Absolute quantification of donor-derived cell-free DNA as a marker of rejection and graft injury in kidney transplantation: Results from a prospective observational study

Am J Transplant. 2019 Nov;19(11):3087-3099. doi: 10.1111/ajt.15416. Epub 2019 May 28.


Donor-derived cell-free DNA (dd-cfDNA) is a noninvasive biomarker for comprehensive monitoring of allograft injury and rejection in kidney transplantation (KTx). dd-cfDNA quantification of copies/mL plasma (dd-cfDNA[cp/mL]) was compared to dd-cfDNA fraction (dd-cfDNA[%]) at prespecified visits in 189 patients over 1 year post KTx. In patients (N = 15, n = 22 samples) with biopsy-proven rejection (BPR), median dd-cfDNA(cp/mL) was 3.3-fold and median dd-cfDNA(%) 2.0-fold higher (82 cp/mL; 0.57%, respectively) than medians in Stable Phase patients (N = 83, n = 408) without rejection (25 cp/mL; 0.29%). Results for acute tubular necrosis (ATN) were not significantly different from those with biopsy-proven rejection (BPR). dd-cfDNA identified unnecessary biopsies triggered by a rise in plasma creatinine. Receiver operating characteristic (ROC) analysis showed superior performance (P = .02) of measuring dd-cfDNA(cp/mL) (AUC = 0.83) compared to dd-cfDNA(%) (area under the curve [AUC] = 0.73). Diagnostic odds ratios were 7.31 for dd-cfDNA(cp/mL), and 6.02 for dd-cfDNA(%) at thresholds of 52 cp/mL and 0.43%, respectively. Plasma creatinine showed a low correlation (r = 0.37) with dd-cfDNA(cp/mL). In a patient subset (N = 24) there was a significantly higher rate of patients with elevated dd-cfDNA(cp/mL) with lower tacrolimus levels (<8 μg/L) compared to the group with higher tacrolimus concentrations (P = .0036) suggesting that dd-cfDNA may detect inadequate immunosuppression resulting in subclinical graft damage. Absolute dd-cfDNA(cp/mL) allowed for better discrimination than dd-cfDNA(%) of KTx patients with BPR and is useful to avoid unnecessary biopsies.

Keywords: biomarker; clinical decision-making; clinical research/practice; immunosuppressant; immunosuppression/immune modulation; kidney failure/injury; kidney transplantation/nephrology; rejection.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / analysis*
  • Cell-Free Nucleic Acids / analysis
  • Cell-Free Nucleic Acids / genetics*
  • Female
  • Follow-Up Studies
  • Graft Rejection / diagnosis*
  • Graft Rejection / etiology
  • Graft Rejection / pathology
  • Graft Survival
  • Humans
  • Kidney Failure, Chronic / surgery*
  • Kidney Transplantation / adverse effects*
  • Male
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • ROC Curve
  • Risk Factors
  • Tissue Donors / supply & distribution*


  • Biomarkers
  • Cell-Free Nucleic Acids