A condition in which antibodies in a pregnant woman's blood cross the placenta and destroy her baby's red blood cells; it may develop when the mother and baby have differences in one or more blood group antigens

Substance (e.g., a toxin) or organism (e.g., an amoeba) that, when entering the body, causes the production of an antibody that reacts specifically with the antigen to neutralize, destroy, or weaken it. The presence of certain antigens is the criterion for typing in the ABO blood group system and is important in tissue cross-matching for...