Hemolytic disease of the newborn (HDN) is a disorder in which the red blood cells of a fetus are attacked and destroyed by maternal antibodies while in utero. This can result in
anemia, heart failure, and can be fatal in extreme circumstances.
HDN is only a concern when the mother's blood type is Rh, and the fetus is the second
child to be Rht. This makes it possible for the mother to have anti-Rht-antigens that will
diffuse across the placenta into the fetal blood stream.
1. Describe the role of macrophages in non-specific defense and specific defense the first
time the mother is exposed to Rhantigens. (1 mark)