ABO and H blood group systems

This chapter discusses the ABO and H blood group system. The ABO blood group system consists of the A; B; A,B and A antigens and anti-A and anti-B antibodies are mentioned to be most clinically significant in transfusion practice. These reciprocal antibodies are consistently present in the sera of the majority of individuals without previous red blood cell (RBC) exposure and these antibodies may result in severe intravascular hemolysis after transfusion of ABO-incompatible blood components. The prevention of ABO-incompatible transfusion is the primary objective pre-transfusion testing. The ABO antigens are carbohydrate structures and it may be A or B or H antigen types. Antibodies to the antigens, anti-A and anti-B are found in the plasma of individuals who lack the corresponding antigen. The group O individuals form anti-A and anti-B, group A individuals form anti-B, group B individuals will form anti-A and group AB individuals form neither antibody. The anti-A and anti-B titer results are used in a variety of clinical situations, including evaluation of ABO mismatch platelet components, ABO-incompatible solid organ transplantation and ABO mismatched hematopoietic progenitor cell transplantation.

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Author Beth H. Shaz Pathology