Donor-Derived Cell-Free DNA Performance Characteristics are Similar for Repeat and Primary Kidney Transplant Recipients
1California Pacific Medical Center, San Francisco, CA, 2Loyola University Medical Center, Maywood, IL, 3Cedars-Sinai Medical Center, Los Angeles, CA, 4CareDx, Brisbane, CA, 5University of Southern California, Los Angeles, CA
Meeting: 2021 American Transplant Congress
Abstract number: 663
Keywords: Kidney transplantation, Monitoring, Non-invasive diagnosis, Retransplantation
Topic: Clinical Science » Biomarkers, Immune Assessment and Clinical Outcomes
Session Information
Session Name: Biomarkers, Immune Assessment and Clinical Outcomes
Session Type: Poster Abstract
Session Date & Time: None. Available on demand.
Location: Virtual
*Purpose: Repeat kidney transplants (RKT) represent 12.4% of kidney transplants (KT) (10.9% of all living donor and 13.6% of all deceased donor). Most RKT are performed >5 years following the primary kidney transplant (PKT). Inferior RKT outcomes are identified among patients having experienced graft loss after less than 5 years and are also considered higher immunological risk. Donor‐derived cell‐free DNA (dd‐cfDNA) has established utility in diagnosing the probability of active rejection in PKTs, however utility in RKTs published in two small series – Mehta, et al. (N=12 RKT) from the Diagnosing Acute Rejection in Kidney Transplant Recipients (DART study; ClinicalTrials.gov Identifier: NCT02424227) that demonstrated higher dd-cfDNA baseline than PKT; and Sureshkumar, et al. (N=12 RKT) whereupon no statistical difference in baseline was reported.
*Methods: 753 patients with PKT were compared with 260 RKT recipients, all having surveillance with dd-cfDNA (AlloSure®; CareDx) as part of the KOAR study. The lowest – referred to as baseline – dd-cfDNA levels within the first year of transplant were examined. The cohort included patients from both surveillance and clinical for cause testing as well as biopsy schedules.
*Results: The median baseline AlloSure dd-cfDNA for PKT was 0.20% (mean: 0.27%, variance:0.05), for RKT median was 0.19% (mean:0.35%, variance:0.24) with no significant difference (p = 0.66 with balanced sampling between groups) [FIGURE 1]. For the subset of patients who had an allograft rejection – PKT (n=80) and RKT (n=14) – a shift was observed in the mean baseline levels. For PKT and RKT it was 0.34% (variance:0.18) and 0.72% (variance:1.19), respectively (p = 0.35). In this cohort, elevated dd-cfDNA levels were observed at the time of the event. A median of 0.5% (mean: 1.06%, variance:3.05) was observed in PKT compared to median of 0.8% (mean:1.47%, variance:2.58) in RKT [FIGURE 2]. The observed differential trend was not statistically significant (p=0.503).
*Conclusions: RKT have equivalent baseline and dd-cfDNA elevations during allograft injury and rejection events as those observed with PKT. The similar performance characteristics of dd-cfDNA in RKT should support utility of this surveillance tool in the repeat kidney transplant population.
To cite this abstract in AMA style:
Peddi VR, Akkina S, Jordan SC, Tian W, Qazi Y. Donor-Derived Cell-Free DNA Performance Characteristics are Similar for Repeat and Primary Kidney Transplant Recipients [abstract]. Am J Transplant. 2021; 21 (suppl 3). https://atcmeetingabstracts.com/abstract/donor-derived-cell-free-dna-performance-characteristics-are-similar-for-repeat-and-primary-kidney-transplant-recipients/. Accessed May 11, 2025.« Back to 2021 American Transplant Congress