Racial Differences in the Predictability of Donor-Derived Cell-Free DNA Among Renal Transplant Recipients
1Rush University Medical Center, Chicago, IL, 2CareDx, Brisbane, CA
Meeting: 2022 American Transplant Congress
Abstract number: 1674
Topic: Clinical Science » Kidney » 34 - Kidney: Acute Cellular Rejection
Session Information
Session Name: Kidney: Acute Cellular Rejection
Session Type: Poster Abstract
Date: Tuesday, June 7, 2022
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: Donor-Derived Cell-Free DNA (dd-cfDNA) is used to monitor for allograft rejection following renal transplantation. Baseline dd-cfDNA is higher in African American (AA) patients compared to non-African American (non-AA). We aimed to identify differences in dd-cfDNA between these two groups during rejection events.
*Methods: This is a single center retrospective cohort study. All renal transplant recipients who underwent allograft biopsy between 2018-2020 were included. Rejection was defined as any form of rejection: acute cellular (ACR), antibody mediated (AMR), or mixed using Banff classification. Dd-cfDNA measured at the time of allograft biopsy was used to determine area under the curve-receiver operating characteristic (AUC-ROC) performance of dd-cfDNA.
*Results: 40 patients [19 AA, 21 non-AA (14 Hispanic, 7 white)] were included with a total of 55 biopsies (27 AA, 28 non-AA). There were 28 rejection events (15 AA, 13 non-AA) and 27 non-rejection (12 AA, 15 non-AA). Median dd-cfDNA at rejection was 1.45% (IQR 0.53% to 2.5%) across the entire cohort. Among non-AA patients with rejection (7 AMR, 5 ACR, 1 mixed), median was 2.3% (IQR 0.89% to 4.4%). Among AA patients with rejection (9 AMR, 5 ACR, 1 mixed), median was 1.30% (IQR 0.38% to 1.8%). AA patients who did not have rejection had a median 0.2% (IQR 0.15% to 0.67%). Among all patients who did not have rejection, median dd-cfDNA was 0.24% (IQR 0.15% to 0.47%). AUC among all patients was 0.84 (95%CI = 0.74 to 0.95). AUC was 0.74 (95%CI 0.54 to 0.95) among AA patients versus 0.95 (95%CI = 0.88 to 1.00) in non-AA patients. Notably, 33% of AA patients (n=5; 3 ACR, 1 AMR, 1 mixed) experienced rejection with dd-cfDNA less than 0.5%, compared to 0.08% of non-AA patients (n=1, AMR).
*Conclusions: Previous studies have shown that AA patients have higher baseline dd-cfDNA levels compared with non-AA patients. However, our study demonstrates that rejection among AA patients is associated with lower dd-cfDNA values compared to non-AA patients; maybe the relative change value (RCV) or trend is more useful in this group. Further investigation should be pursued to better understand this discrepancy.
To cite this abstract in AMA style:
Williams MD, Nimmagadda N, Patel S, Olaitan O. Racial Differences in the Predictability of Donor-Derived Cell-Free DNA Among Renal Transplant Recipients [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/racial-differences-in-the-predictability-of-donor-derived-cell-free-dna-among-renal-transplant-recipients/. Accessed May 17, 2025.« Back to 2022 American Transplant Congress