Acute Antibody-Mediated Rejection in Kidney Transplant Based on the 2013 Banff Criteria: Single-Center Experience in Uruguay

Abstract Background Acute antibody-mediated rejection (AMR) diagnosis criteria have changed in recent consensus of Banff, with current evidence of C4d-negative AMR. Our objective was to evaluate incidence of AMR in renal transplantation according to Banff 2013 criteria and to examine the histological features and outcome. Methods This retrospective study involved all kidney transplants with histological diagnosis of acute rejection (AR) at our center between 2000 and 2014. All the biopsies with AR were re-assessed by a nephro-pathologist and classified by use of the Banff 2013 criteria. Results Of 205 kidney transplants, biopsy-proven AR was diagnosed in 25 cases (12%). Re-assessing them according to Banff 2013 criteria, AMR was diagnosed in 17 (8.3%) and represented 68% of the confirmed rejections. AMR diagnosis was performed on day 23 ± 26, with median of 11 days. From the 17 cases, 7 had concomitant T-cell–mediated rejection. All cases presented endothelial edema and acute tubular necrosis. Glomerulitis was found in 12 cases and capillaritis in 14. In 3, associated thrombotic micro-angiopathy (TMA) was found. Intimal and transmural arteritis was evidenced in 5 and 1 patient. In 2, transplant glomerulopathy was present. Seven of the 10 biopsies with C4d staining in the peri-tubular capillaries were positive. Twelve cases received plasmapheresis, 6 received gamma-globulin, and 6 received rituximab. After administration of anti-AMR therapy, 16 cases recovered renal function, reaching a serum creatinine level of 1.5 ± 0.6 mg %. Graft survival at 1 year was lower in the AMR group versus patients without AMR (81.9% vs 98.9%, log-rank test, P < .001). Risk factors for AMR were re-transplant (30% vs 7%, P = .02), HLA-DR mismatch (1.06 ± 0.65 vs 0.7 ± 0.6, P = .03), panel-reactive antibody (28% ± 33 vs 6.2 ± 13, P = .00), and delayed graft function (82% vs 30%, P = .00). Conclusions Adapting the new Banff 2013 criteria increased the sensitivity of the diagnosis of ARM. Regarding our data, despite an adequate response to the therapy, it resulted in a worse graft survival by the first year of renal transplant.