Answer
- A person with Rh positive blood contains Rh antigens (D
antigens).
- A person with Rh negative blood contains Anti-Rh
antibodies.
- When a person with Rh negative blood comes in contact
with Rh positive blood, it gets sensitized.
Example :
- When a Rh negative mother, conceive child with Rh positive
blood, the immune cells in mother's body identify Rh antigens as
foreign.
- They are sensitized to the fetal blood and produce anti-Rh
antibodies.
- When the mother conceive second child with Rh positibe blood,
these antibodies cross the placenta and attack red blood cells of
the fetus.
- This leads to destruction of RBC's of fetal blood.
Also, Rh negative person cannot receive blood from a Rh positive
person. Anti-Rh antibodies in the plasma of Rh negative person
cause transfusion reaction. Agglutinition may occur leading to
clumping of RBC's in the recepient.