Accelerated removal of antibody-coated red blood cells from the circulation is accurately tracked by a biotin label.
BACKGROUND
Safe, accurate methods to reliably measure circulating red blood cell (RBC) kinetics are critical tools to investigate pathophysiology and therapy of anemia, including hemolytic anemias. This study documents the ability of a method using biotin-labeled RBCs (BioRBCs) to measure RBC survival (RCS) shortened by coating with a highly purified monomeric immunoglobulin G antibody to D antigen.


METHODS
Autologous RBCs from 10 healthy D+ subjects were labeled with either biotin or (51) Cr (reference method), coated (opsonized) either lightly (n = 4) or heavily (n = 6) with anti-D, and transfused. RCS was determined for BioRBCs and for (51) Cr independently as assessed by three variables: 1) posttransfusion recovery at 24 hours (PTR(24) ) for short-term RCS; 2) time to 50% decrease of the label (T(50) ), and 3) mean potential life span (MPL) for long-term RCS.


RESULTS
BioRBCs tracked both normal and shortened RCS accurately relative to (51) Cr. For lightly coated RBCs, mean PTR(24) , T(50) , and MPL results were not different between BioRBCs and (51) Cr. For heavily coated RBCs, both short-term and long-term RCS were shortened by approximately 17 and 50%, respectively. Mean PTR(24)  by BioRBCs (84 ± 18%) was not different from (51) Cr (81 ± 10%); mean T(50)  by BioRBCs (23 ± 17 days) was not different from (51) Cr (22 ± 18 days).


CONCLUSIONS
RCS shortened by coating with anti-D can be accurately measured by BioRBCs. We speculate that BioRBCs will be useful for studying RCS in conditions involving accelerated removal of RBCs including allo- and autoimmune hemolytic anemias.
Department of Biochemistry & Molecular Biology and the Department of Pediatrics, University of Arkansas for Medical Sciences, 4301W Markham Street, Little Rock, AR 72205, USA. mockdonaldm@uams.edu
Donald M
DM
Mock
Gary L
GL
Lankford
Nell I
NI
Matthews
Leon F
LF
Burmeister
Daniel
D
Kahn
John A
JA
Widness
Ronald G
RG
Strauss
D001710:Biotin; D002470:Cell Survival; D002860:Chromium Radioisotopes; D004912:Erythrocytes / Q000502:physiology*; D006801:Humans; D007518:Isoantibodies / Q000276:immunology*; D018029:Rho(D) Immune Globulin
D002860:Chromium Radioisotopes; D007518:Isoantibodies; C061961:RHO(D) antibody; D018029:Rho(D) Immune Globulin; D001710:Biotin