Comparison of flow cytometric assays with isotopic assays of (51)chromium-labeled cells for estimation of red cell clearance or survival in vivo

A comparison was made between flow cytometric and conventional radioisotopic assays in the determination of the clearance or survival of small volumes of (51)chromium-labeled D+ red cells after injection into volunteers. Four clearance studies were performed using 4 mL of autologous D+ cells coated...

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Bibliographic Details
Published in:Transfusion (Philadelphia, Pa.) Pa.), 2000-02, Vol.40 (2), p.228-239
Main Authors: Kumpel, B M, Austin, E B, Lee, D, Jackson, D J, Judson, P A, Chapman, G E
Format: Article
Language:English
Subjects:
Blood Volume
Chromium Radioisotopes
Erythrocyte Aging
Erythrocyte Transfusion
Erythrocytes - chemistry
Erythrocytes - metabolism
Flow Cytometry - methods
Humans
Immunoglobulin G - blood
Isotope Labeling - methods
Male
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Summary:A comparison was made between flow cytometric and conventional radioisotopic assays in the determination of the clearance or survival of small volumes of (51)chromium-labeled D+ red cells after injection into volunteers. Four clearance studies were performed using 4 mL of autologous D+ cells coated with anti-D at two concentrations (5 or 10 microg anti-D/mL red cells) transfused to two subjects at separate times. Five survival studies were carried out using 5 mL of frozen-thawed D+ cells transfused to five D- subjects with no detectable anti-D. Sequential blood samples were taken for gamma counting and flow cytometry. Several methods were used to stain the transfused red cells, and the data were analyzed by using three flow cytometers. The determination of red cell clearance or survival by radioactivity measurements gave results consistent with published data. However, none of the flow cytometric assays exhibited the necessary sensitivity or accuracy in quantitation of the rare events to provide reliable data for the calculation of the initial clearance rate, the red cell half-life, or the mean cell lifespan, although rough estimates of red cell clearance were obtained in some subjects. This inability to accurately enumerate rare fluorescence-labeled cells was due mainly to the presence of "background" events, which were a considerable problem in some samples, when the coating level of anti-D was less than 3000 molecules of IgG per cell. Flow cytometry may enable the crude estimation of the percentage of small volumes (
ISSN:0041-1132
DOI:10.1046/j.1537-2995.2000.40020228.x