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[Show abstract][Hide abstract] ABSTRACT: Lung transplantation is effective for many diseases that are unresponsive to other therapy. However, long-term survival of recipients is limited by the development of bronchiolitis obliterans syndrome. Acute rejection is a major risk factor for bronchiolitis obliterans syndrome, but noninvasive biomarkers have not been identified. To address this deficiency, gene expression microarrays were performed using bronchoalveolar lavage cells of lung transplant recipients with acute rejection (n = 7) and with no rejection (n = 27). The cell and differential counts were similar. Signal values for genes between groups were compared using t tests. One hundred thirty-five genes were upregulated in the acute-rejection group, including genes involved in acute rejection, immune response genes with an unknown role in rejection, genes not known to have a role in rejection, and genes of unknown function. Two-dimensional hierarchical clustering grouped all acute rejection samples into one cluster and the majority of the no-rejection samples into a second cluster. The acute-rejection samples showed significant changes in gene expression for seven biological pathways. Bronchoalveolar lavage cells are a reliable RNA source for microarray analysis, which is powerful in identifying acute-rejection genes. The individual genes, patterns of gene expression, or biologic pathways identified may represent novel biomarkers for acute rejection.
Full-text · Article · Dec 2003 · American Journal of Respiratory and Critical Care Medicine
[Show abstract][Hide abstract] ABSTRACT: Apoptosis mediated by the Fas/Fas ligand (FasL) has been implicated in rejection of solid organ allografts and it has been recently proposed that soluble forms of Fas could interfere with this interaction, blocking apoptosis. The purpose of this study was to analyze intragraft Fas, FasL, and soluble Fas mRNA levels in relation to acute rejection in cardiac allografts in humans. mRNA levels were determined by quantitative reverse transcriptase-polymerase chain reaction in 42 samples of endomyocardial biopsies obtained from 18 cardiac transplant recipients within the first 6 months after transplantation. FasL and Fas mRNA levels were higher in biopsies with rejection than in biopsies without rejection, and no difference was observed in soluble Fas mRNA. During rejection, there was a positive correlation between the mRNA levels of Fas-FasL, Fas-soluble Fas, and FasL-soluble Fas. During quiescent periods, however, the only correlation observed was between Fas and soluble Fas mRNA levels. In conclusion, our findings do not suggest a role for soluble Fas, confirm the heightened expression of FasL, and indicate, for the first time, an increased expression of Fas in acute rejection of cardiac allografts.
No preview · Article · Feb 2006 · Human Immunology
[Show abstract][Hide abstract] ABSTRACT: Gene expression microarrays can estimate the prevalence of mRNA for thousands of genes in a small sample of cells or tissue. Organ transplant researchers are increasingly using microarrays to identify specific patterns of gene expression that predict and characterize acute and chronic rejection, and to improve our understanding of the mechanisms underlying organ allograft dysfunction. We used microarrays to assess gene expression in bronchoalveolar lavage cell samples from lung transplant recipients with and without acute rejection on simultaneous lung biopsies. These studies showed increased expression during acute rejection of genes involved in inflammation, apoptosis, and T-cell activation and proliferation. We also studied gene expression during the evolution of airway obliteration in a murine heterotopic tracheal transplant model of chronic rejection. These studies demonstrated specific patterns of gene expression at defined time points after transplantation in allografts, whereas gene expression in isografts reverted back to that of native tracheas within 2 wk after transplantation. These studies demonstrate the potential power of microarrays to identify biomarkers of acute and chronic lung rejection. The application of new genetic, genomic, and proteomic technologies is in its infancy, and the microarray-based studies described here are clearly only the beginning of their application to lung transplantation. The massive amount of data generated per tissue or cell sample has spawned an outpouring of invention in the bioinformatics field, which is developing methodologies to turn data into meaningful and reproducible clinical and mechanistic inferences.
Full-text · Article · Feb 2007 · Proceedings of the American Thoracic Society