Dynamics of anti‐human leukocyte antigen antibodies after renal transplantation and their impact on graft outcome

The purpose of this study was to sequentially monitor anti‐ HLA antibodies and correlate the results with antibody‐mediated rejection ( AMR ), graft survival ( GS ), and graft function ( GF ). We collected sera from 111 kidney transplant recipients on transplant days 0, 7, 14, 30, 60, 90, 180, and 360 and analyzed PRA levels by ELISA . DSA s were analyzed by single‐antigen beads in rejecting kidneys. At pre‐transplant, 79.3% of the patients were non‐sensitized ( PRA  = 0%) and 20.7% were sensitized ( PRA  > 1%). After transplant, patients were grouped by PRA profile: no anti‐ HLA antibodies pre‐ or post‐transplant (group HLA pre−/post−; n = 80); de novo anti‐ HLA antibodies post‐transplant (group HLA pre−/post+; n = 8); sensitized pre‐transplant/increased PRA post‐transplant (group HLA pre+/post↑; n = 9); and sensitized pre‐transplant/decreased PRA post‐transplant (group HLA pre+/post↓; n = 14). De novo anti‐ HLA antibodies were detected at 7–180 d. In sensitized patients, PRA levels changed within the first 30 d post‐transplant. Incidence of AMR was higher in HLA pre−/post+ and HLA pre+/post↑ than in HLA pre−/post−, and HLA pre+/post↓ (p < 0.001) groups. One‐yr death‐censored GS was 36% in group HLA pre+/post↑, compared with 98%, 88% and 100% in groups HLA pre−/post−, HLA pre−/post+, and HLA pre+/post↓, respectively (p < 0.001). Excluding first‐year graft losses, GF and GS were similar among the groups. In conclusion, post‐transplant antibody monitoring can identify recipients at higher risk of AMR .