High levels of dd‐cfDNA identify patients with TCMR 1A and borderline allograft rejection at elevated risk of graft injury

The clinical importance of subclinical, early T cell–mediated rejection (Banff TCMR 1A and borderline lesions) remains unclear, due, in part to the fact that histologic lesions used to characterize early TCMR can be nonspecific. Donor‐derived cell‐free DNA (dd‐cfDNA) is an important molecular marker of active graft injury. Over a study period from June 2017 to May 2019, we assessed clinical outcomes in 79 patients diagnosed with TCMR 1A/borderline rejection across 11 US centers with a simultaneous measurement of dd‐cfDNA. Forty‐two patients had elevated dd‐cfDNA (≥0.5%) and 37 patients had low levels (