Hemolytic disease in a newborn infant, the product of a first pregnancy, is reported. A combination of anti-E and anti-S is shown as the cause of the disease. In view of the absence of a previous antigenic stimulus, the antibodies present are most probably naturally occurring IgG antibodies.

Keywords: antibody identification, anti-E, anti-S, blood group antibodies, hemolytic disease of the newborn, naturally occurring antibody