IgG subclass distribution of anti-Rh, anti-Kell and anti-Duffy antibodies measured by sensitive haemagglutination assays.

The IgG subclass distribution of anti Rh antibodies (anti-D, 'anti-Du', anti-c, anti-E), anti-Kell and anti-Duffy (anti-Fya) antibodies was measured by two haemagglutination techniques on microtitre plates. The first technique involved rabbit subclass specific antisera which were used to agglutinate red cells previously reacted with the patients' antibodies at high concentration. The second, which was more sensitive, had an additional step by introducing sheep anti-rabbit antibodies (sandwich technique). By the sensitive sandwich technique we revealed, for anti-D antibodies: IgG1 8/19, IgG3 1/19, IgG1/IgG3 8/19, IgG1/IgG2/IgG3/IgG 41/19, IgG1/IgG4 1/19; for the Du reactive anti-D antibodies: IgG1 1/8, IgG1/IgG3 1/8, IgG1/IgG3/IgG4 6/8; for the anti-E antibodies: IgG1/IgG2/IgG4 2/3, IgG1/IgG2/IgG3/IgG4 1/3; for the anti-c antibodies: IgG1 2/5, IgG3 1/5, IgG1/IgG3 1/5; for the anti-Kell antibodies: IgG1 9/20, IgG1/IgG3 1/20, IgG1/IgG4 8/20, IgG1/IgG3/IgG4 2/20; and for anti-Duffy antibodies: IgG1 1/8, IgG1/IgG4 7/8. These results are partly at variance with previously published results.