subjects, and at one year, one subject had a technically unsatisfactory sample.) To discount the effects of immunosuppression on gene expression, microarray data were included on whole blood from 18 healthy human subjects (controls: GSE40586; NCBI Gene Expression Omnibus [GEO] repository).
Project description:Background Immune tolerance and persistent mixed chimerism can be achieved reproducibly after combined organ and hematopoietic cell transplantation in mice conditioned with total lymphoid irradiation plus anti-thymocyte globulin. We studied the safety and reproducibility of this approach in a cohort of kidney transplant patients, and tried to identify immune monitoring procedures that can predict tolerance and guide complete immunosuppressive drug withdrawal. Methods Ten patients conditioned with 10 doses of total lymphoid irradiation and 5 doses of anti-thymocyte globulin were given kidney transplants and an injection of CD34+ hematopoietic progenitor cells and T cells from HLA matched donors. Blood cell monitoring included changes in chimerism, balance of T cell subsets, gene expression, and responses to donor alloantigens. Results Nine of 10 patients developed multi-lineage chimerism without graft versus host disease (GVHD), and all had excellent graft function at the last observation point. Five of these with chimerism persisting for at least 12 months were completely withdrawn from immunosuppressive drugs for 6 to 35 months. Blood cells from patients off drugs showed development of specific unresponsiveness to donor alloantigens, “tolerance” profiles on gene microarrays, early high ratios of regulatory versus conventional naïve T cells, and early high levels of chimerism among NK cells. Conclusions Total lymphoid irradiation, and anti-thymocyte globulin promoted the development of persistent chimerism and tolerance in a cohort of patients given kidney transplants and donor cell injections. Assays were identified that can assist in the safe withdrawal of immunosuppressive drugs. Overall design: 45 Agilent Microarray samples were conducted, including 16 tolerance patients, 10 chronic rejection patients, 5 healthy normal controls, and 7 paired pre and post-transplant induced tolerance patients. The aim is to see whether induced tolerance patients show operational tolerance gene expression signature and can withdraw or minimize the immunosuppression regimens.
Project description:Background Immune tolerance and persistent mixed chimerism can be achieved reproducibly after combined organ and hematopoietic cell transplantation in mice conditioned with total lymphoid irradiation plus anti-thymocyte globulin. We studied the safety and reproducibility of this approach in a cohort of kidney transplant patients, and tried to identify immune monitoring procedures that can predict tolerance and guide complete immunosuppressive drug withdrawal. Methods Ten patients conditioned with 10 doses of total lymphoid irradiation and 5 doses of anti-thymocyte globulin were given kidney transplants and an injection of CD34+ hematopoietic progenitor cells and T cells from HLA matched donors. Blood cell monitoring included changes in chimerism, balance of T cell subsets, gene expression, and responses to donor alloantigens. Results Nine of 10 patients developed multi-lineage chimerism without graft versus host disease (GVHD), and all had excellent graft function at the last observation point. Five of these with chimerism persisting for at least 12 months were completely withdrawn from immunosuppressive drugs for 6 to 35 months. Blood cells from patients off drugs showed development of specific unresponsiveness to donor alloantigens, “tolerance” profiles on gene microarrays, early high ratios of regulatory versus conventional naïve T cells, and early high levels of chimerism among NK cells. Conclusions Total lymphoid irradiation, and anti-thymocyte globulin promoted the development of persistent chimerism and tolerance in a cohort of patients given kidney transplants and donor cell injections. Assays were identified that can assist in the safe withdrawal of immunosuppressive drugs. 45 Agilent Microarray samples were conducted, including 16 tolerance patients, 10 chronic rejection patients, 5 healthy normal controls, and 7 paired pre and post-transplant induced tolerance patients. The aim is to see whether induced tolerance patients show operational tolerance gene expression signature and can withdraw or minimize the immunosuppression regimens.
Project description:Complications due to long-term administration of immunosuppressive therapy increase the morbidity and mortality of liver transplant recipients. Discontinuation of immunosuppressive drugs in recipients spontaneously developing operational tolerance could substantially lessen this burden. However, this strategy results in the development of rejection in a high proportion of recipients who require lifelong immunosuppression. Thus, there is a need to identify predictive factors of successful drug withdrawal and to define the clinical and histological outcomes of operationally tolerant liver recipients. Methods. We enrolled 102 stable liver transplant recipients in an immunosuppression withdrawal trial in which drugs were gradually discontinued over a 6-9 month period. Patients with stable graft function and no signs of rejection in a liver biopsy conducted 12 months after cessation of immunosuppressive therapy were considered operationally tolerant. Results. Out of the 98 recipients who completed the study, immunosuppression discontinuation was successful in 41 recipients and rejection occurred in 57. Rejection episodes were mild and were resolved in all cases. Development of tolerance was independently associated with time elapsed since transplantation, recipient age, and male gender. No histological damage was apparent in protocol biopsies performed after successful drug withdrawal. Overall design: PBMC gene expression profiling was assessed by DNA microarray in liver trasplanted patients groups: A group of inmunetolerant patients (TOL ;n=20), a group of non inmunotolerant (NonTOL; n=25). Finally from these two groups (Tolerant pTOL=12 and Non Tolerant pNonTOL=14 ) a sample is obtained a year after weaning.
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. Overall design: 67 PBL (Peripheral Blood Leukocytes) samples from 6 groups (TOL, MIS, STA, AR, CR, N) were analyzed by microarray.
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. Overall design: Total of 25 TOL (Tolerant), 7 New TOL (New Tolerant), 34 SI (Standard Immunosuppression) in cohort ITN507; 7 Sirolimus Monotherapy, 2 SI Multiagent in cohort ITN013; and 7 TOL and 1 Return to SI in cohorts ITN010 and ITN036.
