Surveillance Biopsies in Pediatric Kidney Transplant Recipients

Abstract

Acute rejection is a significant risk factor for allograft loss in pediatric renal transplant recipients. Identifying and treating rejection prior to a clinical appearance by surveillance biopsy has been associated with improved allograft function and survival. There are no strong patient demographic patterns associated with increased risk of subclinical rejection. Appropriate surveillance biopsy time intervals have yet to be standardized to minimize risk and maximize clinical outcomes. We reviewed all renal allograft surveillance biopsies at six-, twelve-, and twenty-four-month intervals from February 2020 through September of 2022 at a tertiary care facility. Clinical history, relevant laboratory findings, immunosuppression and hypertension medications, and biopsy related complications were recorded. Subclinical rejection was identified in accordance with the Banff Diagnostic Categories of Renal Allograft Pathology. Descriptive statistical analysis was performed to identify clinical risk factors. Twenty-nine patients received a total of 47 surveillance biopsies. The mean age at date of transplant for the 29 subjects was 12.2 years (SD  5.0 years) and 18 (62%) were male. Subclinical inflammation or rejection was identified in three of 22 (13.6%) six-month surveillance biopsies, seven of 18 (38.9%) twelve-month surveillance biopsies, and none of the twenty-four-month surveillance biopsies. We experienced six (12.8%) minor complications (significant hematoma n=2; gross hematuria n=4). Our rates of rejection at each interval suggest a nine-month interval could be explored as an alternative for surveillance biopsies done at six- and twelve-months post-transplant. Twenty-four-month biopsies could be eliminated from the program due to a lack of positive findings.