ABSTRACT: We studied intragraft gene expression profiles of positive crossmatch (+XM) kidney transplant recipients who develop transplant glomerulopathy (TG) and those who do not. Whole genome microarray analysis and quantitative rt-PCR for 30 transcripts were performed on RNA from protocol renal allograft biopsies in 3 groups: 1) +XM/TG+ biopsies before and after TG; 2) +XM/NoTG; and 3) negative crossmatch kidney transplants (control). Microarray comparisons showed few differentially expressed genes between paired biopsies from +XM/TG+ recipients before and after the diagnosis of TG. Comparing +XM/TG+ and control groups, significantly altered expression was seen for 2,447 genes (18%) and 3,200 genes (24%) at early and late time points, respectively. Canonical pathway analyses of differentially expressed genes showed inflammatory genes associated with innate and adaptive immune responses. Comparing +XM/TG+ and +XM/NoTG groups, 3,718 probe sets were differentially expressed but these were over-represented in only 4 pathways. A classic accommodation phenotype was not identified. Using rt-PCR, the expression of inflammatory genes was significantly increased in +XM/TG+ recipients compared to control biopsies and to +XM/NoTG biopsies. In conclusion, pre-transplant DSA results in a gene expression profile characterized by inflammation and cellular infiltration and the majority of XM+ grafts are exposed to chronic injury.
Project description:We studied intragraft gene expression profiles of positive crossmatch (+XM) kidney transplant recipients who develop transplant glomerulopathy (TG) and those who do not. Whole genome microarray analysis and quantitative rt-PCR for 30 transcripts were performed on RNA from protocol renal allograft biopsies in 3 groups: 1) +XM/TG+ biopsies before and after TG; 2) +XM/NoTG; and 3) negative crossmatch kidney transplants (control). Microarray comparisons showed few differentially expressed genes between paired biopsies from +XM/TG+ recipients before and after the diagnosis of TG. Comparing +XM/TG+ and control groups, significantly altered expression was seen for 2,447 genes (18%) and 3,200 genes (24%) at early and late time points, respectively. Canonical pathway analyses of differentially expressed genes showed inflammatory genes associated with innate and adaptive immune responses. Comparing +XM/TG+ and +XM/NoTG groups, 3,718 probe sets were differentially expressed but these were over-represented in only 4 pathways. A classic accommodation phenotype was not identified. Using rt-PCR, the expression of inflammatory genes was significantly increased in +XM/TG+ recipients compared to control biopsies and to +XM/NoTG biopsies. In conclusion, pre-transplant DSA results in a gene expression profile characterized by inflammation and cellular infiltration and the majority of XM+ grafts are exposed to chronic injury. We analyzed gene expression from 2 groups of positive crossmatch kidney transplant recipients (+XM/TG+ and +XM/TG-). Patients in the +XM/TG+ group had 2 biopsies - prior to the development of transplant glomerulopathy on biopsy (Biopsy 1; cg=0; n=10) and after development of transplant glomerulopathy (Biopsy 2; cg>0; n=10). The +XM/TG- patients had only a Biopsy 2 (cg=0; n=11). A third patient group served as controls (n=10) and were from -XM recipients. This dataset is part of the TransQST collection.
Project description:The aim of this study was to investigate correlations between early subclinical findings (10 and 90 day histology and gene expression data) and late outcomes (transplant glomerulopathy and graft loss) in positive crossmatch kidney transplants (+XMKTx). Our goal was threefold: first, to confirm that intragraft molecular changes at 12m post-transplant are associated with the observed histologic changes in SLK transplant recipients, compared with KTA transplant recipients; second, to ascertain whether specific molecular pathways/markers that are not accounted for by routine histology are differentially expressed in the kidney allografts of the SLK transplant recipients; and third, to determine whether a molecular signature that is uniquely associated with simultaneous liver transplantation can be identified in kidney allografts. Biopsy samples were from positive and negative crossmatch simultaneous liver-kidney transplant recipients (12 month protocol biopsies) were compared to control patient (positive and negative crossmatch) biopsies obtained at 12 months. This dataset is part of the TransQST collection.
