Total Cell-Free DNA as a Noninvasive Biomarker of a Delayed Graft Function After Kidney Transplantation From Donors After Cardiac Death.

BACKGROUND: Because of the organ shortage, donation after cardiac death (DCD) kidney transplantation (KTx) is an alternative way of achieving KTx using brain-dead donors (BDs). Although the prognosis of DCD-KTx is improving, the graft suffers from delayed graft function (DGF), the management of which is essential. With progress in understanding the characteristics of cell-free DNA (CF-DNA), we consider plasma total CF-DNA (tCF-DNA) to be a useful biomarker for predicting DGF in DCD-KTx.

STUDY DESIGN AND METHOD: Consecutive patients from living donors (LDs; n = 9), BDs (n = 8), or DCD donors (n = 13) were enrolled. Plasma samples were collected after KTx and on postoperative days 3 and 5. CF-DNA was isolated, and tCF-DNA was quantified using the TapeStation 2200 software program.

RESULTS: The tCF-DNA levels after BD-KTx and DCD-KTx were higher than those after LD-KTx (LD, 78 ± 27 (ng/mL); BD, 99 ± 20; DCD, 150 ± 23); the difference between DCD-KTx and LD-KTx was statistically significant (P < .05). The tCF-DNA levels declined at postoperative day 5 (LD, 45 ± 10; BD, 51 ± 11; DCD, 66 ± 13). tCF-DNA levels were significantly increased in patients with DGF after KTx (DGF, 139 ± 22; immediate function, 91 ± 18; P < .05). The tCF-DNA level was correlated with the duration of DGF (r = 0.5825, P < .05).

CONCLUSION: Although the mechanism underlying DNA release from transplanted grafts into the recipient circulation remains unclear, cell death by apoptosis or necrosis and the active secretion of the immune system may play important roles in DGF. These data suggest that monitoring tCF-DNA may help predict graft recovery after DCD-KTx.