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 (<0.5%). Elevated levels of dd‐cfDNA predicted adverse clinical outcomes: among patients with elevated cfDNA, estimated glomerular filtration rate declined by 8.5% (interquartile rate [IQR] −16.22% to −1.39%) (−3.50 mL/min/1.73 m² IQR −8.00 to −1.00) vs 0% (−4.92%, 4.76%) in low dd‐cfDNA patients (P = .004), de novo donor‐specific antibody formation was seen in 40% (17/42) vs 2.7% (P < .0001), and future or persistent rejection occurred in 9 of 42 patients (21.4%) vs 0% (P = .003). The use of dd‐cfDNA may complement the Banff classification and to risk stratify patients with borderline/TCMR 1A identified on biopsy.

中文翻译：

---

高水平的 dd-cfDNA 可识别患有 TCMR 1A 和边缘同种异体移植排斥的患者，移植物损伤的风险较高。

亚临床早期 T 细胞介导的排斥反应（Banff TCMR 1A 和交界性病变）的临床重要性仍不清楚，部分原因是用于表征早期 TCMR 的组织学病变可能是非特异性的。供体来源的游离 DNA (dd-cfDNA) 是活动性移植物损伤的重要分子标志物。在 2017 年 6 月至 2019 年 5 月的研究期间，我们评估了美国 11 个中心的 79 名诊断为 TCMR 1A/边缘排斥的患者的临床结果，同时测量了 dd-cfDNA。42 名患者的 dd-cfDNA 升高（≥0.5%），37 名患者的 dd-cfDNA 水平较低（<0.5%）。dd-cfDNA 水平升高预示着不良的临床结果：在 cfDNA 升高的患者中，估计肾小球滤过率下降 8.5%（四分位数[IQR] -16.22% 至 -1.39%）(-3.50 mL/min/1.73 m 2 ^IQR ) -8.00 至 -1.00) vs 0% (-4.92%, 4.76%) 在低 dd-cfDNA 患者中 ( P  = .004)，从头形成供体特异性抗体的比例为 40% (17/42) vs 2.7% ( P  < .0001)，42 名患者中有 9 名 (21.4%) 与 0% ( P  = .003) 发生了未来或持续排斥反应。dd-cfDNA 的使用可以补充 Banff 分类，并对活检中确定的边缘/TCMR 1A 患者进行风险分层。