Relationship between autophagy and acute rejection after kidney transplant

Abstract

Objective: Acute rejection after kidney transplant is a complicated clinical problem. Autophagy is the intracellular lysosomal degradation and recycling of proteins and organelles, and is reported to be involved in various diseases. Microtubule-associated protein light chain 3 (LC3) is a widely used marker to monitor autophagic activity. The involvement of autophagy in acute rejection after kidney transplantation remains unknown. This prospective study aimed to investigate the utility of urinary LC3 to predict acute rejection after kidney transplant. Methods: The study included 28 patients who underwent kidney transplantation between 2014 and 2016. All patients gave informed consent. Patients were divided in 2 groups, according to the biopsy diagnosis at 3 months after kidney transplantation. Three patients showed biopsy-proven T cell-mediated rejection (TCMR group), and 25 patients showed no signs of rejection (Control group). Urine samples were collected at 7, 28, 56, and 84 days after transplantation. Urinary LC3 was measured using an enzyme-linked immunosorbent assay (ELISA) kit. The present study was approved by the Kyushu University Hospital ethics committee. Results: Compared to the Control group, the TCMR group showed no significant renal dysfunction as measured by serum Cr and eGFR before kidney transplantation. There was no significant difference in the urinary LC3 concentration at 7 and 28 days, between the two groups. However, the urinary LC3 concentration in the TCMR group was twofold higher compared to that in the Control group at 56 and 84 days post transplantation (P < 0.05). Conclusion: Our small study suggests that urinary LC3 may be used as a novel biomarker of acute rejection in kidney transplant recipients.