Cell-Free DNA to Detect Heart Allograft Acute Rejection

Abstract

Background: After heart transplantation, Endomyocardial biopsy (EMBx) is used to monitor for acute rejection (AR). Unfortunately, EMBx is invasive and its conventional histologic interpretation has limitations. This is a validation study to assesses the performance of a sensitive blood biomarker— percent donor-derived cell-free DNA (%ddcfDNA) — for detection of AR in cardiac transplant recipients. Methods: This multicenter, prospective cohort study recruited heart transplant subjects and collected plasma samples contemporaneously with EMBx for %ddcfDNA measurement by shotgun sequencing. Histopathology data was collected to define AR, its two phenotypes (acute cellular rejection, ACR, and antibody-mediated rejection, AMR) and controls without rejection. The primary analysis was to compare %ddcfDNA levels (median and interquartile range - IQR) for AR, AMR and ACR to controls and to determine %ddcfDNA test characteristics using receiver-operator characteristics analysis. Results: The study included 171 subjects with median post-transplant follow-up of 17.7 months (IQR: 12.1-23.6), with 1,392 EMBx, and 1,834 ddcfDNA measures available for analysis. Median %ddcfDNA levels decayed after surgery to 0.13% (0.03-0.21) by 28 days. %ddcfDNA increased again with AR compared to controls values (0.38, IQR=0.31-0.83, vs. 0.03, IQR=0.01-0.14 p<0.001). The rise was detected 0.5 and 3.2 months before histopathological diagnosis of ACR and AMR. The area-under-the- receiver-operator characteristics curve (AUROC) for AR was 0.92. A 0.25 %ddcfDNA threshold had a negative predictive value (NPV) for AR of 99% and would have safely eliminated 81% of EMBx. %ddcfDNA showed distinctive characteristics comparing AMR to ACR, included 5-fold higher levels (pAMR ≥2 1.68, IQR=0.49-2.79 vs. ACR grade ≥2R 0.34, IQR=0.28-0.72), higher AUROC (0.95 vs. 0.85), higher guanosine-cytosine content, and higher percentage of short ddcfDNA fragments. Conclusions: %ddcfDNA detected AR with a high AUROC and NPV. Monitoring with ddcfDNA, demonstrated excellent performance characteristics for both ACR and AMR and led to earlier detection than the EMBx-based monitoring. This study supports the use of %ddcfDNA to monitor for AR in heart transplant patients and paves the way for a clinical utility study. Clinical Trial Registration: URL: http://clinicaltrials.gov Unique Identifier: NCT02423070

Molecular Diagnosis of Rejection in Heart Transplantation

“…23 Figure 3 show the correlation of dd-cfDNA elevation with biopsy grades of ACR and AMR, as well as echocardiographic findings. 24 Another such commercially available assay is Prospera (Natera, San Carlos, CA, USA). Utilizing technology that was initially created to detect fetal cfDNA in prenatal testing, this test utilizes NSP-based PCR to measure dd-cfDNA for the detection of rejection.…”

“…Agbor-Enoh et al found that, for similar histopathologic grades, the percent dd-cfDNA was higher in AMR as compared with ACR, rose preceding the histologic diagnosis, and had a distinct fragment length with shorter fragments of cfDNA. 24 These unique insights can help facilitate more accurate diagnosis of AMR.…”

“…P values obtained by generalized estimating equation approach comparing all categories. Adapted with permission from Agbor-Enoh et al 24 LVEF, left ventricular ejection fraction. Rejection Diagnosis in Heart Transplant nosis of acute allograft rejection.…”

Donor-Derived Cell-Free DNA for Acute Rejection Monitoring in Heart and Lung Transplantation

“…Elevations in dd-cfDNA are also present in the setting of allograft injury in heart transplant recipients [32][33][34]. An early retrospective analysis of 7 heart transplant recipients performed by Snyder et al in 2011 demonstrated increases in dd-cfDNA in the setting of acute rejection with an AUC of 0.84 at a threshold of 1.7% for the detection of ≥ Grade 2R/3A ACR or AMR [35].…”

Expanding the Vision of Quality and Safety in Genomic Medicine

“…Ordering a genomic test is commonplace in oncology and becoming the standard of care for conditions from developmental disabilities to heart transplant rejection. 1,2 Over 26 million people in the USA have purchased a genomic test online with a growing proportion interested in their risk of common diseases like cancer, dementia, and heart disease. Given this exponential growth, it is time to expand the vision of genomic quality of care beyond the accuracy of genetic tests to include the clinical processes that determine how these tests are used.…”