Project description:Treatment with angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) has been shown to have anti-inflammatory effects such as decreased growth factors and cytokines in animal models, this effect however, has not been investigated in kidney transplant recipients. We aimed to study the effect of ACEI or ARB treatment on intragraft gene expression profiles of transplant kidney biopsies using microarrays. Both groups had similar demographic characteristics in terms of age, race, sex, type of transplant, previous history of transplantation or acute rejection, panel reactive antibody levels, and immunosuppressive treatment. There were no differences in acute and chronic Banff allograft injury scores between the 2 Groups. Intragraft gene expression profiles of ACEI or ARB treated Group 2 biopsies showed decreased gene transcripts of interferon-gamma and rejection-associated transcripts (GRIT) and constitutive macrophage-associated transcripts (CMAT) compared to Group 1 biopsies. There were no statistically significant differences in expression of cytotoxic T cell (CAT), regulatory T cell (TREG), B-cell (BAT), natural killer cell (NKAT), or endothelial cell-associated transcripts (ENDAT) between the 2 Groups. Our data suggest that exposure to ACEI or ARB was associated with down-regulation of GRIT and CMAT. This anti-inflammatory effect of ACEI or ARB treatment could be an additional benefit in kidney transplant recipients.
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.
Project description:One and four month formalin-fixed paraffin embedded biopsies from 48 kidney transplant recipients (24 AKI donors, 24 non-AKI) underwent global gene expression profiling using DNA microarrays (96 arrays). At one month, there were 898 differentially expressed genes in the AKI group (p-value <0.005; FDR <10%), but by 4-months there were no longer any differences.
Project description:Treatment with angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) has been shown to have anti-inflammatory effects such as decreased growth factors and cytokines in animal models, this effect however, has not been investigated in kidney transplant recipients. We aimed to study the effect of ACEI or ARB treatment on intragraft gene expression profiles of transplant kidney biopsies using microarrays. Both groups had similar demographic characteristics in terms of age, race, sex, type of transplant, previous history of transplantation or acute rejection, panel reactive antibody levels, and immunosuppressive treatment. There were no differences in acute and chronic Banff allograft injury scores between the 2 Groups. Intragraft gene expression profiles of ACEI or ARB treated Group 2 biopsies showed decreased gene transcripts of interferon-gamma and rejection-associated transcripts (GRIT) and constitutive macrophage-associated transcripts (CMAT) compared to Group 1 biopsies. There were no statistically significant differences in expression of cytotoxic T cell (CAT), regulatory T cell (TREG), B-cell (BAT), natural killer cell (NKAT), or endothelial cell-associated transcripts (ENDAT) between the 2 Groups. Our data suggest that exposure to ACEI or ARB was associated with down-regulation of GRIT and CMAT. This anti-inflammatory effect of ACEI or ARB treatment could be an additional benefit in kidney transplant recipients. We identified 29 near normal biopsies with chronic sum allograft injury score (ct+ci+cv) ⤠3 for gene expression profiling comparing 2 groups; Group 1 (n=16), patients with no exposure of ACEI or ARB treatment and Group 2 patients (n=13) with exposure to ACEI or ARB at least 6 months prior to kidney biopsy. Biopsies with a diagnosis of acute or chronic rejection, recurrent or de novo glomerular disease, or polyoma nephropathy were excluded.
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:One and four month formalin-fixed paraffin embedded biopsies from 48 kidney transplant recipients (24 AKI donors, 24 non-AKI) underwent global gene expression profiling using DNA microarrays (96 arrays). At one month, there were 898 differentially expressed genes in the AKI group (p-value <0.005; FDR <10%), but by 4-months there were no longer any differences. One and four month formalin-fixed paraffin embedded (FFPE) biopsies from 48 kidney transplant recipients (24 AKI donors, 24 controls; 96 total samples) were profiled using Affymetrix U133PM Plus PM plate arrays on a GeneTitan MC instrument. All samples were selected from the SCD cohort only. AKI donor and controls samples were matched by date of transplantation. Total RNA was extracted from four 20-micron sections using Ambion RecoverAll Total Nucleic Acid Kit and processed for chip hybridization using the new Affymetrix SensationPlus™ FFPE Amplification and 3’ IVT Labeling kit according to the manufacturer’s protocol. Quantile data normalization by RMA and analysis was performed using Partek Genomics Suite for PDR-corrected differential gene expression by ANOVA. Pathway mapping was performed using Ingenuity Pathway Analysis (IPA). This dataset is part of the TransQST collection.
Project description:The Australian Chronic Allograft Dysfunction (AUSCAD) study is an ongoing single centre cohort study at Westmead hospital in Australia. In this section of the study, we aimed to identify biomarkers for allograft rejection in kidney transplant recipients, 3-months after their transplant. Our study recruited 123 patients, each having protocol renal allograft biopsies taken 3-months post transplantation.