BioProject

Liver transplantation is the only lifesaving therapy for patients with irreversible liver failure, and 30% of the recipients experience acute rejection in the first 12 months following transplantation. Acute rejection is diagnosed by core needle biopsy and noninvasive methods for predicting acute rejection could improve clinical care. MicroRNAs (miRNAs) are emerging as biomarkers of clinically significant events. We investigated whether circulating extracellular miRNA profiles in sera matched to liver allograft biopsies predict human liver allograft status. Small RNA sequencing and TaqMan low-density array analysis of RNA from biopsy matched sera identified that liver specific miR-122, and miRs -885, -210, -194, 193b, -192, -148a, -34a and -22 distinguish patients with acute rejection biopsies from those with biopsies without rejection features (false discovery rate of <0.15). We measured absolute levels of these informative 9 miRNAs using quantitative real-time PCR assays. Receiver-operating-characteristic (ROC) curve analysis of circulating levels of miRNA levels validated that all 9 miRNAs discriminate patients with acute rejection in their biopsies from those without rejection in their biopsies (P <0.01 to P<0.0001). A parsimonious diagnostic signature of miR-122 and miR-194 was diagnostic of acute rejection with a sensitivity of 79% (95% confidence interval [CI], 49% to 95%) and a specificity of 88% (95% CI, 64% to 99%) (area under the curve, 0.91; 95% CI, 0.81 to 1.00; P<0.001 by ROC curve analysis). Our findings suggest that a molecular signature of miR-122 and miR-194 in serum offers a noninvasive means of diagnosing acute rejection including mild forms in human liver allografts. Overall design: Total RNA was isolated from serum of patients after liver allograft transplantation (Clinical Trials of Transplantation-07 Study. A primary objective of the National Institutes of Health sponsored Clinical Trials in Organ Transplantation-07 observational study; CTOT-07 Study, ClinicalTrials.gov identifier: NCT01428700) and used for miRNA-sequencing and qPCR analysis.