Characterization of an anti-Dia antibody causing hemolytic disease in a newborn infant

A case of hemolytic disease in a newborn infant caused by anti-Dia is described. The parents are Japanese. The antibody was an IgG of subclasses IgG1 and IgG3, did not bind complement, and gave a 27 percent phagocytosis rate when used to sensitize red blood cells for a macrophage binding assay. The antibody was not detected during antenatal serologic testing. This case suggests the need for reagent red blood cell panels selected to match antibody specificities likely to be encountered in a particular population.