Introduction: In spite of publications reporting higher detection of subclinical rejection (SR) with protocol biopsies in kidney transplant (KT) recipients there is no recommendation with high grade evidence to generalize this surveillance strategy. The aim of this study was to describe the frequency of abnormalities on protocol biopsy at third month post-KT and evaluate their impact on several outcomes.

Methods: In a prospective cohort, all consecutive patients who underwent KT at our institution and had protocol third month post-RT biopsy from January 2013 to December 2015 were included.

Results: A total of 158 patients were included with the following characteristics: 51% were male, median age was 32 years (18-72), the cause of chronic kidney disease was unknown 44%, diabetic nephropathy 15%; 49% were from deceased donors. The frequency of findings on the 3-months protocol biopsies were: 53% normal, 24% borderline changes, 10% humoral rejection, 3% cellular rejection, 2% recurrent glomerulonephritis or de novo, and 8% other findings. Regarding recipients IR, the presences of donor specific antibodies (DSAs) pre-KT (p<0.05) and re-transplant recipients (p<0.05) were associated with humoral rejection. The low risk biopsies, group A (normal and borderline changes biopsies), were associated with a smaller decrease on estimated glomerular filtration rate (eGFR) compared to high risk biopsies, group B (immunological and non immunological findings) delta eGFR 0 mL/min/1.73m² versus -10.3 mL/min/1.73m² (p<0.05). Regardless of the findings on the biopsies, no difference was observed on the appearance of de novo DSA on the 1-year post-KT. High risk biopsies showed a higher percentage of interstitial fibrosis and tubular atrophy (IFTA) in the 1-year protocol biopsy, compared to low risk biopsies, 25% versus 10%, (p=0.01).

Conclusions: Twenty-three percent of third month post-KT biopsies presented a finding, immunological or non-immunological, which was associated with a decrease of eGFR in the 1-year post-KT. SR is more frequent in patients with DSA pre-RT and recipients with re-transplant. High risk biopsies are associated with a greater percentage of IFTA in 1-year biopsy. Therefore, we consider that protocol third month post-KT biopsy is a useful strategy in surveillance and treatment of post-KT.

CITATION INFORMATION: Rosado-Canto R, Barrientos-Aguilar C, Parra-Avila I, Marino L, Arvizu-Hernandez M, Uribe-Uribe N, Morales-Buenrostro L. The Value of Protocol Biopsy at Third Month After Kidney Transplant: A Single-Center Cohort Analysis. Am J Transplant. 2017;17 (suppl 3).

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