Project description:Inducing graft acceptance without chronic immunosuppression remains an elusive goal in organ transplantation. Recent data demonstrate that non-self recognition by graft infiltrating macrophages initiates transplant rejection. Using an experimental transplantation mouse model, we isolated graft-infiltrating macrophages from two transplantation settings: untreated rejecting mice and treated with mTORi-HDL nanobiologics. We used microarrays to detail the global programme of gene expression underlying macrophage dependent organ transplant rejection and identified distinct classes of up-regulated genes during this process, which are down-regulated following tolerogenic treatment with mTORi-HDL nanobiologics. Overall design: BALB/c donor hearts were transplanted into fully allogeneic C57BL/6 mice. Transplant recipients were either left untreated (Control) and rejected their allografts or were treated with mTORi-HDL nanobiologics (Sample) on days 0, 2, and 5 post-transplantation. Donor heart allografts were isolated on day 6 post-transplantation and graft-infiltrating macrophages were isolated by fluorescence-activated cell sorting (FACS) for microarray analysis.
Project description:In clinical organ transplantation complete cessation of immunosuppressive therapy can be successfully accomplished in selected recipients providing a proof-of-principle that allograft tolerance is attainable in humans. The intra-graft molecular pathways associated with human allograft tolerance, however, have not been comprehensively studied before. In this study we analyzed sequential liver tissue samples collected from liver recipients enrolled in a prospective multicenter immunosuppressive withdrawal clinical trial. Tolerant and non-tolerant recipients differed in the intra-graft expression of genes involved in the regulation of iron homeostasis.These results point to a critical role of iron homeostasis in the regulation of intra-graft alloimmune responses in humans and provide a set of novel biomarkers to conduct drug-weaning trials in liver transplantation. The complete database comprised the expression measurements of 48766 probes in liver biopsies. The liver biopsy specimens available for the study were obtained: a) before immunosuppressive drugs were discontinued from tolerant (TOL, n=24) and non-tolerant (Non-TOL, n=29) recipients; b) at the time of rejection from non-tolerant recipients (Non TOL REJ, n=18); In addition, liver tissue samples were also collected from the following control patient groups: a) liver transplant recipients with chronic hepatitis due to recurrent hepatitis C virus infection (HEPC, n=12); b) liver transplant recipients with typical acute cellular rejection taking place during the immediate post-transplant period (REJ, n=9); c) liver transplant recipients under maintenance immunosuppression with normal liver function and normal liver histology 1 year after transplantation (CONT-Tx, n=8); and d) non-transplanted patients undergoing surgery for colorectal liver metastases (CONT, n=10).
Project description:Xenotransplantation holds the promise of providing an unlimited supply of donor organs for terminal patients with organ failure. The gal carbohydrate results in rejection of wild type pig grafts, however, chimerism established by expression of the GalT gene prior to transplantation in GalT knockout mice results in tolerance to Gal+ heart grafts. We used microarrays in order to further understand the early events that occur within grafts that demonstrate tolerance. Experiment Overall Design: The GalT BMT recipient is a GalT knockout mouse which recieved GalT gene transduced allo-bone marrow cells transplantation after sublethal irradiation. A heart of wild type C57BL/6 was heterotopically transplanted into the recipient after GalT BMT. Syngeneic Control recipient is a wild type C57BL/6 transplanted a heart of wild C57BL/6.
Project description:Measurement of specific gene expression in clinical samples is a promising approach for monitoring the recipient immune status to the graft in organ transplantation. Identification of biomarker genes closely associated with tolerance or rejection is critical for this monitoring protocol. Unlike previous studies, our microarray analysis focused on donor antigen-reactive T cells, which were prepared by collecting CD69+ T cells from cocultures of recipient peripheral T cells and donor antigen-presenting cells. A comparison of different recipient groups enabled us to identify several tolerance- and rejection-correlated biomarker genes, including previously unknown genes. By measuring biomarker gene expression in the CD69+ T cell fraction using quantitative reverse-transcription polymerase chain reaction, we were able to precisely detect the immune status of recipients relative to their graft. Full-thickness donor (BDF1; C57BL/6 x DBA/2) tail skin was grafted onto recipient (C57BL/6) mice. Tolerance to the graft was induced by donor specific transfusion combined with administration of anti-CD40L Ab (MR-1). Total T lymphocytes were prepared from spleen and lymph nodes of tolerant recipient mice on day 100 after skin transplantation, untreated recipient mice on day 7, and ungrafted, healthy C57BL/6 mice and used as tolerant, rejecting and naïve T lymphocyte samples, respectively. In order to isolate alloantigen-reactive cells, T lymphocytes were cocultured with donor T cell-depleted splenocytes for 20-21 hours and then separated into two subpopulations based on CD69 expression using fluorescence cell sorter. Total RNA was extracted from these CD69+ and CD69- T cells and subjected to microarray using Illunima MouseWG-6 Expression BeadChip. All data analysis and visualization of differentially expressed genes was conducted using Illumina GenomeStudio v2009.2 (Gene Expression Module v1.5.4) and R statistical language v2.6.1. Candidate tolerance genes were defined as the common genes satisfying the following criteria; 1) 1.5 fold or higher expression in CD69+ T cells isolated from tolerant recipients than those from naïve mice, 2) 1.5 fold or higher expression in CD69+ T cells than CD69- T cells from tolerant mice, 3) 500 or higher average signal measured in CD69+ T cells from tolerant mice. The criteria for candidate rejection genes were 1) 1.5 fold or higher expression in CD69+ T cells isolated from rejecting recipients than those from tolerant mice, 2) 1.5 fold or higher expression in CD69+ T cells than CD69- T cells from rejecting mice, 3) 500 or higher average signal measured in CD69+ T cells from rejecting mice.