移植技术与研究

Technology-driven Performance Improvement of a Biomarker Panel in Kidney Transplant: OmniGraf

Abstract

Patricia M. West-Thielke, Cortney C. Miller, Winston Ally, April Sutton, Rohita Sinha, Mikaela Miller, Steve Kleiboeker and Juston C. Weems*

Here we present the impact of the transition from TruGraf microarray to TruGraf PCR on the performance of OmniGraf, the combination of TruGraf Gene expression and TRAC dd-cfDNA tests. Using the same biopsy-paired samples as previously published, we saw an improvement in the NPV from 88% to 94% when both assays were negative. Perhaps more importantly, we observed an increase in the PPV from 81% to 89% when both tests were positive. False negative results were reduced from 31% to 17%, while true negative results improved from 74% to 81%. Within our cohorts, we observed 26.2% of results to be positive for one test and negative for the other: 11.7% showed elevated TRAC (+) and a negative TruGraf (-); 14.5% showed a TruGraf positive (+) and low TRAC score (-). The previous publication demonstrated that TruGraf microarray was significantly better at detecting subclinical TCMR and TRAC was significantly better at detecting subclinical ABMR, highlighting the importance of the combination of the tests.  The methodological improvement in TruGraf technology increased its detection of both TCMR and ABMR subtypes of rejection, leading to a higher NPV and PPV. In the field of transplant biomarkers, where high NPV values have been the focus, we present novel clinical validation data on the first commercial biomarker panel with a high PPV. With the data presented here, OmniGraf results provide a high probability of either immune quiescence or subclinical rejection to support clinical decision-making.