Antibody-Mediated Acute Vascular Rejection of Kidney Allografts: Fifteen-Year Follow-up

Abstract

BackgroundAlthough acute vascular rejection (AVR) is associated with a high risk of graft loss, it remains unclear whether AVR with accompanied cellular or humoral rejection (AHR) has dissimilar outcomes. The aim of this study was to examine the association between subtypes of AVR and graft loss. MethodsWe assessed patients who provided biopsy samples for acute allograft rejection from 1998 to 2014. To investigate distinct rejection patterns, we retrospectively assessed rejection episodes with review of graft histology as well as donor-specific anti-HLA antibodies when available. ResultsA total of 1,004 patients were biopsied and included in the main analyses, of which 259 (32.87%) had acute biopsy-proven rejection. We identified three patterns of graft rejection defined according to the presence of peritubular capillaritis (ptc): a) T-cell–mediated acute vascular rejection if ptc free; b) humoral-mediated acute vascular rejection if ptc >0; and c) T-cell–mediated rejection if vasculitis = 0 and ptc = 0 (148 [57%], 70 [27%], and 41 [16%], respectively). At 5 years, graft survival was lower among patients with ptc-vascular rejection than those with T-cell vascular rejection (72.3% vs 83.2%; P = .010). T-cell–mediated rejection without vasculitis had similar survival compared with rejection absence (89.3% vs 8 9.2%; P = .698). Multivariate analysis adjusted by age and sex showed that risk of graft loss was higher in biopsies with high scores of glomerulitis (g2-g3); vasculitis (v2-v3), capillaritis (ptc2-ptc3), or interstitial inflammation (i2-i3). However, tubulitis and C4d were not statically significant. ConclusionsWe conclude that antibody-mediated AVR involves a poorer prognosis than T-cell–mediated AVR. The presence of tubulitis does not seem to determine a poor long-term renal graft prognosis.