Hematologic features which may influence Rh immunization.

The biologic features which may influence Rh sensitization in the mother and hemolytic disease in the newborn are conditioned by the hereditary immunologic pattern of the subjects, the antigenic characteristic of the blood group specific substances, the character of the antibody responses, the inherent susceptibility to disease as a result of the immune mechanism, and the character and sequence of exposure to the antigenic substance. In respect to Rh-negative women, there appears to be a greater vulnerability to immunization among those of blood group A. In regard to the infant, the compatibility of the maternal-infant blood types and the part they play in the phenomenon of the competition of antigens may influence the occurrence of hemolytic disease in the newborn.