Blood group A antigen (A antigen) (A antigen)

The Blood group A antigen is a terminal carbohydrate structure found on the surface of red blood cells and vascular endothelial cells, including those within the kidney [1]. It is synthesized by the ABO glycosyltransferase, which adds an N-acetylgalactosamine residue to the H antigen precursor [1]. In clinical medicine, this antigen is a critical barrier to ABO-incompatible kidney transplantation, as pre-existing anti-A antibodies in the recipient can bind to the donor's vascular endothelium [2]. This binding triggers the classical complement pathway, resulting in endothelial injury, microvascular thrombosis, and potentially hyperacute graft rejection [2][3]. Current therapeutic approaches focus on depleting recipient antibodies or using B-cell-targeted therapies like Rituximab [3]. Emerging experimental techniques involve the ex vivo perfusion of donor kidneys with specific glycosidases, such as alpha-N-acetylgalactosaminidase, to enzymatically remove the A antigen and convert the organ to a universal blood type O phenotype before transplantation [4].

Other names

Histo-blood group A antigenA substanceBlood group A carbohydrateA antigen on kidney vascular endothelium

Enzymatic hydrolysis of the terminal N-acetylgalactosamine residue to eliminate the antigenic epitope; Complement-dependent cytotoxicity (CDC) following antibody binding.