Initial results of our Luminex ABO-Ab assay are promising for clinical laboratory use, where bead-based assays are already used for HLA-Ab. The specificity of this assay will allow precise assessment of ABO-Ab to antigen subtypes, known to be expressed differently in cardiac endothelium than erythrocytes (1). The ability to measure IgM and IgG ABO-Ab makes it possible to evaluate of the role of each in potential graft damage; isotype differentiation may be particularly relevant in the setting of plasmapheresis, which more efficiently removes IgM than IgG antibodies. 1. Jeyakanthan, M et al. AJT 2016; 16: 1548-1558.

Organ transplantation from ABO blood group–incompatible (ABOi) donors requires accurate detection, effective removal and subsequent surveillance of antidonor antibodies. Because ABH antigen subtypes are expressed differently in various cells and organs, measurement of antibodies specific for the antigen subtypes in the graft is essential. Erythrocyte agglutination, the century‐old assay used clinically, does not discriminate subtype‐specific ABO antibodies and provides limited information on antibody isotypes. We designed and created an ABO‐glycan microarray and demonstrated the precise assessment of both the presence and, importantly, the absence of donor‐specific antibodies in an international study of pediatric heart transplant patients. Specific IgM, IgG, and IgA isotype antibodies to nonself ABH subtypes were detected in control participants and recipients of ABO‐compatible transplants. Conversely, in children who received ABOi transplants, antibodies specific for A subtype II and/or B subtype II antigens—the only ABH antigen subtypes expressed in heart tissue—were absent, demonstrating the fine specificity of B cell tolerance to donor/graft blood group antigens. In contrast to the hemagglutination assay, the ABO‐glycan microarray allows detailed characterization of donor‐specific antibodies necessary for effective transplant management, representing a major step forward in precise ABO antibody detection.

Jeyakanthan, M; Podlosky, L; Senthilselvan, S; Maier, S; Larsen, I; Nahirniak, S; West, L Author Information