Evaluation of the Modified Oxford Score in Recurrent IgA Nephropathy in North American Kidney Transplant Recipients: The Banff Recurrent Glomerulonephritis Working Group Report

Background. The modified Oxford classification mesangial and endocapillary hypercellularity, segmental sclerosis, interstitial fibrosis/tubular atrophy, and the presence of crescents (MEST-C) of immunoglobulin A nephropathy (IgAN) was recently shown to be a predictor of graft failure in Asians with recurrent IgAN. We aimed to validate these findings in a cohort from North American centers participating in the Banff Recurrent Glomerulopathies Working Group. Methods. We examined 171 transplant recipients with end-stage kidney disease because of IgAN; 100 of them with biopsy-proven recurrent IgAN (57 of them had complete MEST-C scores) and 71 with no recurrence. Results. IgAN recurrence, which was associated with younger age at transplantation (P = 0.012), strongly increased the risk of death-censored graft failure (adjusted hazard ratio, 5.10 [95% confidence interval (CI), 2.26-11.51]; P < 0.001). Higher MEST-C score sum was associated with death-censored graft failure (adjusted hazard ratio, 8.57 [95% CI, 1.23-59.85; P = 0.03] and 61.32 [95% CI, 4.82-779.89; P = 0.002] for score sums 2-3 and 4-5 versus 0, respectively), and so were the single components endocapillary hypercellularity, interstitial fibrosis/tubular atrophy, and crescents (P < 0.05 each). Overall, most of the pooled adjusted hazard ratio estimates associated with each MEST-C component were consistent with those from the Asian cohort (heterogeneity I2close to 0%, and P > 0.05). Conclusions. Our findings may validate the prognostic usefulness of the Oxford classification for recurrent IgAN and support the inclusion of the MEST-C score in allograft biopsies diagnostic reports.