ABO Hemagglutination Titres Do Not Accurately Reflect ABO Antibody Levels
1Pediatrics/Dept of Laboratory Medicine, University of Alberta/Alberta Precision Laboratories, Edmonton, AB, Canada, 2Pediatrics, University of Alberta, Edmonton, AB, Canada, 3Academia Sinica, Institute of Biological Chemistry, Taipei, Taiwan, 4Chemistry, University of Alberta, Edmonton, AB, Canada, 5Pediatrics, University of Alberta, Canadian Donation and Transplant Research Program, Edmonton, AB, Canada
Meeting: 2022 American Transplant Congress
Abstract number: 936
Keywords: Alloantibodies, Histocompatibility, Isoantibodies, Organ Selection/Allocation
Topic: Basic Science » Basic Science » 11 - Histocompatibility and Immunogenetics
Session Information
Session Name: Histocompatibility and Immunogenetics
Session Type: Poster Abstract
Date: Sunday, June 5, 2022
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: ABO antibody (ABO-Ab) quantification is essential for risk assessment for ABO-incompatible (ABOi) transplantation, but the hemagglutination assay (HA) for ABO-Ab titres is known to be plagued by poor reproducibility and variable sensitivity. Our aim was to quantify IgG and IgM ABO-Ab as Luminex mean fluorescence intensities (MFI) values and compare to HA titres.
*Methods: Healthy adult samples from all ABO groups (n=87; 60% female) were tested by “standard” HA (no AHG). Serially diluted sera (50uL) were incubated with 25uL of 1% A1 and B reagent red cells at room temperature; HA titre was reported as the last dilution showing visual agglutination. The same samples were tested against in-house developed Luminex ABO single antigen beads (ABO-A and -B subtype I-VI glycans were coupled to individual beads). ABO-Abs bound to the Luminex beads were detected with either anti-human IgG or IgM secondary antibodies.
*Results: Although a pattern of increasing median IgM MFI vs HA titres was evident (Fig 1a,1c), each titre reflected a wide range of IgG and IgM MFI (Fig 1b, 1d). No significant sex-based differences in titres or MFI were detected (not shown).
*Conclusions: These results suggest that HA titre alone is insufficient to accurately assess ABOi transplant risk. IgG antibodies can contribute to non-AHG HA titres and each ABO titre includes an unpredictable range of ABO-Abs. Tools such as this bead-based ABO assay will allow more accurate ABOi transplant risk assessment and inform the relative contribution of specific ABO-Ab isotypes.
To cite this abstract in AMA style:
Halpin A, Ellis T, Pearcey J, Motyka B, Lowary TL, Cairo C, Maier S, West LJ. ABO Hemagglutination Titres Do Not Accurately Reflect ABO Antibody Levels [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/abo-hemagglutination-titres-do-not-accurately-reflect-abo-antibody-levels/. Accessed December 3, 2024.« Back to 2022 American Transplant Congress