Outcomes of paediatric kidney transplant recipients using the updated 2013/2017 Banff histopathological classification for antibody-mediated rejection

Background: After the major changes with regard to acute and chronic ABMR in the Banff classification initiated in 2013, there has been an improvement in diagnosing antibody-mediated rejection (ABMR) in adult studies but no data have been published in the paediatric population. Methods: We assessed 56 paediatric kidney transplant biopsies due to kidney dysfunction in patients with donor-specific antibodies (DSA) in a retrospective single-centre study between January 2006 and March 2012. The results were compared with 2003/2007 Banff classification noting the subsequent 2017 and 2019 modifications do not change the 2013 Banff classification with regard to acute antibody-mediated rejection (apart from the addition of gene transcripts/classifiers that do not affect our analysis). Results: Following the 2013 Banff classification, there were seven cases (12.5%) diagnosed with ABMR that would have been misclassified when applying the 2003/2007 classification. Evaluating the histological features of all ABMR-related cases, we report the importance of v− (intimal arteritis) and t− (tubulitis) lesions: absence of v− and t− lesions in the biopsy is related to significantly higher kidney allograft survival (OR 7.3, 95%CI 1.1–48.8, p = 0.03 and OR 5.3, 95%CI 1.2–25.5, p = 0.04 respectively). Moreover, absence of t− lesions was associated with significantly fewer rejection episodes the year after the initial biopsy (OR 5.1, 95%CI 1.4–19.8, p = 0.01). Conclusions: Our study supports that the updated 2013 Banff classification shows superior clinicopathological correlation in identifying ABMR in paediatric kidney transplant recipients. Our results can be extrapolated to the recently updated 2019 Banff classification.