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ABO blood group system

2007 Schools Wikipedia Selection. Related subjects: Health and medicine

   ABO blood group antigens present on red blood cells and IgM antibodies
   present in the serum
   ABO blood group antigens present on red blood cells and IgM antibodies
   present in the serum

   The ABO blood group system is the most important blood type system (or
   blood group system) in human blood transfusion. The associated anti-A
   antibodies and anti-B antibodies are usually IgM antibodies, which are
   usually produced in the first years of life by sensitization to
   environmental substances such as food, bacteria and viruses. ABO blood
   types are also present in some animals, for example apes such as
   chimpanzees, bonobos and gorillas.

ABO antigens

   Diagram showing the carbohydrate chains which determine the ABO blood
   group
   Diagram showing the carbohydrate chains which determine the ABO blood
   group

   The A antigen and the B antigen are derived from a common precursor
   known as the H antigen (or H substance). The H antigen is a
   glycosphingolipid ( sphingolipid with carbohydrates linked to the
   ceramide moiety). Since it lacks N-acetylneuraminic acid ( sialic acid)
   it is referred to as a globoside, not a ganglioside. In blood group O
   the H antigen remains unchanged and consists of a chain of galactose,
   N-Acetylglucosamine, galactose, and fucose attached to the ceramide. H
   antigens can be changed into A or B antigens by enzymes coded by the
   blood group A or B genes. Type A has an extra N-Acetylgalactosamine
   bonded to the galactose near the end, while type B has an extra
   galactose bonded to the galactose near the end.

   Individuals with Type A blood can accept blood from donors of type A
   and type O blood. Individuals with type B blood can receive blood from
   donors of type B and type O blood. Individuals with type AB blood may
   receive blood from donors of type A, type B, type AB, or type O blood.
   Type AB blood is referred to as the universal recipient. Individuals of
   type O blood may receive blood from donors of type O blood. Type O
   blood is called the universal donor.

   Antibodies are not formed against the H antigen, except by those with
   the Bombay phenotype.

   In ABH secretors, ABH antigens are secreted by most mucous-producing
   cells of the body interfacing with the environment, including lung,
   skin, liver, pancreas, stomach, intestines, ovaries and prostate.

History of discoveries

   The ABO blood group system is widely credited to have been discovered
   by the Austrian scientist Karl Landsteiner, who found three different
   blood types in 1900; he was awarded the Nobel Prize in Physiology or
   Medicine in 1930 for his work. Due to inadequate communication at the
   time it was subsequently found that Czech serologist Jan Janský had
   independently pioneered the classification of human blood into four
   groups, but Landsteiner's independent discovery had been accepted by
   the scientific world while Janský remained in relative obscurity.
   Janský's classification is however still used in Russia and states of
   former USSR (see below). In America Moss published his own (very
   similar) work in 1910.

   Landsteiner described A, B, and O; Decastrello and Sturli discovered
   the fourth type, AB, in 1902. Ludwik Hirszfeld and E. von Dungern
   discovered the heritability of ABO blood groups in 1910-11, with Felix
   Bernstein demonstrating the correct blood group inheritance pattern of
   multiple alleles at one locus in 1924.

Serology

   Anti-A and anti-B antibodies, which are not present in the newborn,
   appear in the first years of life. It is possible that food and
   environmental antigens (bacterial, viral or plant antigens) are similar
   enough to A and B glycoprotein antigens that antibodies created against
   the environmental antigens in the first years of life can cross react
   with ABO-incompatible red blood cells. Anti-A and anti-B antibodies are
   usually IgM, which are not able to pass through the placenta to the
   fetal blood circulation.

   The "Light in the Dark theory" however suggests that when budding
   viruses take with them host cell membranes (in particular from the lung
   and mucosal epithelium where they are highly expressed)they also take
   along ABO Blood antigens from those membranes, and may carry them into
   secondary recipients where these antigens can elicit a host immune
   response againts these non-self foreign blood antigens. These viral
   carried blood antigens may be responsible for priming newborns into
   producing neutralizing antibodies against foreign blood antigens.
   Support for this theory has come to light in recent experiments with
   HIV. HIV can be neutralized in "in-vitro" experiments using antibodies
   against blood group antigens specifically expressed on the HIV
   producing cell lines. The "Light in the Dark theory" suggests a new
   novel evolutionary hypothesis that there is true communal immunity,
   which has developed to reduce the inter-transmissibility of viruses
   within a population. It suggests that individuals in a population
   supply and make a diversity of unique antigenic moieties so as to keep
   the population as a whole more resistant to infection. A system set up
   ideally to work with variable recessive alleles.

ABO hemolytic disease of the newborn

   ABO blood group incompatibilities between the mother and child does not
   usually cause hemolytic disease of the newborn (HDN) because antibodies
   to the ABO blood groups are usually of the IgM type, which do not cross
   the placenta; however, sometimes IgG ABO antibodies are produced and a
   baby can develop ABO hemolytic disease of the newborn.

Inheritance

   A and B are codominant, giving the AB phenotype.
   A and B are codominant, giving the AB phenotype.
   Blood group inheritance
   Mother/Father  O        A           B         AB
   O             O    O, A        O, B        A, B
   A             O, A O, A        O, A, B, AB A, B, AB
   B             O, B O, A, B, AB O, B        A, B, AB
   AB            A, B A, B, AB    A, B, AB    A, B, AB

   Blood groups are inherited from both parents. The ABO blood type is
   controlled by a single gene with three alleles: i, I^A, and I^B. The
   gene encodes a glycosyltransferase - that is, an enzyme that modifies
   the carbohydrate content of the red blood cell antigens. The gene is
   located on the long arm of the ninth chromosome (9q34).

