Genesis of ABO blood group system
The ABO system discovered by Landsteiner in 1901 is clinically most significant and is of great importance in transplantation immunology and transfusion medicine. The ABO grouping is the single most important serological test performed in compatibility testing. It is a major blood group system with enormous diversity consisting of three carbohydrate antigens (A, B and H) under the control of A & B genes (of 175 alleles) present on the chromosome 9. The organ/tissue transplantation and blood transfusion depends on the successful matching of these blood groups. These antigens are widely distributed and are present not only on RBCs and platelets but also on endothelial cells of various tissues in human body. An interesting co-evolutionary relationship exists between the ABO blood group system and the useful microbial flora (bacteria) in human body. As far as their development is concerned, the A and B antigens are produced by the addition of N-acetylgalactosamine (UDP-GalNAc) and ...