Immune Cell Infiltrate in Chronic-Active Antibody-Mediated Rejection

Little is known about immune cell infiltrate type in the kidney allograft of patients with chronic-active antibody-mediated rejection (c-aABMR). In this study, multiplex immunofluorescent staining was performed on 20 cases of biopsy-proven c-aABMR. T-cell subsets (CD3, CD8, Foxp3, and granzyme B), macrophages (CD68 and CD163), B cells (CD20), and natural killer cells (CD57) were identified and counted in the glomeruli (cells/glomerulus) and the tubulointerstitial (TI) compartment [cells/high-power field (HPF)]. In the glomerulus, T cells and macrophages were the dominant cell types with a mean of 5.5 CD3 cells/glomerulus and 4 CD68 cells/glomerulus. The majority of T cells was CD8 (62%), and most macrophages were CD68 CD163 (68%). The TI compartment showed a mean of 116 CD3 cells/HPF, of which 54% were CD8 . Macrophage count was 21.5 cells/HPF with 39% CD68 CD163 . CD20 cells were sporadically present in glomeruli, whereas B-cell aggregates in the TI compartment were frequently observed. Natural killer cells were rarely identified. Remarkably, increased numbers of CD3 FoxP3 cells in the TI compartment were associated with decreased graft survival ( = 0.004). Renal allograft biopsies showing c-aABMR show a predominance of infiltrating CD8 T cells, and increased numbers of interstitial FoxP3 T cells are associated with inferior allograft survival.