Is there a clinical need for a diagnostic test allowing detection of chain type-specific anti-A and anti-B?
BACKGROUND
Hemagglutination for detection and semiquantification of ABO antibodies is associated with large center-to-center variations and poor reproducibility. Because acceptance for transplantation and diagnosis of rejection in ABO-incompatible transplantation rely on the levels and specificity of ABO antibodies, reproducible tests that allow their detection and specificity determination are required.


METHODS
The level of chain type-specific anti-A and anti-B were analyzed in the sera of 44 healthy individuals of known ABO blood group using an enzyme-linked immunosorbent assay (ELISA) with polyacrylamide (PAA) conjugates of blood group A and B trisaccharides or Type 2 chain A and B tetrasaccharides. Selected sera were further analyzed by hemagglutination and in an ELISA with Types 1 to 4 chain A or B neoglycolipids (NGL) as antigens.


RESULTS
Immunoglobulin (Ig)G anti-A and anti-B levels were higher (p ≤ 0.05) in blood group O than in B and A individuals. More IgM anti-A and anti-B cross-reactivity was detected in AB serum on PAA-conjugated A and B trisaccharides than on the tetrasaccharides. One of 11 blood group B and two of 12 A individuals had IgG antibodies binding the tetrasaccharide despite lack of, or very low reactivity with, the trisaccharides. IgG antibodies preferring the A and B Type 2 tetrasaccharides were of the IgG2 subclass. The NGL ELISA further supported the presence of chain type-specific anti-A and -B antibodies among nonsensitized, healthy individuals.


CONCLUSIONS
An ELISA with structurally defined ABH antigens will allow the antibody class and fine specificity of ABO antibodies to be determined, which may improve risk assessment in ABO-incompatible transplantation.
Lindberg
Linda
L
AbSorber AB and the Division of Clinical Immunology and Transfusion Medicine, Karolinska Institute, Stockholm, Sweden.
Johansson
Sandra M
SM
Liu
Jining
J
Grufman
Per
P
Holgersson
Jan
J
D000017:ABO Blood-Group System / Q000737:chemistry / Q000276:immunology*; D001782:Blood Donors; D001787:Blood Group Incompatibility; D004797:Enzyme-Linked Immunosorbent Assay; D006386:Hemagglutination Tests; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007518:Isoantibodies / Q000097:blood*
D000017:ABO Blood-Group System; D007074:Immunoglobulin G; D007518:Isoantibodies