Antibodies provoked by the transfusion of biotin-labeled red cells

BACKGROUND: Biotin-labeled (biotinylated) red cells (B-RBCs) offer a techni que by which to study RBC volume and circulating kinetics without in vivo r adiation. The immunogenicity of B-RBCs is undefined. STUDY DESIGN AND METHODS: To determine if biotinylation renders RBCs immuno genic, autologous B-RBCs were transfused to 20 healthy subjects, and plasma samples were obtained before transfusion and: serially for up to 6 months after transfusion. These serial samples, plus plasma from 20 normal control subjects not given B-RBCs, were screened for antibodies to B-RBCs by use o f an antiglobulin technique against aliquots of group O RBCs from a single donor-one aliquot biotinylated and one aliquot not biotinylated (i.e., test and control RBCs). Posttransfusion recovery and survival of B-RBCs were al so determined. RESULTS: Plasma from none of 20 normal nontransfused subjects reacted with B-RBCs. Similarly none of the 20 subjects given autologous B-RBC transfusio ns exhibited antibodies before transfusion. However, 3 of the 20 subjects t ransiently produced antibodies to B-RBCs after transfusion. Antibodies disa ppeared within 6 months in 2 of these 3 subjects and within 12 months in th e third. Antibody reactivity was not reduced by dithiothreitol, but in 2 of the 3 subjects, B-RBC antibodies were neutralized by incubation with bioti n solution. Circulating RBC kinetics were not altered in the 3 subjects wit h antibody. The significance of these observations is unclear, because anti bodies were just beginning to emerge during the studies. CONCLUSIONS: Biotinylation does not render RBCs reactive with normal human plasma (i.e., presumably does not evoke neoantigens). Transfused B-RBCs occ asionally provoke IgG antibodies in healthy subjects. Because the biologic effects of B-RBC antibodies currently are unknown, testing for them is reco mmended when multiple B-RBC transfusions are given to study RBC volume or c irculating kinetics.