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Removing IgG antibodies from intact red cells: comparison of acid and EDTA, heat, and chloroquine elution methods
Author(s) -
Roziers N. Burin,
Squalli S.
Publication year - 1997
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1046/j.1537-2995.1997.37597293880.x
Subject(s) - elution , chemistry , agglutination (biology) , chromatography , antigen , antibody , abo blood group system , red cell , in vivo , immunology , medicine , biology , microbiology and biotechnology
BACKGROUND : To accurately phenotype red cell from patients with a positive direct antiglobulin test (DAT), nonlytic elution procedures were assessed for their ability to dissociate IgG from antibody‐coated red cells without altering red cell antigen expression. STUDY DESIGN AND METHODS : Antibodies coating red cells that were sensitized in vivo (warm‐reactive autoantibodies: 8 patients) or in vitro (42 alloantibodies) were eluted by using glycine‐HCl and EDTA (acid/EDTA), heat (56°C, 10 min), or chloroquine method. RESULTS : Acid/EDTA elution gave the best results, reducing DAT positivity to microscopic levels or rendering the DAT negative in 48 of 50 instances, whereas 4 samples remained resistant to heat elution and 24 to chloroquine. Standard DAT agglutination scores demonstrated that both acid/EDTA and heat elution were superior to the chloroquine method (p < 0.0001). With the gel low‐ionic‐strength saline indirect antiglobulin test, acid/ EDTA was superior to heat (p < 0.001). Overall, acid/ EDTA elution dissociated more antibodies than heat (p < 0.0001), especially for Kell system (K, k, Kp a , Kp b ) alloantibodies. Common red cell antigens, other than Kell system antigens, were unaffected by acid/EDTA elution. In contrast, the expression of most blood group antigens was diminished after heat elution. However, it was possible to type red cell antigens by using gel low‐ionic‐strength saline indirect antiglobulin tests or tube agglutination methods. CONCLUSION : Although heat elution may be used on a limited basis, the acid/EDTA method appears to be the procedure of choice for typing red cell coated with warm‐reactive IgG alloantibodies or autoantibodies.