ABO blood group system
[2][3] A mismatch in this serotype (or in various others) can cause a potentially fatal adverse reaction after a transfusion, or an unwanted immune response to an organ transplant.
The ABO blood types were discovered by Karl Landsteiner in 1901; he received the Nobel Prize in Physiology or Medicine in 1930 for this discovery.
It remains to be seen whether this appearance is related to inborn differences between individuals or it is the result of some damage of bacterial kind.
In his paper, he referred to the specific blood group interactions as isoagglutination, and also introduced the concept of agglutinins (antibodies), which is the actual basis of antigen-antibody reaction in the ABO system.
[13][14] Czech serologist Jan Janský independently introduced blood type classification in 1907 in a local journal.
Unknown to Janský, an American physician William L. Moss devised a slightly different classification using the same numerical;[16] his I, II, III, and IV corresponding to modern AB, A, B, and O.
As a member of a committee of the National Research Council concerned with blood grouping, he suggested to substitute Janský's and Moss's systems with the letters O, A, B, and AB.
(There was another confusion on the use of figure 0 for German null as introduced by Hirszfeld and von Dungern, because others used the letter O for ohne, meaning without or zero; Landsteiner chose the latter.
[10] Felix Bernstein demonstrated the correct blood group inheritance pattern of multiple alleles at one locus in 1924.
[20] Watkins and Morgan, in England, discovered that the ABO epitopes were conferred by sugars, to be specific, N-acetylgalactosamine for the A-type and galactose for the B-type.
People with weak alleles of A can sometimes express anti-A antibodies, though these are usually not clinically significant as they do not stably interact with the antigen at body temperature.
[citation needed] In the UK, the distribution of blood type frequencies through the population still shows some correlation to the distribution of placenames and to the successive invasions and migrations including Celts, Norsemen, Danes, Anglo-Saxons, and Normans who contributed the morphemes to the placenames and the genes to the population.
[citation needed] Some evolutionary biologists theorize that there are four main lineages of the ABO gene and that mutations creating type O have occurred at least three times in humans.
Anti-A antibodies are hypothesized to originate from immune response towards influenza virus, whose epitopes are similar enough to the α-D-N-galactosamine on the A glycoprotein to be able to elicit a cross-reaction.
The high within-population diversity observed in human populations would, then, be a consequence of natural selection on individuals.
[48][49] The ABO antigen is also expressed on the von Willebrand factor (vWF) glycoprotein,[50] which participates in hemostasis (control of bleeding).
The results of this study found that the occurrence was not affected by ADAMTS13 polymorphism, and the only significant genetic factor was the person's blood group.
[57] The significance of ABO(H) antigen expression on these other hemostatic glycoproteins is not fully defined, but may also be relevant for bleeding and thrombosis.
[60][61] Furthermore, the expression of ABO blood group antigens in normal human tissues is dependent the type of differentiation of the epithelium.
[62] Several studies have observed that a relative down-regulation of GTA and GTB occurs in oral carcinomas in association with tumor development.
[64] In addition, another large GWAS study has associated ABO-histo blood groups as well as FUT2 secretor status with the presence in the intestinal microbiome of specific bacterial species.
[67] A multi-locus genetic risk score study based on a combination of 27 loci, including the ABO gene, identified individuals at increased risk for both incident and recurrent coronary artery disease events, as well as an enhanced clinical benefit from statin therapy.
[74] Its popularity faded following Japan's defeat in World War 2 and Japanese support for eugenics faltered, but it resurfaced in the 1970s by a journalist named Masahiko Nomi.
As with blood type personality theory, these and other popular ideas lack scientific evidence, and many are discredited or pseudoscientific.
