Blood Types and Antigens

Blood Types and Antigens

• In blood type AB, both antigen A and antigen B are present on RBCs.
• Type O blood has neither antigen A nor antigen B on RBCs.

Antibodies in Plasma

• In type A blood, antibodies against antigen B are present in the plasma.
• In type B blood, antibodies against antigen A are present in the plasma.

Blood Transfusions

• It is crucial to know the blood type of an individual receiving a blood transfusion to avoid an adverse reaction.
• When type A donor blood is mixed with type B recipient blood, an adverse reaction occurs due to the presence of antibodies against antigen A in the recipient's plasma.
• When type A donor blood is mixed with type A recipient blood, no adverse reaction occurs.

Rh Blood Type and Pregnancy

• A person can become sensitized to Rh antigens through a blood transfusion or pregnancy.
• A previously Rh-negative person will develop anti-Rh antibodies if they receive a blood transfusion with Rh-positive RBCs.
• In an Rh-negative mother, the development of anti-Rh antibodies during pregnancy can harm the fetus.
• Anti-Rh antibodies can be triggered when an Rh-negative mother is pregnant with an Rh-positive fetus, a condition known as hemolytic disease of the newborn (HDN).

Rh Blood Type and Sensitization

• Erythroblastosis fetalis is the condition where the mother's immune system attacks a Rh-positive fetus.
• Rh-positive individuals have the Rh antigen on their RBCs, which can trigger an immune response in Rh-negative individuals.
• If an Rh-negative person receives a blood transfusion with Rh-positive RBCs, they can become sensitized to Rh antigens.