ABO blood group system (ABO) (ABO)

The ABO blood group system is the primary classification system for human blood, defined by the presence of A and B carbohydrate antigens on the surface of red blood cells and other tissues. These antigens are produced by the ABO glycosyltransferase, which modifies the H antigen precursor by adding specific sugar residues (UniProt: P16442). Clinical significance arises from the presence of naturally occurring antibodies (isohemagglutinins) against missing antigens, which can trigger life-threatening immune responses during incompatible transfusions or organ transplants (StatPearls: ABO Blood Group System). Beyond transfusion medicine, the ABO system is linked to various pathological conditions, including an increased risk of venous thromboembolism in non-O individuals due to elevated von Willebrand factor levels (PubMed: 27535324). Furthermore, specific blood groups are associated with susceptibility to gastric cancer, pancreatic cancer, and certain infectious diseases like malaria (PubMed: 22037313). Therapeutic approaches involving this system focus on preventing or treating hemolytic reactions through antibody depletion, complement inhibition, or the use of ABO-compatible donor materials.

Other names

ABO glycosyltransferaseHisto-blood group ABO system transferaseA transferaseB transferaseH antigenA antigenB antigen

Therapeutic strategies focus on neutralizing or depleting anti-A or anti-B antibodies or inhibiting the complement system (C3 or C5) to prevent the destruction of red blood cells or transplanted organs expressing ABO antigens.