Project description:The significance of borderline changes (BL) in kidney allograft biopsies is widely debated. We examined differences in gene expression patterns between early clinical biopsy tissue and 3-month protocol biopsy tissue, all of which had histological BL changes and identified specific molecular BL patterns associated with poor graft outcome. The expression profiles were analyzed in training set of patients and next data were validated in validation cohort using RT-qPCR. Using the Illumina microarray technology, we observed greater expression of immunity- and inflammation-related genes in tissues from early clinical biopsies compared to 3-month protocol biopsies with BL findings. In tissues with early clinically manifested BL changes, graft deterioration within 24 months due to chronic rejection was associated with increased activation of immune, defense, and inflammatory processes, specifically with higher donor age and expression of macrophage receptor CLEC5A. In the 3-month protocol biopsies with BL changes, graft dysfunction was associated with increased expression of fibrinogen complex transcripts. This study highlights the molecular differences between clinical and subclinical biopsies with similar histological findings. The data also support a recommendation for frequent patient monitoring, especially in those who received grafts from expanded criteria donors (ECDs). The experiments were performed with total RNA derived from the renal graft biopsy samples of 28 different patients who had undergone a kidney transplantation. Only the patients with diagnosis of borderline changes early (M-bM-^IM-$2 months) or protocolar (3 months) were included in the study. RNA profiles of patients with stable and deteriorated graft function during 2 years after transplantation were compared. As microarray platform, Illumina HumanHT-12 v4.0 Expression BeadChips (Illumina) was used. The chip scanning was performed with a BeadStation 500 instrument (Illumina Inc), and the raw data were extracted with the BeadStudio Data Analysis Software (Illumina). The R software lumi package was used to further process the raw data. The quantile method was used for normalization.

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: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.

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A peripheral blood gene expression signature diagnoses subclinical acute rejection [validation]

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