Reactions to Differences in Donor Blood Unless you are transfused with your own blood or have an identical twin who donated blood for you to use, the blood you receive will contain many things that are foreign to you. This is true even when the blood is correctly cross-matched.
The donor's blood—the red and white blood cells , platelets and even plasma proteins—will all have antigens (proteins) your body will have never come in contact with before. What usually happens when you are exposed to foreign antigens is that your immune system reacts. After all, the system is designed to recognize and try to destroy anything foreign that gets into our bodies, especially invading germs such as bacteria or viruses. Fortunately, the immune system rarely recognizes most of the differences between a donor's blood and your own.
Differences in Red Blood Cells These are the most critical. While there are more than 400 recognized differences, only three are of practical importance. These have to do with certain antigens, namely the A, B and D antigens that determine your ABO and Rh blood types.
Antibodies are part of the immune response to foreign antigens. If you have type B blood, you have anti-A antibodies, so if you are transfused with Type A red cells, those cells will be destroyed. Not only will the transfusion not accomplish its purpose but you may experience chills, fever, aches and pains and in rare cases shock, bleeding, even death. Blood banks and hospital transfusion services do repeated tests and checks to be sure patients don't receive blood with the wrong ABO type.
