Measurement of posttransfusion red cell survival with the biotin label

Abstract

The goal of this review is to summarize and critically assess information concerning the biotin method to label red blood cells (RBC) for use in studies of RBC and transfusion biology-information that will prove useful to a broad audience of clinicians and scientists. A review of RBC biology, with emphasis on RBC senescence and in vivo survival, is included, followed by an analysis of the advantages and disadvantages of biotin-labeled RBC (BioRBC) for measuring circulating RBC volume, posttransfusion RBC recovery, RBC life span, and RBC age-dependent properties. The advantages of BioRBC over (51)Cr RBC labeling, the current reference method, are discussed. Because the biotin method is straightforward and robust, including the ability to follow the entire life spans of multiple RBC populations concurrently in the same subject, BioRBC offers distinct advantages for studying RBC biology and physiology, particularly RBC survival. The method for biotin labeling, validation of the method, and application of BioRBCs to studies of sickle cell disease, diabetes, and anemia of prematurity are reviewed. Studies documenting the safe use of BioRBC are reviewed; unanswered questions requiring future studies, remaining concerns, and regulatory barriers to broader application of BioRBC including adoption as a new reference method are also presented.

Keywords: Application; Biotin; Multiple density; Nonradioactive; Red cell survival; Red cell volume; Vulnerable population.

Figure 1

Survival of autologous BioRBCs data from a healthy adult in erythropoietic steady state illustrating PTR₂₄, T₅₀, and mean potential lifespan as defined in the accompanying text [57]. Depicted is the decline enrichment RBC biotinylated at a single low density (6 μg of biotinylating reagent per mL of RBC).

Figure 2

Representative flow cytometric histogram of multidensity BioRBC. In a histogram of the number of RBC versus fluorescent intensity per RBC, five discrete RBC populations (four BioRBC and one unlabeled RBC) are observed in a venous blood sample after infusion of a mixture of BioRBCs labeled individually at 4 discrete biotin densities.

Figure 3

Post-transfusion RCS decreases with increasing BioRBC densities. Comparison of RCS concurrently studied with four separate 3-fold increasing densities of BioRBC. Panel A: Mean data for autologous RBC of eight normal adults as reported by Mock et al. [57]. The two highest densities yielded significant progressive shortening of long-term RCS. Panel B: Mean data of allogeneic BioRBC for nine very low birth weight infants are compared to non-manipulated Kidd antigen mismatched RBC as reported by Widness et al. [59]. The three lowest BioRBC densities track well with Kidd antigen, but the highest density BioRBC resulted in a significantly accelerated decline in tracking.

Figure 4

Potential safety issues encountered in the preparation and administration of BioRBC. Bold font indicates actions to be taken to improve safety.