Exploring urinary extracellular vesicles for organ transplant monitoring: A comprehensive study for detection of allograft dysfunction using immune-specific markers

Background: Allograft dysfunction (AGD) is a common complication following solid organ transplantation (SOT). This study leverages the potential of urinary extracellular vesicles (UEVs) for the non-invasive detection of AGD. Aim: We aimed to assess the diagnostic value of T-cell and B-cell markers characteristic of T-cell-mediated and antibody-mediated rejection in UEV-mRNA using renal transplantation as a model. Materials and methods: UEVs were isolated from 123 participants, spanning healthy controls, functional transplant recipients, and biopsy-proven AGD patients. T-cell and B-cell marker mRNA expressions were evaluated using RT-qPCR. Results: We observed significant differences in marker expression between healthy controls and AGD patients. ROC analysis revealed an AUC of 0.80 for T-cell markers, 0.98 for B-cell markers, and 0.94 for combined markers. T-cell markers achieved 81.3 % sensitivity, 80 % specificity, and 80.4 % efficiency. A triad of T-cell markers (PRF1, OX40, and CD3e) increased sensitivity to 87.5 % and efficiency to 82.1 %. B-cell markers (CD20, CXCL3, CD46, and CF3) delivered 100 % sensitivity and 97.5 % specificity. The combined gene signature of T-cell and Bcell markers offered 93.8 % sensitivity and 95 % specificity. Conclusion: Our findings underscore the diagnostic potential of UEV-derived mRNA markers for T-cells and Bcells in AGD, suggesting a promising non-invasive strategy for monitoring graft health.