These antigenes are not only on the erythrocyte surface, they are on many different cell systems in the body. Most people have the blood type 0, followed by groups A, B and AB.
Which antigenes and antibodies are present?
In people with type 0 blood none of the principal antigenes occur on the RBCs. Theoretically type 0 blood is a universal donor. This blood has antibodies against A and B. A person with AB blood has both A and B antigens on the RBCs. This blood contains no antibodies against A or B antigens. People with AB blood are also called universal recipients, because of the missing antibodies.
Note that a person born with one type of AB0 antigens has the antibodies against the other antigen, although they had never contact with the other type of blood.
What happens if a patient…