What are the 3 key proteins in blood typing?

Question

Why are they important?

Answer 1

I know about two important proteins... Every red cell from the blood has on its surface either an A-type protein, or a B-type protein. They are used in determining your blood type and it's very important because if you receive a blood transfusion, you must receive blood that is compatible to yours. If blood from different groups is mixed together, the antibodies make the red blood cells stick together. Large clots form and can block blood vessels, and death can occur.

One blood type system is the ABO system. Every human being belongs to one of four blood types : A, B, AB, or O. Your blood type depends on which proteins, called antigens, are on the surface of your red blood cells--A-protein or B-protein--and which antibodies are in your plasma. If your blood cells have A-protein, your blood type is A. If your red blood cells have B-protein, your blood type is B. If your red blood cells have both A-protein and B-protein, your blood type is AB. If your red blood cells have neither A-protein or B-protein, your blood type is O.

Answer 2

Perhaps stating the obvious, but if my blood type is AB+ and yours is A+ and you get a transfusion of my blood, then your immune system will attack the B in the blood that you just got. There's a chance of about 1 in 14,000 that you'll get the wrong blood type!

Goodnough LT, et al. (2003). Transfusion medicine: Looking to the future. Lancet, 361(9352): 161–169.

A mild transfusion reaction can cause fever, hives, shortness of breath, pain, rapid heart rate, chills, and low blood pressure. If treated immediately, it's not life threatening. If you get the wrong blood type, this becomes a life threatening condition. So, if you're AB+, you're a universal recipient, meaning, you can get any type of blood and be fine. If you're O-, then you're a universal donor, meaning you can donate your blood to everyone.

Answer 3

Another type of protein in blood is Rh. People are either Rh+ or Rh-. This is important especially when an Rh- mother is having an Rh+ baby. She will develop antibodies against Rh proteins. These antibodies will not harm the first Rh+ child she has, but if she is having another one, the antibodies will attack the babies blood usually resulting in miscarriage.

(So the answer is A antigen, B antigen, and Rh)