Discrepant Antibody Testing Results: Which One to Believe?

The impact of solid-phase immunoassay for HLA antibody detection on the field of transplantation has been extremely significant by providing the most sensitive and precise method for characterization of HLA antibodies. However, despite all the benefits, technical limitations and inherent artifacts represent significant challenges, particularly with Luminex-based single-antigen bead (SAB) assay. Discordant results between antibody detection (screening assay) and identification (SAB) is not uncommon.

The dilemma of DQ HLA-antibodies.

Accurate identification of antibody reactivity against HLA-DQ antigens was difficult by using the old serological assays because of the strong linkage disequilibrium between HLA-DR and HLA-DQ (the usual inheritance of a certain HLA-DR molecule that ties together with the same DQ molecule within a racial group). The accurate and precise identifications of anti-HLA-antibodies of DQ specificities were made possible with the introduction of multiplex-bead arrays (Luminex), using single antigen bead (SAB) assay. The SAB assay is also considered today to be the most sensitive and specific method for alloimmunization assessment even for the low titer anti-HLA-antibodies.