Quantification of Circulating Donor Specific Cell Free DNA Is an Exquisitely Sensitive Non-Invasive Indicator of Injury to the Donor Heart

Abstract

Purpose The detection and quantification of circulating donor specific cell free DNA (DS cf-DNA) has been proposed as a non-invasive biomarker for the detection of rejection following cardiac transplantation. The purpose of this study was to investigate the sensitivity of a novel approach based on targeted quantification of DS cf-DNA in detecting injury to the donor organ. Methods and Materials A prospective blinded study was conducted in 45 samples from 17 pediatric patients post heart transplantation. In 11 patients, blood samples were drawn at each of three time points: 1) 14 to 36 hours, 2) 84-126 hours, and 3) 160-206 hours post cross clamp removal (33 samples). In 6 patients samples were drawn both immediately before and within 35 min following standard bioptome surveillance cardiac biopsy (12 samples). Total cf-DNA was determined by quantitative real time PCR; percent donor specific DNA was measured using targeted next generation sequencing (DANSRtm, Ariosa Diagnostics). Results All 11 patient samples were elevated on post op time 1 compared to times 2 and 3 (p figure ). All 6 patient samples were at baseline levels at time of surveillance biopsy. All surveillance biopsies were negative for rejection. All 6 post bioptome biopsy samples were significantly elevated compared to their pre biopsy levels (p figure ). Conclusions Circulating levels of DS cf-DNA are elevated post clamp removal and decrease to baseline within 5 days. The sensitivity of the approach allows unambiguous detection of myocardial injury at the level of that produced by standard surveillance biopsy. Quantification of circulating DS cf-DNA may be a sensitive non-invasive biomarker for rejection.