Alloantibody

These are antibodies that recognize non-self antigens. An example: Alloantibodies can develop in patients who have received prior transfusions. Hence, having formed antibodies to non-self red blood cell antigens (e.g. anti-Kell, etc.). If a patient develops an alloantibody to Kell positive RBCs, the next time this patient receives a Kell positive RBC transfusion, he or she may adversely react to the transfused blood and develop a hemolytic transfusion reaction which could be fatal. This is a major reason for testing patient's blood prior to transfusing them with blood products.