Gel test assay for IgG subclass detection by GM typing: application to hemolytic disease of the newborn

The gel test assay was evaluated for IgG subclass detection by GM typing of antibodies and compared to the classical inhibition agglutination method on slides or microtiter plates. We used a panel of 5 murine monoclonal antibodies directed against G1M(1), G1M(3), G1M(17), G2M(23), and G3M(21) and 1 human polyclonal anti-G3M(5) antibody. Eleven polyclonal antisera (of immunized women) directed against red blood cells were tested for the GM allotypes carried by their alloantibodies. We controlled the specificity of the gel test reaction using a panel of anti-RH(D) monoclonal antibodies. All reagents exhibited a good reactivity and specificity. They can be used for routine typing. The gel test assay for IgG subclass detection is a specific, simple, and low-cost technique for the detection and management of severe forms of diseases in alloimmunized pregnancies.