%0 Journal Article %A Kiran K. Khush %A Iwijn De Vlaminck %A Helen Luikart %A David J. Ross %A Mark R. Nicolls %T Donor-derived, cell-free DNA levels by next-generation targeted sequencing are elevated in allograft rejection after lung transplantation %D 2021 %R 10.1183/23120541.00462-2020 %J ERJ Open Research %P 00462-2020 %V 7 %N 1 %X Surveillance after lung transplantation is critical to the detection of acute cellular rejection (ACR) and prevention of chronic lung allograft dysfunction (CLAD). Therefore, we measured donor-derived cell-free DNA (dd-cfDNA) implementing a clinical-grade, next-generation targeted sequencing assay in 107 plasma samples from 38 unique lung transplantation recipients with diagnostic cohorts classified as: (1) biopsy-confirmed or treated ACR, (2) antibody-mediated rejection (AMR), (3) obstructive CLAD, (4) allograft infection (INFXN) and (5) Stable healthy allografts (STABLE). Our principal findings are as follows: (1) dd-cfDNA level was elevated in ACR (median 0.91%; interquartile range (IQR): 0.39–2.07%), CLAD (2.06%; IQR: 0.57–3.67%) and an aggregated cohort of rejection encompassing allograft injury (1.06%; IQR: 0.38–2.51%), compared with the STABLE cohort (0.38%; IQR: 0.23–0.87%) (p=0.02); (2) dd-cfDNA level with AMR was elevated (1.34%; IQR: 0.34–2.40%) compared to STABLE, although it did not reach statistical significance (p=0.07) due to limitations in sample size; (3) there was no difference in dd-cfDNA for allograft INFXN (0.39%; IQR: 0.18–0.67%) versus STABLE, which may relate to differences in “tissue injury” with the spectrum of bronchial colonisation versus invasive infection; (4) there was no difference for dd-cfDNA in unilateral versus bilateral lung transplantation; (5) “optimal threshold” for dd-cfDNA for aggregated rejection events representing allograft injury was determined as 0.85%, with sensitivity=55.6%, specificity=75.8%, positive predictive value (PPV)=43.3% and negative predictive value (NPV)=83.6%. Measurement of plasma dd-cfDNA may be a clinically useful tool for the assessment of lung allograft health and surveillance for “tissue injury” with a spectrum of rejection.Donor-derived cell-free DNA monitoring in plasma can detect allograft rejection and quiescence after lung transplantation https://bit.ly/3cIQITT %U https://openres.ersjournals.com/content/erjor/7/1/00462-2020.full.pdf