Protocol Biopsies in Delayed Graft Function Kidney Transplants From Brain-Dead Donors

Delayed graft function (DGF) is a significant challenge in deceased donor kidney transplantation, impacting approximately one third of patients and is associated with acute rejection. Post-transplant acute rejection is monitored in kidneys with DGF through sequential protocol biopsies in 7-10-day intervals, according to guidelines based on research done before the current era of immunosuppression treatment. As acute rejection rates have decreased, there is a need to reevaluate the rationale of protocol biopsies.

We studied the histology of all biopsies taken during the first month post-transplant among recipients of brain-dead donor kidneys with DGF at our institution during 2006-2023. All recipients received corticosteroids as induction. Anti-thymocyte globulin was additionally administered to 3% and 18% receive basiliximab.

A total of 1022 biopsies were studied from 678 recipients. Of the 678 recipients, 178 (26%) had rejection. Most acute rejection episodes occurred 7-10 days post-transplant. In case of no rejection in the first biopsy, rejection was found in 10% of the cases with subsequent biopsies. No risk factors for acute rejection in these later biopsies could be identified in regression analysis. The presence of donor-specific human leukocyte antibodies was associated with higher rates of antibody-mediated rejection during the first post-transplant month (20% vs. 1.3%, p < 0.001).

The first biopsy post-transplant in DGF kidneys has an important role in identifying early acute rejection. Of the patients with no rejection in the first biopsy, only 10% had a rejection in the second biopsy. Cases with borderline findings progressed to rejection in approximately one third of the cases. These data reflect the rate of early TCMR in deceased donor kidney transplants when 79% of patients did not receive an anti-T cell induction antibody.