Explain Rh Incompatibility

Rh compatibility sometimes leads to complications which are generally not seen with other types of mismatched transfusions. If a Rh negative is given Rh positive blood, there is no immediate adverse reaction because Rh negative individuals do not normally have anti-Rh antibodies which may damage the donor red cells. The donor red cells induce immune response in the recipient, as a result of which anti-Rh antibodies are synthesized. It takes 2-4 months before a high tirtre of anti-Rh antibodies are achieved.

By this time, most of the donor cells die a natural death. The anti-Rh antibodies can do no harm. Hence, first phase of transfusion passes silently. If the second dose is given, the memory cells ensure anti-Rh antibodies are synthesized in proper amounts. Second transfusion acts as a booster dose. High dose of anti-Rh antibodies can be achieved. Donor cells are thus damaged. Since anyone may need a second blood transfusion later in life, Rh negative individuals should never be given Rh positive blood.