Project description:Background: Hepatitis E Virus (HEV) is a new causative agent of chronic hepatitis in solid organ transplant recipients in Europe. Factors associated with the occurrence and persistence of chronic HEV infection remain largely unknown but chronic evolution seems to be the consequence of hostM-bM-^@M-^Ys immunological factors rather than of viral factors. Method: In a prospective case-control study, we have determined in whole blood of chronically HEV-infected kidney-transplant recipients the host response using microarray technology. Results: Chronically HEV-infected kidney-transplant recipients exhibited a specific transcriptional program, in which interferon effectors were prominent. The intensity of expression of each signatureM-bM-^@M-^Ys gene was significantly lower in patients who were subsequently cleared of HEV than in patients who were not. Furthermore, in patients who were cleared of HEV, a higher expression of these genes was associated with a longer delay until HEV clearance. Conclusions: The specific transcriptional program determined in chronically HEV-infected kidney-transplant recipients suggests an activation of type I interferon response. Intensity of interferon-stimulated genes expression could be useful to forecast the outcome of infection. High expression of interferon-stimulated genes could signify a dysregulation in the interferon response that might favour the persistence of the HEV infection. TrialM-bM-^@M-^Ys registration number: NCT01090232; RegistryM-bM-^@M-^Ys URL: http://clinicaltrials.gov/ct2/show/study/NCT01090232?term=kidney+transplant+recipients&cntry1=EU%3AFR&rank=2 Total RNA was extracted from whole-blood sample or monocytes of kidney-transplant patients with or without chronic hepatitis E (CHE) infection. Control patients were matched up with CHE patients for age, sex, time since kidney transplant and immunosuppressive treatment.
Project description:Background: Hepatitis E Virus (HEV) is a new causative agent of chronic hepatitis in solid organ transplant recipients in Europe. Factors associated with the occurrence and persistence of chronic HEV infection remain largely unknown but chronic evolution seems to be the consequence of host’s immunological factors rather than of viral factors. Method: In a prospective case-control study, we have determined in whole blood of chronically HEV-infected kidney-transplant recipients the host response using microarray technology. Results: Chronically HEV-infected kidney-transplant recipients exhibited a specific transcriptional program, in which interferon effectors were prominent. The intensity of expression of each signature’s gene was significantly lower in patients who were subsequently cleared of HEV than in patients who were not. Furthermore, in patients who were cleared of HEV, a higher expression of these genes was associated with a longer delay until HEV clearance. Conclusions: The specific transcriptional program determined in chronically HEV-infected kidney-transplant recipients suggests an activation of type I interferon response. Intensity of interferon-stimulated genes expression could be useful to forecast the outcome of infection. High expression of interferon-stimulated genes could signify a dysregulation in the interferon response that might favour the persistence of the HEV infection. Trial’s registration number: NCT01090232; Registry’s URL: http://clinicaltrials.gov/ct2/show/study/NCT01090232?term=kidney+transplant+recipients&cntry1=EU%3AFR&rank=2
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: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: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: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. We performed microarray experiments in CD4+ T cells isolated from a small independent group of 5 patients included into the control-group and 5 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:Tacrolimus (Tac) is an effective anti-rejection agent in kidney transplantation, but its off-target effects make withdrawal desirable. While studies indicate that Tac can be safely withdrawn in a subset of kidney transplant recipients, immune mechanisms that underlie successful vs. unsuccessful Tac removal are unknown. We performed microarray analyses of PBMC RNA from subjects enrolled in the Clinical Trials in Organ Transplantation-09 study in which stable kidney transplant recipients were randomized to Tac withdrawal or maintenance of standard immunosuppression beginning 6-mo post-transplant. Eight of 14 subjects attempted but failed withdrawal, while six developed stable graft function for ≥2 years on mycophenolate mofetil plus prednisone. Whereas failed withdrawal upregulated immune activation genes, successful Tac withdrawal was associated with a distinct, T cell-specific, downregulatory, and pro-apoptotic gene program. Functional analyses suggested stronger donor-reactive immunity in subjects who failed withdrawal without evidence of regulatory T cell dysfunction. Together, our data suggest that successful Tac withdrawal can unleash an active, protective pro-apoptotic T cell program, and provide the foundation for developing strategies to promote this protective immunological phenotype in kidney transplant recipients.
Project description:Operational tolerance after solid organ transplantation is defined as stable graft acceptance without immunosuppression while maintaining normal immunocompetence against immunological insults. However, it is not clear yet which cellular and molecular pathways are driving tolerance in these patients and how this state can be induced in order to improve graft survival. Several transcriptomic analysis have shown that transcription signatures in blood can reflect the immunological state associated with operational tolerance in kidney transplant. Nonetheless, epigenetic dynamics orchestrating these transcription signatures have not yet been studied. Here, we performed genome-wide analysis of DNA methylation of kidney transplant recipients with chronic rejection and operational tolerance. Our data showed that chronic rejection and operational tolerance recipients have differential DNA methylation in 2737 genes, indicating that each patient group has a specific epigenetic signature associated with transplant outcome. In addition, we observed that operational tolerance is associated with DNA demethylation in genes involved in immune function, including B cell activation (e.g. ST6GAL1, MS4A1 and MEF2C) and the Th17 differentiation program (e.g. LY9 and BATF), while in CR patients is mostly associated intracellular signaling and ubiquitination pathways. Finally, we used weighted gene co-expression network analysis (WGCNA) to select the more defining epigenetic changes associated with operational tolerance. By this method, we select 12 genomic regions specifically hypomethylated (HIVEP2, HOMER1, UTRN, PTPRO, SP100 and JAZF1) or hypermethylated (EMZ8, EZR-AS, WDR20, NADSYN1, TBCD and MED17) in tolerant patients. Analysis of these genes in stable transplant recipients with immunosuppression showed that these patients have a similar methylation signature to operational tolerance recipients. Overall, these results demonstrate that DNA methylation in blood can mirror the immune status associated with kidney transplant outcome and provides a starting point for understanding the epigenetic mechanisms associated with operational tolerance.