ArrayExpress Uploader01611arrayexpress_sid3BACKGROUND: Assessment of gene expression in peripheral blood may provide a noninvasive screening test for allograft rejection. We...15583081E-GEOD-5967/profile/8773/arrayexpressuploader021heartintermediatelungperipheralDec.12, 2014Falsetranscription-profiling-of-human-peripheral-bloo-6E-GEOD-5967_A-AFFY-33Transcription profiling of human peripheral blood to detect cardiac allograft rejection and response to immunosuppressive therapyJun.19, 2014BACKGROUND: Assessment of gene expression in peripheral blood may provide a noninvasive screening test for allograft rejection. We hypothesized that changes in peripheral blood expression profiles would correlate with biopsy-proven rejection and would resolve after treatment of rejection episodes. METHODS AND RESULTS: We performed a case-control study nested within a cohort of 189 cardiac transplant patients who had blood samples obtained during endomyocardial biopsy (EMB). Using Affymetrix HU133A microarrays, we analyzed whole-blood expression profiles from 3 groups: (1) control samples with negative EMB (n=7); (2) samples obtained during rejection (at least International Society for Heart and Lung Transplantation grade 3A; n=7); and (3) samples obtained after rejection, after treatment and normalization of the EMB (n=7). We identified 91 transcripts differentially expressed in rejection compared with control (false discovery rate <0.10). In postrejection samples, 98% of transcripts returned toward control levels, displaying an intermediate expression profile for patients with treated rejection (P<0.0001). Cluster analysis of the 40 transcripts with >25% change in expression levels during rejection demonstrated good discrimination between control and rejection samples and verified the intermediate expression profile of postrejection samples. Quantitative real-time polymerase chain reaction confirmed significant differential expression for the predictive markers CFLAR and SOD2 (UniGene ID No. 355724 and No. 384944). CONCLUSIONS: These data demonstrate that peripheral blood expression profiles correlate with biopsy-proven allograft rejection. Intermediate expression profiles of treated rejection suggest persistent immune activation despite normalization of the EMB. If validated in larger studies, expression profiling may prove to be a more sensitive screening test for allograft rejection than EMB. Experiment Overall Design: Case- control study with three groups. Patients with rejection (r1-r7), follow-up samples after treatment of rejection (post1-7), and controls with no rejection (con1-7)http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-5967humanhttp://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-5967/samples/