PURPOSE: Standard laboratory measures are not sensitive indicators of kidney dysfunction following transplantation and may be less reliable in paediatric recipients. Early graft surveillance may extend survival. Protocol biopsies performed at predefined times following transplant can detect early subclinical rejection (SCR) and/or identify patients at risk for chronic changes. SCR can be treated by increased immunosuppression which may improve long-term outcomes.

METHODS: Retrospective review of a single-centre cohort of paediatric kidney transplant recipients (pKTR) who underwent protocol biopsies. At our centre, protocol biopsies are planned at 3, 6, and 12 months post-transplant. pKTR were included if they underwent a minimum of 1 protocol biopsy. Outcomes included: incidence and timing of SCR and borderline SCR (Banff criteria), biopsy complications and allograft loss. eGFR (estimated glomerular filtration rate; modified Schwartz equation) was calculated at 12 and 24 months post-transplant.

RESULTS: 47 ABO compatible pKTR (26 males, 23 LRD) transplanted between January 2000-August 2017 were included; mean age at transplant was 11.9 ±5 yrs. All patients received induction therapy. Immunosuppression consisted of tacrolimus or sirolimus, mycophenolate and prednisone. 124 protocol biopsies were included and analyzed. 89% of patients underwent ≥2 protocol biopsies. During the first year post-transplant SCR was found in 10% and borderline in 16% of all protocol biopsies (Table 1). There were no episodes of antibody-mediated rejection. No allografts were lost during follow-up.

Table 1 Incidence of SCR or Borderline SCR in Protocol Biopsies at 3, 6 & 12 months Post-Transplant

eGFR at 12 and 24 months was 87 ±22 ml/min/1.73m² and 82 ±28 ml/min/1.73m² respectively. Biopsy related complications included transient gross hematuria in 6% of biopsies and perirenal hematoma in 2% of biopsies.

CONCLUSION: Our study demonstrates the utility and relative safety of protocol biopsy monitoring during the first year post-transplant in a cohort of paediatric kidney transplant recipients. Early detection of SCR in the renal allograft provides information that would otherwise be missed allowing for early intervention.

CITATION INFORMATION: Alsulaimi T., Aloufi M., Grisaru S., Samuel S., Hamiwka L. Protocol Biopsies after Paediatric Kidney Transplantation: A Single Centres' 17 Year Experience Am J Transplant. 2017;17 (suppl 3).

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