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: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.
Project description:To ensure safety tolerance induction protocols are accompanied by conventional immunosuppressive drugs IS. But IS such as calcineurin inhibitors CNI can interfere with tolerance induction. We investigated the effect of an additional CNI treatment on anti-CD4 mAb-induced tolerance induction upon rat kidney transplantation. Additional CNI treatment induced deteriorated graft function and chronic rejection characterised by alloantibody production, intragraft plasma cells and C3d deposition. Microarray analysis revealed enhanced intragraft expression of the B cell chemokine CXCL13 upon additional CNI treatment. In contrast PNOC, a B cell-related gene highly expressed in operational tolerant kidney transplant recipients, was decreased in grafts of anti-CD4 mAb+CsA-treated recipients suggesting an altered balance of B regulatory genes. Transient B cell depletion or transfer of Tregs three weeks after transplantation could inhibit intragraft B cell accumulation, alloantibody production and ameliorate chronic rejection. These data represent unexpected findings and should be taken into consideration when designing new clinical trials. To safe the benefit of CNI in controlling memory T cell responses we need strategies for a therapeutic optimization. We show here that early B cell depletion or transfer of Tregs may be one approach to arrest B cell accumulation, activation and graft destruction. comparative analysis of different immunosuppressive regimens on renal allograft gene expression versus untreated allografts
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:CONTEXT Slowly progressive chronic tubulo-interstitial damage jeopardizes long-term renal allograft survival. Both immune and non-immune mechanisms are thought to contribute, but the most promising targets for timely intervention have not been identified. OBJECTIVE In the current study we seek to determine the driving force behind progressive histological damage of renal allografts, without the interference of donor pathology, delayed graft function and acute graft rejection. DESIGN We used microarrays to examine whole genome expression profiles in renal allograft protocol biopsies, and analyzed the correlation between gene expression and the histological appearance over time. The gene expression profiles in these protocol biopsies were then compared with gene expression of biopsies with acute T-cell mediated rejection. PATIENTS Human renal allograft biopsies (N=120) were included: 96 rejection-free protocol biopsies and 24 biopsies with T-cell mediated acute rejection. RESULTS In this highly cross-validated study, we demonstrate the significant association of established, ongoing and future chronic histological damage with regulation of adaptive immune gene expression (T-cell and B-cell transcript sets) and innate immune response gene expression (dendritic cell, NK-cell, mast cell and granulocyte transcripts). We demonstrate the ability of gene expression analysis to perform as a quantitative marker for ongoing inflammation with a wide dynamic range: from subtle subhistological inflammation prior to development of chronic damage, over moderate subclinical inflammation associated with chronic histological damage, to marked inflammation of Banff-grade acute T-cell mediated rejection. CONCLUSION Progressive chronic histological damage after kidney transplantation is associated with significant regulation of both innate and adaptive immune responses, months before the histological lesions appear. This study therefore corroborates the hypothesis that quantitative inflammation below the diagnostic threshold of classic T-cell or antibody-mediated rejection is associated with early subclinical stages of progressive renal allograft damage. We used microarrays to examine whole genome expression profiles in renal allograft protocol biopsies, and analyzed the correlation between gene expression and the histological appearance over time. The gene expression profiles in these protocol biopsies were then compared with gene expression of biopsies with acute T-cell mediated rejection. Human renal allograft biopsies (N=120) were included: 96 rejection-free protocol biopsies and 24 biopsies with T-cell mediated acute rejection.
Project description:We performed a global gene expression analysis comparing intragraft tolerant CD8+ T cells from CD3 antibody-treated mice showing permanent islet graft survival to intra-graft effector CD8+ T cells isolated from untreated mice showing acute rejection of islet allografts. The objective was to emphasize the anergic profile of CD8+ T cells residing within the pancreatic islet allograft of mice rendered tolerant following CD3 antibody therapy.
Project description:Introduction. Factors contributing to kidney transplant fibrosis remain incompletely understood—particularly in the absence of acute complications. Methods. Baseline and one-year surveillance biopsies from 15 uncomplicated living donor kidney transplants were subjected to microarray and quantitative RT-PCR (qRT-PCR) analyses in order to examine changes in gene expression patterns over time. Biopsy pairs were purposefully selected from allografts with no history of acute complications and were divided into those that were histologically normal (n = 7) and those that had developed subclinical interstitial fibrosis (n = 8) at 1 year. Results. Compared to the paired baseline specimens, expression levels of 3578 probesets were found altered in all the one-year biopsies studied. A large proportion of the upregulated genes in this transplant-associated profile were functionally linked with inflammation, immunity or response to injury. These included components of inflammation-related signaling pathways (integrin, interferon and TLR) as well as individual mediators of inflammatory and immune responses. An additional 2884 probesets demonstrated altered expression in fibrotic grafts only at 1 year. The gene products in this fibrosis-associated profile were also predominantly linked with inflammation and immune function, suggesting exaggerated inflammatory activity within the fibrotic grafts. qRT-PCR analyses confirmed the predicted expression patterns for selected transcripts from the microarray profiles. Conclusions. Transcriptional profiles of histologically normal living donor renal allografts indicate that there is ongoing injury response and inflammation at 1 year compared to the immediate post-transplant period. Subclinical development of interstitial fibrosis during the first post-transplant year is associated with additional upregulation of inflammation-related genes. Keywords: time course, comparative expression We analyzed gene expression from a group of 15 renal transplant patients. All patients had histologically normal time zero biopsy but while 7 remained histologically normal (TxNorm), 8 developed subclinical interstitial fibrosis (GIF/TA) by 1 year. Patient groups were carefully selected to include patients on the same immunosuppresion therapy, transplant type, biopsy histology and absence of overt post-transplant complications (acute rejection, BK, etc). This dataset is part of the TransQST collection.
Project description:Acute rejection of human allografts has been viewed mostly through the lens of adaptive immunity, and the intragraft landscape of innate immunity genes has not been characterized in an unbiased fashion. We did RNA sequencing of 34 kidney allograft biopsy specimens from 34 adult recipients; 16 were categorized as Banff acute T-cell mediated rejection (TCMR) and 18 as normal. Computational analysis of intragraft mRNA transcriptome identified significantly higher abundance of mRNA for pattern recognition receptors in TCMR compared to normal biopsies, as well as increased expression of mRNAs for cytokines, chemokines, interferons, and caspases. Intragraft levels of calcineurin mRNA were higher in TCMR biopsies suggesting under immunosuppression compared to normal biopsies. Cell-type enrichment analysis revealed higher abundance of dendritic cells and macrophages in TCMR biopsies. Damage associated molecular patterns, the endogenous ligands for pattern recognition receptors, as well markers of DNA damage were higher in TCMR. mRNA expression patterns supported increased calcium flux and indices of endoplasmic, cellular oxidative, and mitochondrial stress were higher in TCMR. Expression of mRNAs in major metabolic pathways were decreased in TCMR. Our global and unbiased transcriptome profiling identified heightened expression of innate immune system genes during an episode of TCMR in human kidney allografts.