Simultaneous Use of Two Recombinant Blood Group Antigens for Identification of Rare Complex Antibody Mixtures

BACKGROUND: Antibodies to high-frequency antigens in red blood cells make antibody identification difficult for immunohaematology laboratories to conduct using conventional methods, especially when the sample contains multiple co-existing allo-antibodies. This study presents the successful application of an antibody inhibition method based on recombinant blood group antigens (rBGAs) to identify mixtures of allo-antibodies as well as an antibody to a high-frequency antigen observed in two patients. METHODS: rBGAs were utilised in detecting antibodies in two samples where more than one antibody was inhibited simultaneously from polyreactive plasma. The inhibition step was followed using conventional column agglutination techniques. RESULTS: In the sample of Patient A, anti-f and the previously missed anti-Jk^b were identified after simultaneous inhibition of anti-Yt^a and anti-Fy^a. The results of the sample of Patient B show anti-C and anti-M identified after simultaneous inhibition of anti-Ch1 and anti-Fy^a. CONCLUSIONS: The presented technique is an excellent supporting aid in antibody identification used with conventional column agglutination techniques. Antibody inhibition using mixed rBGAs allows reference and routine laboratories to identify rare antibody mixtures in a fast and efficient manner. Routine laboratories may be able to conduct difficult antibody identifications independently without referring these samples to a reference laboratory, resulting in faster identification results and elimination of delay in patient care. Simultaneous rBGA inhibition is an off-label technique not instructed in the user manual of rBGA and should be used with caution.