Incidence and Impact of Anti-HLA-DP-Antibodies in Renal Transplantation.

Abstract

Background: The role of HLA-DP-antibodies in renal transplantation is still poorly defined, whereas the clinical importance of DQ-antigens is widely accepted. This study aims to describe the incidence of donor- and non-donor specific antibodies against HLA-DP antigens in patients with renal transplantation. Methods: In a cohort of 112 kidney transplant patients, 97 recipients and their donors were typed for DP antigens by high-resolution sequence-specific oligonucleotides. Sera taken pre-transplant and at 1,3,6,9,12 months and annually post-transplant were retrospectively tested for anti-HLA-DP-antibodies using LABScreen single antigen bead. Results: In 43 (44.3%) patients, anti-HLA-DP-antibodies were found. 67.4% (n=29) were present in the pre-transplant sample and 32.6% (14) were exclusively found post-transplant. The median time from transplantation to antibody detection in the serum was 16.3 months. 71.4% (26) of the antibodies had a mean fluorescence intensity (MFI) between 1000 and 2000. 28.6% (17) had a MFI greater than 2000. There was no difference in MFI-levels between preformed and de novo anti-DP-antibodies. 50% (7) of the de novo anti-DP-antibodies accompanied de novo donor-specific antibodies (DSA) against HLA Class I (1), Class II (3) or both (3). 14% (2) were donor-specific antibodies. The 36 months graft survival was significantly reduced with de novo anti-DP-antibodies (p=0.012) (Figure 1): 50% (3) of the patients losing the graft within 36 months post-transplant had non-donor-specific anti-DP-antibodies. In two patients these antibodies accompanied donor-specific anti-DR- and DQ-antibodies.Figure: No Caption available.Conclusions: Antibodies against HLA-DP antigens are common in a cohort of renal transplantation and might have a harmful effect on the graft.