HLA-DP antibodies before and after renal transplantation.

E.V. Billen, M.H. Christiaans, I.I. Doxiadis, C.E.M. Voorter, E.M. van den Berg-Loonen

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Abstract

Human leukocyte antigen (HLA)-DP is considered a target for humoral immune response in clinical transplantation. This study analyses the incidence of HLA-DP antibodies in renal patients. Development and epitope specificity of donor-specific antibodies (DSA) and non-DSA (NDSA) were examined. Pre- and posttransplant sera of 338 patients were screened for HLA-DP antibodies using the luminex single antigen assay. Positive patients, partners and/or kidney donors were HLA-DP typed by sequence-specific oligonucleotides. Potential epitopes were mapped by comparing the amino acid sequences of HLA-DP hypervariable regions (HVR) A-F of recipient, partner and/or donor. Specificities in the sera were aligned to deduce the HVR motif responsible for the antibodies. HLA-DP antibodies were detected in 14% of the patients (48/338). Before transplantation, the antibodies were shown in 23% (10 females and 1 male) and 77% were found after transplantation (30 in patients after the first, 7 after the second graft). Specificities were never restricted to individual mismatched antigens; broad HLA-DP sensitization was found as a rule. A single HVR mismatch was present in 80% of the DSA and in 79% of the NDSA. No HLA-DPA specific antibodies were found. Our findings confirm that HLA-DP antibodies are specific for epitopes shared by different HLA-DP antigens, indicating that only a restricted number of mismatched epitopes are recognized by the recipients immune system. Matching for immunogenic HLA-DP epitopes for renal transplantation seems to be functionally more relevant than classical matching at the allelic level.
Original languageEnglish
Pages (from-to)278-285
Number of pages8
JournalTissue Antigens
Volume75
Issue number3
DOIs
Publication statusPublished - 1 Jan 2010

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