Utilization of donor‐derived Cell‐Free DNA in pediatric kidney transplant recipients: A single center study

Abstract High donor‐derived cell‐free DNA (dd‐cfDNA) levels indicate transplant allograft injury and can identify graft rejection in kidney transplant recipients. Here, we evaluated the use of dd‐cfDNA in pediatric kidney transplant rejection monitoring and treatment. Methods Forty‐two pediatric kidney transplant patients were enrolled between February 2020 and August 2021. Dd‐cfDNA was tested before and after biopsy/rejection treatment. There was a total of 61 allograft biopsies (44 for‐cause, 17 surveillance). Results Graft rejection was found in 35/61 biopsies. Rejection was more common in basiliximab induction compared to rATG (77.1% vs. 22.9%, p = .0121). Median dd‐cfDNA was higher in those with rejection (1.2% [0.34–3.12] vs. 0.24% [0.08–0.78], p < .0001). Dd‐cfDNA was highest in biopsies with AMR and mixed AMR/TCMR. In addition, dd‐cfDNA in basiliximab induction was higher compared to rATG (0.92% [0.27–1.8] vs. 0.26% [0.08–2], p = .0437). Median change in dd‐cfDNA after rejection treatment was −0.57% (−1.67 to 0.05). Median time to dd‐cfDNA <1% post‐rejection treatment was 8.5 days (3.0–19.5). Dd‐cfDNA in AMR was higher compared to TCMR or mixed rejection, and levels remained higher in AMR after treatment. In surveillance biopsies, 4/17 had rejection. Median dd‐cfDNA was not different in those with versus without rejection (0.48% vs. 0.28%, p = .2342). Those without rejection all had dd‐cfDNA <1%. In those with rejection, only one patient had dd‐cfDNA >1%, and all had TCMR. Conclusions Our findings support dd‐cfDNA as a useful indicator of graft rejection and response to treatment. Additional studies are needed to determine the role of dd‐cfDNA in graft health surveillance.