Histologic diagnosis of T cell-mediated rejection in kidney transplant biopsies has limited reproducibility because it is based on non-specific lesions using arbitrary rules that are subject to differing interpretations. We used microarray results from 403 indication biopsies previously given histologic diagnoses to develop a molecular classifier that assigned a molecular T cell-mediated rejection score to each biopsy. Independent assessment of the biopsies by multiple pathologists confirmed considerable disagreement on the presence of TCMR features: 79-88% accuracy and 35-69% sensitivity. The agreement of the molecular T cell-mediated rejection score with the histology diagnosis was similar to agreement among individual pathologists: accuracy 89%, sensitivity 51%. However, the score also predicted the consensus among pathologists, being highest when all agreed. Many discrepancies between the scores and the histologic diagnoses were in situations where histology is unreliable e.g. scarred biopsies. The score correlated with histologic lesions and gene sets associated with T cell-mediated rejection. The transcripts most often selected by the classifier were expressed in effector T cells, dendritic cells, or macrophages or inducible by interferon-gamma. Thus the T cell-mediated rejection score offers an objective assessment of kidney transplant biopsies, predicting the consensus opinion among multiple pathologists, and offering insights into underlying disease mechanisms.
Molecular diagnosis of T cell-mediated rejection in human kidney transplant biopsies.
Disease
View SamplesThe authors report that in INTERCOM, a prospective international study of 300 kidney transplant biopsies, a microarray-based molecular score for T cell-mediated rejection changed the assessment of 26% of all biopsies, illustrating the potential of precision diagnostics to impact practice.
Potential impact of microarray diagnosis of T cell-mediated rejection in kidney transplants: The INTERCOM study.
Specimen part
View SamplesWe have observed that follicular B cells from mice with a hypomorphic mutation (IkL/L) in the Ikzf1 gene (which encodes the Ikaros transcription factor) exhibit an increased proliferative response to anti-IgM stimulation (Kirstetter et al, Eur J Immunol, 32:720-30, 2002). We asked if Ikaros controls the transcriptional response that unfolds after activation, or if differences in the transcriptional landscape of resting B cells could explain the altered response. To this end, we have determined the transcriptome of unstimulated WT and IkL/L follicular B cells, as well as that of cells stimulated for 3h and 12h with anti-IgM. Samples from 2 independent experients were analyzed.
Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways.
Age, Specimen part
View SamplesMicroarray analysis of human kidneys with acute kidney injury (AKI) has been limited because such kidneys are seldom biopsied. However, all kidney transplants experience AKI, and early kidney transplants without rejection are an excellent model for human AKI: they are screened to exclude chronic kidney disease, frequently biopsied, and have extensive follow-up. We used histopathology and microarrays to compare indication biopsies from 28 transplants with AKI to 11 pristine protocol biopsies of stable transplants. Kidneys with AKI showed increased expression of 394 injury-repair response associated transcripts, including many known epithelial injury molecules (e.g. ITGB6, LCN2), tissue remodeling molecules (e.g. VCAN), and inflammation molecules (S100A8, ITGB3). Many other genes also predict the phenotype, depending on statistical filtering rules, including AKI biomarkers as HAVCR1 and IL18. Most mouse orthologs of the top injury-repair transcripts were increased in published mouse AKI models. Pathway analysis of the injury-repair transcripts revealed similarities to cancer, development, and cell movement. The injury-repair transcript score AKI kidneys correlated with reduced function, future recovery, brain death, and need for dialysis, but not future graft loss. In contrast, histologic features of "acute tubular injury" did not correlate with function or with the molecular changes. Thus the injury-repair associated transcripts represent a massive coordinate injury-repair response of kidney parenchyma to AKI, similar to mouse AKI models, and provide an objective measure for assessing the severity of AKI in kidney biopsies and validation for the use of many AKI biomarkers.
Molecular phenotypes of acute kidney injury in kidney transplants.
Specimen part, Disease
View SamplesThe experiment aimed at determining the genes that are under the control of the Ikaros transcription factor in mouse splenic B1 and B2 B lymphocyte subsets. To this aim, we used Ikf/f R26-CreERT2+ (Cre+) or Ikf/f R26-CreERT2- (Cre-) mice, which correspond to mice with floxed null alleles for Ikzf1 (Heizmann et al., JEM 210:2823-32, 2013) that were crossed with the R26-CreERT2 mice, which harbor a knock-in of the cDNA encoding the tamoxifen (TAM) inducible CreERT2 recombinase in the Rosa26 gene (Badea et al, J. Neurosci 23:2314-22, 2003). 6-8 week-old mice were injected daily with TAM for 3d (50mg/kg). Mice were sacrificed 10d after the first injection, and splenic B1 and B2 B cell populations sorted by flow cytometry.
Ikaros Is a Negative Regulator of B1 Cell Development and Function.
Sex, Specimen part
View SamplesHere we describe microRNA profiling of a single differentiation pathway from the stem cell through to terminally differentated mature cells. Overall design: Populations corresponding to distinct stages in T lymphocyte development, from the hematopoietic stem cell-enriched Lin-Sca+Kit+ population through to mature CD4+ and CD8+ T cells were FACS-sorted to purity from the bone marrow and thymus of C57BL/6 mice. Total RNA was extract from each population from which microRNA sequencing libraries were constructed.
Dynamic microRNA gene transcription and processing during T cell development.
Specimen part, Cell line, Subject
View SamplesHere we show the microRNA genes can been very large and displaying many summarizing structural characteristics Overall design: MicroRNA biogenesis was ablated in CD4+ and CD8+ by deleted Rnasen gene (encoding Drosha). Poly A RNAs were extracted and analyzed by ultra high throughput sequencing
Dynamic microRNA gene transcription and processing during T cell development.
Specimen part, Cell line, Subject
View SamplesDendritic cells (DCs) are a complex group of cells which play a critical role in vertebrate immunity. Spleen or lymph node resident DCs are subdivided into conventional DC (cDC) subsets (CD11b and CD8alpha in mouse; BDCA1 and BDCA3 in man) and plasmacytoid DCs (pDCs). It is currently unclear if these various DC populations belong to a unique hematopoietic lineage and if the subsets identified in the mouse and human systems are evolutionary homologs. To bring novel insights into these questions, we sought conserved genetic signatures for these DCs through the analysis of a compendium of genome-wide expression profiles of mouse or human leukocytes.
Novel insights into the relationships between dendritic cell subsets in human and mouse revealed by genome-wide expression profiling.
No sample metadata fields
View SamplesThe experiment was to compare leukemic T cells from thymic lymphomas from homozygote mice for the IkL/L hypomorphic mutation and non-transformed thymocytes, either of WT or IkL/L genotype. The aim was to identify a gene expression signature specific to the IkL/L tumors.
Notch activation is an early and critical event during T-Cell leukemogenesis in Ikaros-deficient mice.
No sample metadata fields
View SamplesThe gene encoding a protein (AmGSTF1) associated with multiple herbicide resistance (MHR) in black-grass was transgenically expressed in Arabidopsis thaliana.The goal of this study was to determine if AmGSTF1 could elicit an MHR phenotype in the transgenic host.
Key role for a glutathione transferase in multiple-herbicide resistance in grass weeds.
Specimen part
View Samples