Histologic and molecular patterns in responders and non-responders with chronic-active antibody mediated rejection
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ABSTRACT: Endothelial, inflammatory, cellular, interferon gamma and calcineurin inhibitor related genes were analyzed in 10 therapy responders and 6 non responders in chronic active antibody mediated rejection (caABMR) in kidney transplantation.
Project description:IntroductionThere is no proven therapy for chronic-active antibody-mediated rejection (caABMR), the major cause of late kidney allograft failure. Histological and molecular patterns associated with possible therapy responsiveness are not known.MethodsBased on rigorous selection criteria this single center, retrospective study identified 16 out of 1027 consecutive kidney transplant biopsies taken between 2008 and 2016 with pure, unquestionable caABMR, without other pathologic features. The change in estimated GFR pre- and post-biopsy/treatment were utilized to differentiate subjects into responders and non-responders. Gene sets reflecting active immune processes of caABMR were defined a priori, including endothelial, inflammatory, cellular, interferon gamma (IFNg) and calcineurin inhibitor (CNI) related-genes based on the literature. Transcript measurements were performed in RNA extracted from stored, formalin-fixed, paraffin-embedded (FFPE) samples using NanoString™ technology. Histology and gene expression patterns of responders and non-responders were compared.ResultsA reductionist approach applying very tight criteria to identify caABMR and treatment response excluded the vast majority of clinical ABMR cases. Only 16 out of 139 cases with a written diagnosis of chronic rejection fulfilled the caABMR criteria. Histological associations with therapy response included a lower peritubular capillaritis score (p = 0.028) along with less glomerulitis. In contrast, no single gene discriminated responders from non-responders. Activated genes associated with NK cells and endothelial cells suggested lack of treatment response.ConclusionIn caABMR active microvascular injury, in particular peritubular capillaritis, differentiates treatment responders from non-responders. Transcriptome changes in NK cell and endothelial cell associated genes may further help to identify treatment response. Future prospective studies will be needed which include more subjects, who receive standardized treatment protocols to identify biomarkers for treatment response.Clinical trial registration[ClinicalTrials.gov], identifier [NCT03430414].
Project description:Background: The benefit of extracorporeal photopheresis on the course of kidney transplant rejection is unknown. The aim of our study was to investigate the variations in transcriptomics on graft biopsies when extracorporeal photopheresis was used to treat chronic humoral rejection after kidney transplantation. Methods: we retrospectively analyzed the mRNA expression of 770 genes of interest in graft biopsies performed before and after treatment. Eight patients received an average of 23 extracorporeal photopheresis sessions over 4 months between the two biopsies. Results: Transcriptomic analysis of the graft biopsies identified a significant (adjusted p-value< 0.05) increase in CAV1 mRNA in all patients and a significant decrease in CD19, IL21, PAX5, and SFTPA2 mRNAs in 7 of 8 patients. Conclusions: In patients treated with extracorporeal photopheresis for chronic humoral rejection after renal transplantation, omic analysis of repeated biopsies shows a reduction in fibrotic and inflammatory transcriptomic signatures.
Project description:The enigmatic natural killer (NK) cells mediate spontaneous cell-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity via cell surface Fc receptors. The dual functionality of NK cells may enable their participation in chronic active antibody-mediated rejection (CA-ABMR), wherein evidence for complement activation is inconsistent. We RNA sequenced 57 human kidney allograft biopsies to determine whether NK cell cytotoxicity pathway gene set enrichment is an attribute of CA-ABMR. Among the 15,910 intragraft-expressed genes, 60 were uniquely overexpressed in CA-ABMR compared to active antibody-mediated rejection (active-ABMR) or acute T cell-mediated rejection (TCMR), versus no rejection (NR) biopsies. Cell type annotation showed enrichment for T cells and NK cells, and molecular pathways related to T cells and NK cells in CA-ABMR versus active-ABMR biopsies. NK cell cytotoxicity gene set enrichment in CA-ABMR than in ABMR biopsies, but not in TCMR, was confirmed by gene set variation analysis. Cellular deconvolution analysis divulged a higher proportion of NK cells in CA-ABMR compared to active-ABMR, but not in TCMR; immunohistochemistry of 138 consecutive clinically indicated allograft biopsies validated a higher proportion of CD56+ NK cells in CA-ABMR. Principal component analysis of deconvolved immune cell transcriptomes separated CA-ABMR and TCMR from active-ABMR and NR biopsies. NK cell cytotoxicity pathway gene set was found to be enriched in rejection compared to no rejection biopsies in two publicly available kidney allograft microarray datasets. Altogether, CA-ABMR is exemplified by the overexpression of the NK cell pathway, and, surprisingly, compared to active-ABMR, is exemplified by key gene sets that are similar to TCMR.
Project description:Previous studies of rejection-associated transcript expression in heart transplant biopsies identified not only rejection but a group of early biopsies with injury but no rejection. The present analysis used an expanded population of biopsies to explore parenchymal injury in all biopsies, with or without rejection, and its relationship to function, and outcome. Archetypal analysis defined five injury clusters: no-injury (N=376); mild (N=526); moderate (N=110); severe (N=87); and late (N=221). The late group, 62% of which had no rejection, had molecular characteristics associated with atrophy-fibrosis, depressed LVEF, and increased graft loss independent of rejection status. In random forest analysis, low LVEF was more strongly associated with injury scores than with rejection scores. Three-year graft failure was best predicted using a combination of injury and rejection scores. In heart transplant biopsies, injury-related molecular scores correlate with dysfunction and risk of failure and identify an important new group of late heart transplants, many with no rejection, that have impaired function and a high risk of graft loss. (ClinicalTrials.gov #NCT02670408).
