Donor-derived Cell-free DNA in Infections in Kidney Transplant Recipients: Case Series

BACKGROUND. Donor-derived cell-free DNA (dd-cfDNA) is a noninvasive plasma biomarker to evaluate for transplant allograft rejection. The relationship between infectious complications in kidney allografts and dd-cfDNA has received cursory attention in prior publications. METHODS. Retrospective review of all renal transplant recipients who underwent dd-cfDNA testing between November 2017 and August 2019. RESULTS. We report on 7 cases in whom infections affecting the transplanted kidney were associated with elevation in dd-cfDNA without concomitant rejection or elevation in serum creatinine. Five patients had BK viremia, and 2 patients had urinary tract infection associated with elevated dd-cfDNA levels. CONCLUSIONS. These observations suggest that elevations in dd-cfDNA are not specific to kidney allograft rejection and can be associated with infections affecting the transplanted kidney. This biomarker may be valuable in evaluating infectious complications of kidney allografts.