Can a donor with type AB blood give can give blood to someone else with a different blood type?
1 Answer
No - the presence of A and B proteins where they don't belong will set off an immune response.
Explanation:
The Immune System of the human body reads the proteins of cells and things to identify if it is supposed to be there or not. For each cell, those proteins are like an ID card - if you don't have the correct ID card, you can expect security will be called!
Blood type operates based on these proteins. Blood type A has a protein that says it's type A. Blood type B has a protein that says it's type B. Blood type AB has both of them, and blood type O has neither. In the world of blood donations, blood type O is referred to as a Universal Donor and blood type AB as a Universal Receiver.
When someone with blood type O (let's call that person Oscar) donates blood to someone with, say, type AB (let's call that person ABby, here's what happens: the type O blood is examined by ABby's Immune System. Since it doesn't have a protein (an ID card) that says it's wrong, the O blood is accepted by ABby's body.
Now let's turn the tables and ABby donates to Oscar: in this case, Oscar's Immune System looks at the AB blood and sees that the proteins/ID card are wrong and so the blood will be attacked and destroyed. That, in turn, can make a bad situation much worse (since no one receives a blood transfusion when they are healthy).
Here's a chart showing this:
More about the adverse reactions to this situation is here:
