What exactly would happen if a person of blood group A received blood from a person with blood group B during a transgusion?

Blood groups are determined by substances on the surface of the red blood cells called antigens.  Antigens are recognised by antibodies which bind to the antigens so they can be identified by the immune system and removed.  Therefore, if you have a certain blood type then you will not have antibodies to that blood type in your blood (otherwise you would destroy your own red blood cells).  So, people with blood group A have antibodies to B antigens (anti-B) and people with blood group B have anti-A antibodies. If a person of blood group A received blood from a blood group B donor during transfusion, then the anti-B antibodies in their blood would recognise the B antigens on the donor red blood cells and they would be destroyed by the immune system (as they are recognised as being foreign). This is termed a transfusion reaction and can range from minor to life-threatening.

Last edited by David Henley (1st Mar 2007 20:58:27)