Utility of protocol biopsy in the management of renal allograft recipients

Abstract

Background: Many studies suggest that early rejection episodes and chronic changes in the allograft kidneys were often subclinical without a concomitant rise in the serum creatinine or proteinuria. Early identification of subclinical pathology by doing protocol biopsy and appropriate intervention is likely to improve long-term graft outcomes. However, it is often not done, out of concern about the procedure-related complications. Methods: All patients who underwent live donor kidney transplantation at Aster Medcity from September 2019 to August 2021 with stable graft function were included in the study. Stable graft function is defined as variation in the creatinine values of <25% from the nadir creatinine. Protocol biopsies were taken at 3 months after transplant surgery. Biopsies were done using spring-loaded biopsy guns percutaneously under ultrasound guidance, and patients were observed for 24 h in the hospital for any complication. Biopsies were analyzed by light microscopy and C4d staining and scored based on the Banff classification 2017 update. Results: Seventy patients underwent protocol kidney biopsy at a prespecified time of 3 months. Majority of our patients (74.3%) received a kidney from the first-degree blood relatives, and the rest (25.7%) of the patients received kidneys from spouses. Induction therapy was given in 57% of the patients, and the rest (43%) were transplanted without an induction agent. Of 70 specimens studied, 44 (62.9%) had normal histology and 26 (37.1%) had varying degrees of histological abnormalities. Thirteen (18.6%) had evidence of subclinical rejection, of which 12 (17.2%) showed borderline rejection and 1 (1.4%) had acute T-cell-mediated rejection (acute TCMR). Other histological findings include chronic active TCMR in 1 (1.4%), varying degrees of interstitial fibrosis and tubular atrophy in 5 (7.1%), evidence of BK virus nephropathy in 2 (2.8%), features of tacrolimus toxicity in 2 (2.8%), and acute interstitial nephritis in one patient. None of the patients developed any complication after the procedure. With appropriate treatment interventions, all patients had stable graft functions at 6-month follow-up. Conclusions: Protocol graft biopsy under real-time ultrasound guidance has a very good safety profile and can help the clinician optimize the immunosuppression with more precision, and on a long term, it might prove cost effective to the patient.