Main erythrocyte antigens involved in the alloimmunization process

Erythrocyte alloimmunization occurs when an individual produces antibodies to antigens on the donor's red blood cell, which the immune system identifies as a foreign element to the organism. It represents one of the greatest risks faced by patients undergoing transfusion therapy, reducing the possibility of finding compatible red blood cells in future transfusions. The immune system of the human being has the ability to recognize what is proper to its genome from what is not proper, being able to stimulate an immune reaction against foreign substances. Upon contact with different antigens present in the donor red blood cell, the recipient of the blood may trigger an immune response by generating antibodies against nonself antigens due to sensitization, such as post-pregnancy or primary transfusion, which may trigger lysis of transfused red blood cells. Exposure to large numbers of nonself antigens may lead to the formation of alloantibodies causing intra- or extravascular haemolytic transfusion reaction. Polytransfused patients are more likely to develop alloantibodies, approximately 1% for each transfused unit. This percentage may be higher in sickle cell patients (36%), thalassemia patients (10%) and people with myelo and lymphoproliferative diseases (9%)