Impact of preformed and de novo anti-HLA DP antibodies in renal allograft survival

• The influence of HLA DP antibodies detected by Luminex® on short and long-term graft survival is not well-known.
• 10% of kidney transplant recipients show anti-HLA DP antibodies in single antigen studies, both pre- and posttransplantation.
• The presence of DSA is associated with a negative impact on graft survival. However, the presence of HLA DP antibodies does not modify this impact.
• In selected cases of humoral rejection with undetected HLA A, B, DR or DQ DSA, HLA DP antibodies, as well as other non-HLA antibodies, should be assessed.
• Larger studies with kidney transplant donors well typed for HLA DP are needed to confirm our results.

The influence of antibodies against HLA-DP antigens detected with solid-phase assays on graft survival after kidney transplantation (KT) is uncertain. We evaluated with Luminex® the prevalence of pre- and posttransplant DP antibodies in 440 KT patients and their impact on graft survival. For 291 patients with available pretransplant samples, DP antibodies were present in 39.7% KT with pretransplant HLA antibodies and 47.7% with DSA. Graft survival of KT with pretransplant class-II DSA was worse than with non-DSA (p = 0.01). DP antibodies did not influence graft survival. Of 346 patients monitored post-KT, 17.1% had HLA class-II antibodies, 56% with DP antibodies. Class-II DSA was detected in 39%, 60.9% of them had DP antibodies. Graft survival was worse in patients with class-II DSA (p = 0.022). DP antibodies did not change these results. The presence of isolated DP antibodies was a rare event both pre- and posttransplantation (1.03 and 0.86%). The presence of pretransplant and posttransplant DSA is associated with a negative impact on graft survival. However, the presence of DP antibodies does not modify this impact significantly.