Project description:Issues remain in the diagnosis of active antibody-mediated rejection (ABMR) in human kidney transplantation, as the hallmark criteria, the microcirculation inflammation scores and the C4d deposits, still lack reproducibility and sensitivity respectively. Using laser microdissection combined with mass spectrometry-based proteomics, this study presents the characterization of active antibody-mediated glomerular injuries, marked by evidences of leukocyte activation and migration, cellular stress through type I and II interferons and of microcirculation remodeling.
Project description:Chronic antibody-mediated rejection (CAMR) represents the main cause of kidney graft loss, but its pathogenesis is unclear. In order to uncover the molecular mechanisms underlying this condition, we characterized the molecular signature of circulating peripheral blood mononuclear cells and, separately, of CD4+ T lymphocytes isolated from CAMR patients compared to kidney transplant recipients with normal graft function and histology. In total peripheral lympho-monocytes, forty-five genes resulted differentially expressed between the two groups, most of them were up-regulated in CAMR and were involved in type I interferon signaling. In addition, in the same set of patients, 16 microRNAs resulted down-regulated in CAMR subjects compared to controls: 4 were predicted modulators of 6 mRNAs identified in the transcriptional analysis. In silico functional analysis supported the involvement of type I interferon signaling. To further confirm this hypothesis, we investigated the transcriptomic profiles of CD4+ T lymphocytes in an independent group of patients and we observed that the activation of type I interferon signaling was a specific hallmark of CAMR. In addition, in CAMR patients we detected a reduction of circulating BDCA2+ dendritic cells, the natural type I interferon- producing cells and their recruitment into the graft along with an increased expression of MXA, a type I interferon-induced protein, at tubulointerstitial and vascular level. In conclusion, our data suggest that type I interferon signaling may represent the molecular signature of CAMR. For microarray analysis, we studied 5 patients included into the control-group and 4 included into the study group. The control group was represented by renal transplant recipients undergoing protocol graft biopsies, with normal renal function and histology, in the absence of circulating anti-HLA antibodies. Study group patients showed clinical and histological evidence of CAMR according to Banff 2011 criteria.
Project description:Chronic antibody-mediated rejection (CAMR) represents the main cause of kidney graft loss, but its pathogenesis is unclear. In order to uncover the molecular mechanisms underlying this condition, we characterized the molecular signature of circulating peripheral blood mononuclear cells and, separately, of CD4+ T lymphocytes isolated from CAMR patients compared to kidney transplant recipients with normal graft function and histology. In total peripheral lympho-monocytes, forty-five genes resulted differentially expressed between the two groups, most of them were up-regulated in CAMR and were involved in type I interferon signaling. In addition, in the same set of patients, 16 microRNAs resulted down-regulated in CAMR subjects compared to controls: 4 were predicted modulators of 6 mRNAs identified in the transcriptional analysis. In silico functional analysis supported the involvement of type I interferon signaling. To further confirm this hypothesis, we investigated the transcriptomic profiles of CD4+ T lymphocytes in an independent group of patients and we observed that the activation of type I interferon signaling was a specific hallmark of CAMR. In addition, in CAMR patients we detected a reduction of circulating BDCA2+ dendritic cells, the natural type I interferon- producing cells and their recruitment into the graft along with an increased expression of MXA, a type I interferon-induced protein, at tubulointerstitial and vascular level. In conclusion, our data suggest that type I interferon signaling may represent the molecular signature of CAMR. For microarray analysis, we studied 8 patients included into the control-group and 10 included into the study group. The control group was represented by renal transplant recipients undergoing protocol graft biopsies, with normal renal function and histology, in the absence of circulating anti-HLA antibodies. Study group patients showed clinical and histological evidence of CAMR according to Banff 2011 criteria.
Project description:We used DNA microarrays (HG-U95Av2 GeneChips) to determine gene expression profiles for kidney biopsies and peripheral blood lymphocytes (PBLs) in transplant patients. Sample classes include kidney biopsies and PBLs from patients with 1) healthy normal donor kidneys, 2) well-functioning transplants with no clinical evidence of rejection, 3) kidneys undergoing acute rejection, and 4) transplants with renal dysfunction without rejection. Nomenclature for samples is as follows: 1) all sample names include either BX or PBL to indicate that they were derived from biopsies or PBLs respectively, 2) C indicates samples from healthy normal donors, 3) TX indicates samples from patients with well-functioning transplants with no clinical evidence of rejection, 3) AR indicates samples from transplant patients with kidneys undergoing acute rejection, 4) NR indicates samples from transplant patients with renal dysfunction without rejection. Abbreviations used to describe patient samples include the following: BX - Biopsy; PBL- Peripheral Blood Lymphocytes; CsA -Cyclosporine; MMF - Mycophenolate Mofetil; P - Prednisone; FK - Tacrolimus; SRL - Sirolimus; CAD -Cadaveric; LD - Live Donor; Scr - Serum Creatinine; ATN - Acute Tubular Necrosis CNI - Calcineurin Inhibitor; FSGS - Focal Segmental Glomerulosclerosis several array data sets did not pass quality control and were not analyzed. These include AR1PBL, NR4BX, and NR6PBL Keywords = DNA microarrays, gene expression, kidney, rejection, transplant Keywords: other. This dataset is part of the TransQST collection.