Dataset Information

Progressive decline of function in renal allografts with normal 1-year biopsies: Gene expression studies fail to identify a classifier.

ABSTRACT: Histologic findings on 1-year biopsies such as inflammation with fibrosis and transplant glomerulopathy predict renal allograft loss by 5 years. However, almost half of the patients with graft loss have a 1-year biopsy that is either normal or has only interstitial fibrosis. The goal of this study was to determine if there was a gene expression profile in these relatively normal 1-year biopsies that predicted subsequent decline in renal function. Using transcriptome microarrays we measured intragraft mRNA levels in a retrospective Discovery cohort (170 patients with a normal/minimal fibrosis 1-year biopsy, 54 with progressive decline in function/graft loss and 116 with stable function) and developed a nested 10-fold cross-validated gene classifier that predicted progressive decline in renal function (positive predictive value = 38 ± 34%%; negative predictive value = 73 ± 30%, c-statistic = .59). In a prospective, multicenter Validation cohort (270 patients with Normal/Interstitial Fibrosis [IF]), the classifier had a 20% positive predictive value, 85% negative predictive value and .58 c-statistic. Importantly, the majority of patients with graft loss in the prospective study had 1-year biopsies scored as Normal or IF. We conclude predicting graft loss in many renal allograft recipients (i.e., those with a relatively normal 1-year biopsy and eGFR > 40) remains difficult.

SUBMITTER: Park WD

PROVIDER: S-EPMC8702476 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature

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Progressive decline of function in renal allografts with normal 1-year biopsies: Gene expression studies fail to identify a classifier.

Park Walter D WD Kim Dean Y DY Mai Martin L ML Reddy Kunam S KS Gonwa Thomas T Ryan Margaret S MS Herrera Hernandez Loren P LP Smith Maxwell L ML Geiger Xochiquetzal J XJ Turkevi-Nagy Sandor S Cornell Lynn D LD Smith Byron H BH Kremers Walter K WK Stegall Mark D MD

Clinical transplantation 20211109 12

Histologic findings on 1-year biopsies such as inflammation with fibrosis and transplant glomerulopathy predict renal allograft loss by 5 years. However, almost half of the patients with graft loss have a 1-year biopsy that is either normal or has only interstitial fibrosis. The goal of this study was to determine if there was a gene expression profile in these relatively normal 1-year biopsies that predicted subsequent decline in renal function. Using transcriptome microarrays we measured intra ...[more]

PMID: 34717009

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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: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.

Dataset Information

Progressive decline of function in renal allografts with normal 1-year biopsies: Gene expression studies fail to identify a classifier.

Publications

Progressive decline of function in renal allografts with normal 1-year biopsies: Gene expression studies fail to identify a classifier.

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