Alloimmunization

the reaction of the immune system to foreign antigens, by formation of alloantibodies

Description
A patient may be exposed to foreign antigens through transfusion or transplantation. and pregnant women through transplacental transfer of fetal cells. Patients who need repeated transfusions should receive blood products as closely matched to their own blood type as possible. If the blood they receive is not a very close match, they can develop antibodies against antigens of the donated blood. This process is called alloimunization. To prevent alloimmunization, blood for multi-transfused patients must be closely matched. Often, this will mean testing blood samples from many blood donors or even a request to rare blood donor banks in order to find a match. For African-American sickle cell disease patients, the best match will most often come from donors of African descent.