   I^A allele gives type A, I^B gives type B, and i gives type O. I^A and
   I^B are dominant over i, so ii people have type O, I^AI^A or I^Ai have
   A, and I^BI^B or I^Bi have type B. I^AI^B people have both phenotypes
   because A and B express a special dominance relationship: codominance,
   which means that type A and B parents can have an AB child. Thus, it is
   extremely unlikely for a type AB parent to have a type O child (it is
   not, however, direct proof of illegitimacy): the cis-AB phenotype has a
   single enzyme that creates both A and B antigens. The resulting red
   blood cells do not usually express A or B antigen at the same level
   that would be expected on common group A[1] or B red blood cells, which
   can help solve the problem of an apparently genetically impossible
   blood group.

   Evolutionary biologists theorize that the I^A allele evolved earliest,
   followed by O (by the deletion of a single nucleotide, shifting the
   reading frame) and then I^B. This chronology accounts for the
   percentage of people worldwide with each blood type. It is consistent
   with the accepted patterns of early population movements and varying
   prevalent blood types in different parts of the world: for instance, B
   is very common in populations of Asian descent, but rare in ones of
   Western European descent.)

Population data

   Distribution of blood types among various populations
   Population O A B AB
   Native South Americans 100% – – –
   British 46% 42% 9% 3%
   Irish 52% 35% 10% 3%
   French 43% 45% 9% 3%
   Hongkonger 40% 26% 27% 7%
   Vietnamese 45.0% 21.4% 29.1% 4.5%
   Australian aboriginals 44.4% 55.6% – –
   Germans 42.8% 41.9% 11.0% 4.2%
   Bengalis 22.0% 24.0% 38.2% 15.7%
   Saami 18.2% 54.6% 4.8% 12.4%
   Finns 31% 44% 17% 8%
   Romanians 34% 41% 19% 6%
   Russians 33% 36% 23% 8%
   Japanese 30% 40% 20% 10%
   African Americans 49% 27% 20% 4%
   Kenyan 60% 19% 20% 1%

   The distribution of the blood groups A, B, O and AB varies across the
   world according to the population or race. There are also variations in
   blood type distribution within human subpopulations.

   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
   Vikings, Danes, Saxons, Celts, and Normans who contributed the
   morphemes to the placenames and the genes to the population.

Association with von Wilebrand factor

   The ABO antigen is also expressed on the von Willebrand factor (vWF)
   glycoprotein, which participates in hemostasis (control of bleeding).
   In fact, having type O blood predisposes to bleeding, as 30% of the
   total genetic variation observed in plasma vWF is explained by the
   effect of the ABO blood group, and individuals with group O blood
   normally have significantly lower plasma levels of vWF (and Factor
   VIII) than do non-O individuals. In addition, vWF is degraded more
   rapidly due to the higher prevalence of blood group O with the Cys1584
   variant of vWF (an amino acid polymorphism in VWF): the gene for
   ADAMTS13 (vWF-cleaving protease) maps to the ninth chromosome (9q34),
   the same locus as ABO blood type. Higher levels of vWF are more common
   amongst people who have had ischaemic stroke (from blood clotting) for
   the first time. 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.

Bombay phenotype

   Individuals with the rare Bombay phenotype ( hh) do not express
   substance H on their red blood cells, and therefore do not bind A or B
   antigens. Instead, they produce antibodies to substance H (which is
   present on all red cells except those of hh genotype) as well as to
   both A and B antigens, and are therefore compatible only with other hh
   donors.

Nomenclature in Europe former USSR

   In parts of Europe the "O" in ABO blood type is substituted with "0"
   (zero), signifying the lack of A or B antigen. In the former USSR and
   Russia, blood types are referenced using numbers and Roman numerals
   instead of letters. This is Janský's original classification of blood
   types. It designates the blood types of humans as I, II, III, and IV,
   which are elsewhere designated, respectively, as O, A, B, and AB. The
   designation A and B with reference to blood groups was proposed by
   Hirszfeld.

Examples of ABO and Rhesus D slide testing method

   Blood group O positive: neither anti-A nor anti-B have agglutinated,
   but anti-Rh has

   Result: Blood group B negative: anti-A and anti-Rh have not
   agglutinated but anti-B has

   In the slide testing method shown above, three drops of blood are
   placed on a glass slide with liquid reagents. Agglutination indicates
   the presence of blood group antigens in the blood.

Universal blood created from other types

   In April 2007 an international team of researchers announced in the
   journal Nature Biotechnology an inexpensive and efficient way to
   convert types A, B and AB blood into type O. This is done by using
   glycosidase enzymes from specific bacteria to strip the blood group
   antigens from red blood cells. The removal of A and B antigens still
   does not address the problem of the Rhesus blood group antigen on the
   blood cells of Rhesus positive individuals, and so blood from Rhesus
   negative donors must be used. Patient trials will be conducted before
   the method can be relied on in live situations.
   Retrieved from " http://en.wikipedia.org/wiki/ABO_blood_group_system"
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