Overview Different classes of blood antigens and antibodies result in different blood groups RBC surface antigens A B Rh (D antigen) plasma antibodies Anti-AB antibodies IgM (do not cross placenta) Anti-Rh antibodies IgG (cross placenta) can result in Rh Hemolytic Disease of the Newborn (Rh HDN) Blood groups Blood group RBC surface antigen Plasma antibody Comments A A B B B A AB A and B None "Universal recipient" O Neither A nor B Both A and B "Universal donor" Rh + indicates presence of Rh antigen - indicates absence of Rh antigen Pathology Transfusion reactions when incompatible blood is given severe immunologic reactions occur presents with hemolysis renal failure shock death