Anti-HLA DP antibodies have been associated with renal allograft rejection and/or positive crossmatches. While the reactivity of anti-HLA DP Beta antibody (DPΒ-Ab) is described, less is known about the prevalence and patterns of anti-HLA DP Alpha antibodies (DPΑ-Ab).
Methods. We identified 186 consecutive renal transplant candidates or recipients tested between 20072012 for DPΑ- or DPΒ-Ab. The HLA-DP typing was performed by rSSO or SSP. Strong reactive/high-level antibodies were considered > 8000 mean fluorescence intensity (MFI) on Luminex single-antigen beads.
Results. One patient (0.5%) had DPΑ-Ab only, 139 (75%) had DPΒ-Ab only, and 46 (25%) exhibited both DPΑ- and DPΒ-Ab. The epitope distribution of DPΒ-Ab is summarized in table 1. Sixty-seven patients developed antibodies against a single DPΒ epitope, 67 towards two DPΒ epitopes, and 26 patients against more than two DPΒ epitopes.
|HLA-DPΒ Epitope Specificity (amino acid motifs)||56A, 85-87 EAV||56E, 85-87 GPM||56E, 85-87 EAV||56A, 85-87 GPM||84-87 GGPM||Other|
|# Patients with anti-HLA DPΒ Antibody||77||59||106||21||22||25|
|# Patients with high level anti-HLA DPΒ Antibody (>8000 MFI)||38 (49%)||24 (41%)||57 (54%)||8 (38%)||15 (68%)||0 (0%)|
High-level antibodies were detected in 72 cases (39%) and were associated with DPΑ reactivity: 77% (36/47) of cases with DPΑ-Ab + DPΒ-Ab were strong, versus only 25% (36/139) cases with DPΒ-Ab, p<0.0001. Furthermore, antibodies towards Α alleles DPA1*01:xx were associated with 84-87GGPM Β epitope, while antibodies towards Α alleles DPA1*02:xx were more prevalent in cases with 85-87EAV Β epitope (table 2).
|Antibody Specificity||High level Antibody (MFI>8000)||Low level Antibody (MFI<8000)||p =||with anti-84-87GGPM epitope antibody (N=22)||with anti-85-87EAV epitope antibody (N=53)||p<|
|HLA-DPA1*01:xx (N=19)||12 (63%)||7 (26%)||0.01||19 (86%)||0 (0%)||0.00001|
|HLA-DPA1*02:xx (N=26)||24 (92%)||2 (8%)||0.01||0 (0%)||26 (49%)||0.00001|
Conclusions. One quarter of renal transplant candidates/recipients with anti-HLA DP alloantibody have shown reactivity towards the Α chain. Antibodies against Α alleles HLA-DPA*01:xx were associated with antibodies towards Β-84-87GGPM epitope, while antibodies against Α alleles HLA-DPA*02:xx correlated with antibodies towards Β 85-87EAV epitope. Furthermore, the presence of HLA-DPΑ reactivity was associated with high level of alloantibodies.
To cite this abstract in AMA style:Girnita A, Brailey P, Portwood E, Cardi M, Govil A, Mogilishetty G, Alloway R, Woodle E. Anti-HLA DP Alpha Alloantibodies Are Associated with High Antibody Levels and Correlate with Individual HLA-DP Beta Epitopes in Renal Transplant Candidates and Recipients [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/anti-hla-dp-alpha-alloantibodies-are-associated-with-high-antibody-levels-and-correlate-with-individual-hla-dp-beta-epitopes-in-renal-transplant-candidates-and-recipients/. Accessed October 27, 2020.
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