An autoanalyzer test to determine immunoglobulin class and IgG subclass of blood group antibodies

An automated antiglobulin test was used to characterize the immunoglobulin class and IgG subclass of red blood cell-bound antibodies. Immunoglobulin classes and IgG subclasses of some clinically significant antibodies (anti-D and anti-CD, anti-Fy, anti- Jka) as well as of clinically insignificant anti-Chido antibodies were determined. Eighteen anti-Duffy antibodies were structurally homogeneous, and were mostly composed only of IgG1. Of the 16 anti-Fya antibodies studied only three had IgG2, and four had IgM molecules. Ten anti-Jka antibodies were heterogeneous, but all samples were either IgG1 or IgG3, or both. The most prominent immunoglobulin of 12 hyperimmune anti-Rh (anti-D and anti-CD) antibodies was IgG1. Under the conditions of our test, we also detected IgG3 and very low concentrations of IgG2 and IgG4 molecules in the anti-Rh antibodies.