El Fekih Rania, Franzen Kurt, Hurley James, Haynes Brian C, Merhej Tamara, Alghamdi Areej, Hallmark Elliot, Xing Shuran, Kumar Sonia, Choi John, Solhjou Zhabiz, Deban Christa, Saad Anis, Halawi Ahmad, Younis Nour, Cashman Katherine, Dagher Maribel, Eskandari Siawosh K, Al Chaar Soltan, Rennke Helmut, Weins Astrid, Abdi Reza, Chandraker Anil, Markmann James F, Safa Kassem, Riella Leonardo V, McFaul Matt, Ventura Chris, Vlassov Alexandre V, Formica Richard, Macedo Camila, Skog Johan, Azzi Jamil R
Renal Division, Transplantation Research Center, Brigham and Women's Hospital and Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Exosome Diagnostics, a Bio-Techne brand, Waltham, Massachusetts, USA.
Kidney Int Rep. 2025 Feb 3;10(4):1131-1142. doi: 10.1016/j.ekir.2025.01.036. eCollection 2025 Apr.
We recently discovered 2 urinary exosomal mRNA signatures to identify and differentiate T-cell-mediated rejection (TCMR) from antibody-mediated rejection (ABMR) in kidney transplant recipients. Here, we developed Exosome Transplant Rejection Urine (ExoTRU), a urinetest based on a 4-gene signature from the previous discovery cohort, showed its clinical utility in a new cohort of kidney transplant recipients undergoing clinically indicated biopsies, and validated it through a separate laboratory in an independent-cohort of patients.
A workflow suited for clinical laboratories was developed, allowing for smaller urine volumes and widely standardized qPCR instrumentation. A total of 226 urine samples from 214 patients were paired with clinically indicated biopsies. Urinary exosomal mRNAs levels were evaluated for previously defined targets.
Four mRNAs (IL32, B2M, CXCL11, and PGK1) performed well in distinguishing biopsies with rejection or significant inflammation from those without inflammation, achieving 94% sensitivity, 62% positive predictive value, and 52% specificity. Patients who tested positive by the signature but negative by biopsy were nearly twice as likely to experience adverse outcomes in the 5-year follow-up period, including subsequent rejection, thereby showing the limitations of kidney biopsies and the prognostic potential of molecular signatures. The evaluation of an independent validation cohort showed similar performance, achieving an area under the curve (AUC) of 0.838. Another 6-gene signature distinguished TCMR from ABMR, with an AUC of 0.756.
Exosomal mRNA gene signatures identified patients with different stages and classes of rejection, including early stage and significant inflammation, enabling improved decision-making and patient management and reducing unnecessary biopsies by 45%. This represents a potential tool for risk stratification based on poor outcomes in patients with positive signatures.
我们最近发现了2种尿液外泌体mRNA特征，用于识别和区分肾移植受者中T细胞介导的排斥反应（TCMR）和抗体介导的排斥反应（ABMR）。在此，我们开发了外泌体移植排斥尿液检测法（ExoTRU），这是一种基于先前发现队列中的4基因特征的尿液检测方法，在一组接受临床指征活检的新的肾移植受者队列中展示了其临床实用性，并通过另一个实验室在独立患者队列中对其进行了验证。
开发了一种适用于临床实验室的工作流程，允许使用更少的尿量和广泛标准化的qPCR仪器。来自214名患者的总共226份尿液样本与临床指征活检进行配对。评估尿液外泌体mRNA水平的先前定义靶点。
四种mRNA（IL32、B2M、CXCL11和PGK1）在区分有排斥反应或显著炎症的活检与无炎症的活检方面表现良好，敏感性达到94%，阳性预测值为62%，特异性为52%。通过该特征检测呈阳性但活检呈阴性的患者在5年随访期内经历不良结局（包括随后的排斥反应）的可能性几乎是其他人的两倍，从而显示了肾活检的局限性以及分子特征的预后潜力。对一个独立验证队列的评估显示了类似的性能，曲线下面积（AUC）为0.838。另一个6基因特征区分了TCMR和ABMR，AUC为0.756。
外泌体mRNA基因特征可识别不同阶段和类型排斥反应的患者，包括早期和显著炎症，有助于改善决策和患者管理，并将不必要的活检减少45%。这代表了一种基于特征阳性患者不良结局进行风险分层的潜在工具。
