Incidences of preformed and de novo donor-specific HLA antibodies and their clinicohistological correlates in the early course of kidney transplantation.

Our center started routine monitoring of preformed and de novo human leukocyte antigen donor-specific antibodies (DSA) in September 2010 using single antigen beads on the Luminex platform. Recipients with preformed DSA or other high immunological risk factors had serial DSA monitoring at 3, 6, and 12-months posttransplant, and low-risk recipients were screened only at 12-months. Surveillance biopsies were performed at 3, 6, and 12-months post-transplant for all recipients. In addition, for-cause biopsies and DSA testing were performed when clinically indicated for allograft dysfunction. Among 150 adult kidney and kidney/pancreas transplant recipients included in the analysis, 14% had preformed DSA and 7.8% of recipients without preformed DSA developed de novo DSA by 12-months. De novo DSA developed in 25% of recipients on cyclosporine compared to 5% of those on tacrolimus (p = 0.02). The incidences of acute rejection were 34%, 48%, and 70% in recipients with no DSA, with preformed DSA, and with de novo DSA, respectively (p = 0.05). In all recipients with de novo DSA and rejection, the first rejection episode preceded or was concurrent with the emergence of de novo DSA. Despite the difference in rejection incidences, the estimated glomerular filtration rate at 1-year was not significantly different between recipients with or without DSA.