Background: Protocol renal allograft biopsy (P-Bx), capable of accurately assessing the status of the transplant kidney, is deemed crucial for potentially improving graft survival rates. However, there remains a lack of clear evidence supporting this notion, with numerous challenges to consider such as the intervals for performing transplant biopsies and the management of subclinical findings.
Purpose: The study investigated the impact of adherence to transplant kidney biopsies on graft survival rates and the progression of subclinical findings.
Objective and method: We investigated the effect of P-Bx (3 months, 1 year, and 3 years after transplantation) on graft survival in 268 patients who underwent living donor renal transplantation at Osaka University between January 2012 and March 2021. Subclinical T cell mediated rejection was treated with steroid pulses, while no active treatment was administered for subclinical antibody mediated rejection (sAMR).
Results: The graft survival of patients who underwent P-Bx at both 3 months and 1 year was not significantly different from those of the other patients in terms of death-censored graft survival but was prolonged considerably in terms of uncensored graft survival (p = 0.0459). Each did not reach the median value. There was no significant difference in survival rate based on subclinical rejection findings or a third-year biopsy. Among 61 cases of ABO-incompatible transplant patients who underwent a protocol biopsy at the third month, sAMR findings were observed in 8 cases, but in all cases, subsequent protocol biopsies showed the disappearance of sAMR findings. There was no significant difference in graft survival rates based on the presence or absence of sAMR. Conclusions: Adherence to P-Bx may potentially improve graft survival rates. sAMR in ABO-incompatible patients does not impact graft survival rates even without treatment.