Do Pre or Postransplant Anti-DP Antibodies Impact Kidney Graft Survival?

Abstract

Solid-phase assays on Luminex platform employing beads with purified HLA antigens assess the presence of antibodies against classical HLA antigens A, B and DR, but also C, DQ or DP. DP antibodies have been considered less immunogenic than other class II antibodies. There is not much information about the frequency and impact on graft survival of DP antibodies in kidney transplantation (KT). We have evaluated the prevalence of DP antibodies in our cohort of transplant patients and the impact of DP antibodies in patients with and without donor-specific antibodies (DSA) Methods Prospective study of 440 KT recipients (performed 1979-2012 across negative CDC XM) recruited I/2008-III/2012. Pre and postransplant serum samples were tested with Luminex Lifecodes LifeScreen y LSA Class II (Gen-probe,Stanford,CT) kits. Raw-MFI values >1000 for any single antigen bead were considered positive. Results 291 KT patients had preTR samples tested: 68 (23.4%) had HLA class II antibodies, DSA in 36 cases (52.9%). DP antibodies were present in 27/68 (39.7%) patients with pretransplant HLA antibodies and in 17/36 (47.7%) with DSA. Death-censored graft survival of pretransplant DSA-II patients (median 76.5 months) was worse than HLA non-DSA patients (p=0.005). The presence of DP antibodies did not influence graft survival (with or without DSA)[Figure 1].346 KT patients were monitored after KT (median: 54 months): 59 (17.1%) had HLA class II antibodies and 33/59 (56%) with DP antibodies. Twenty-three patients had DSA-II (39%) and 14/23 (60.9%) with anti-DP. At 40 months, death-censored graft survival was worse in patients with DSA II (p=0,022). DP antibodies did not change these results.Figure: No Caption available.Conclusions DP antibodies are detected in around half KT recipients with pretransplant DSA and 61% after transplantation. Detection of DSA class II with single antigen beads before or after transplantation associates with worse graft-survival, but the presence of DP antibodies does not modify the impact.