The measurement of the total volume of red cells in man: a non‐radioactive approach using biotin

Abstract

Present methods for measuring red cell volume are based on the dilution of radioactively labelled cells. This precludes the investigation in neonates and pregnant women. We present a simple method for labelling red cells with biotin. These cells may be injected intravenously and subsequently detected using streptavidin‐FITC and flow‐cytometry. A comparison of the red cell volume estimated using both 51Cr and biotin labelled cells in 19 patients showed no consistent clinically significant difference between the two. This novel label appears to allow red volume to be reliably estimated without using radioactivity.

Development, validation, and potential applications of biotinylated red blood cells for posttransfusion kinetics and other physiological studies: evidenced‐based analysis and recommendations

“…Failure to adequately wash whole blood substantially and unpredictably decreases the number of biotin labels per RBC. The resultant BioRBC product may be unsuitable for determining RCS . The final postbiotinylation wash step removes potentially toxic unreacted sulfo‐NHS‐biotin, reaction byproducts, and hydrolysis products from the final BioRBC suspension (see “Safety issues for BioRBCs”).…”

Drug delivery by red blood cells: vascular carriers designed by mother nature

“…One of such applications, namely, isolation and tracing of subpopulations of RBC in circulation165,166 as well as monitoring their survival167 and volume168, had found use in animal169,170 and human studies involving injection of normal, senescent and sickle-cell biotinylated RBC171,172. Furthermore, methods for direct biotinylation of RBC in the bloodstream using intravascular injection of biotin esters have been explored170,173 (this method likely yielded promiscuous modification of diverse blood cells and endothelium).…”

Modeling transfusion reactions and predicting in vivo cell survival with kodecytes

“…From the perspective of this paper, these previous pioneering RBC biotinylation reports established the utility and principles that biotinylation per se of RBCs does not appear to significantly affect the survival of the RBC and biotin attached to RBCs is prima facie safe 2,3,11,12,14,15 although survivals may be slightly reduced 3 or affected by avidin (egg) intake 2,15 …”

“…Although this technique is relatively simple, it suffers from several disadvantages particularly in that it uses radioactive compounds and that survival curves have to be corrected 1 . An alternative technique of covalently biotinylating RBCs has been utilized both in animals 11‐14 and in humans 2,3,14 . Although this promising technique shows equivalent cell survivals 2,3,11,12,15 to the 51 Cr method, it does not appear to have become widely utilized, perhaps due to its perceived risks associated with the transfusion of cells with untargeted chemically modified surfaces (biotin reacts with available epsilon amino and similar residues) and risks of any residual chemical reactants.…”

“…Radioisotope chromium 51 ( 51 Cr) labeling of blood, despite its disadvantages, is still the only reliable method to predict the intravascular success of an incompatible transfusion 1 . Alternative techniques such as direct biotinylation of red blood cells (RBCs), 2,3 despite their promise, have not been routinely adopted. Exposure of recipients or blood to chemicals (or radiation), and ensuring the modified cells are functionally unaffected by the modification, 1 together with specialized and laborious techniques are potential reasons why cell survival studies are not more routinely used.…”