View source for ABO blood group system

{{SI}}
'''Editor in Chief''': [[User:Fumiichiro Yamamoto|Fumichiro Yamamoto, Ph.D.]] [mailto:fyamamoto@burnham.org] Phone: 858-646-3116 



{{redirect3|H substance| For use in inflammation, see [[histamine]]}}

==Overview==
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 [[Blood type (non-human)|animals]], for example cows and sheep, apes such as chimpanzees, bonobos and gorillas.

== ABO Antigens ==
[[Image:ABO blood type.svg|thumb|left|300px|ABO blood group [[antigens]] present on [[red blood cells]] and [[IgM]] [[antibodies]] present in the [[serum]]]]
The A and B  [[antigens]] are derived from a common precursor known as the '''H antigen''' (or '''H substance'''). The H antigen is a carbohydrate sequence with [[carbohydrate]]s linked mainly to proteins (with a minor fraction attached to ceramide moiety).  The majority of the ABO determinants are expressed on the ends of long polylactosamine chains attached mainly to the Band 3 protein (1), the anion exchange protein of the red cell membrane. A minority of the epitopes are expressed on neutral glycosphingolipids (1). In blood group O the H antigen remains unchanged and consists of a chain of [[beta-D-galactose]], beta-D-N-Acetylglucosamine, beta-D-galactose, and 2-linked, alpha-L-fucose. The chain is attached to the protein or ceramide.  H antigens can be changed into A or B antigens by [[enzyme]]s coded by the blood group A or B genes, which are sugar (glycosyl) tranferases. Type A has an extra [[alpha-N-Acetyl-D-galactosamine]] bonded to the D-galactose at the end, while type B has an extra alpha-D-galactose bonded to the D-galactose at the end.

*Individuals with Type A blood can receive 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 can 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 with of type O blood can only receive blood from type O donors.
*Individuals of type A, B, AB and O blood can 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 [[Hh antigen system|Bombay phenotype]].

In ABH secretors, ABH antigens are secreted by most [[mucus]]-producing cells of the body interfacing with the environment, including lung, skin, liver, pancreas, stomach, intestines, ovaries and prostate.<ref>Laine, R.A. and Rush, J.S. (1988) "Chemistry of Human Erythrocyte Polylactosamine Glycopeptides (Erythroglycans) as Related to ABH Blood Group antigenic Determinants:  Evidence that Band 3 Carbohydrate on Human Erythrocytes Carries the Majority of ABH Blood Group Substance" in Molecular Immunology of  Complex Carbohydrates (A. Wu, E. Kabat, Eds.) Plenum Publishing Corporation, N.Y. NY.</ref>

== History of discoveries ==

The ABO blood group system is widely credited to have been discovered by Austrian scientist [[Karl Landsteiner]], who found three different blood types in 1900;<ref name=Landsteiner_1900>{{cite journal | author = Landsteiner K | title = Zur Kenntnis der antifermentativen, lytischen und agglutinierenden Wirkungen des Blutserums und der Lymphe | journal = Zentralblatt Bakteriologie | year = 1900 | volume = 27 | pages = 357–62 | url= }}</ref> in 1930, he was awarded the [[Nobel Prize in Physiology or Medicine]] 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,<ref name=Janský_1907>{{cite journal | author = Janský J| title = (Haematologick studie u. psychotiku | journal = Sborn. Klinick | language = Czech | year = 1907 | volume = 8 | pages = 85–139 | url= }}</ref> 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 both in Russia and in the states of the former U.S.S.R (see below). In the United States of America, Moss published his own (very similar) work in 1910.<ref name=Moss_1910>{{cite journal | author = Moss WL | title = Studies on isoagglutinins and isohemolysins | journal = Bulletin Johns Hopkins Hospital | year = 1910 | volume = 21 | pages = 63–70 | url= }}</ref>

Several other landmark discoveries have been made in the ABO blood type rsearch in the past century. As described above, Landsteiner described A, B, and O in his research; Decastrello and Sturli discovered the fourth ABO blood type, AB, in 1902.<ref name=von_Decastello_1902>{{cite journal | author = von Decastello A, Sturli A | title = Ueber die Isoagglutinine im Serum gesunder und kranker Menschen | journal = Mfinch med Wschr | year = 1902 | volume = 49| pages = 1090–5 | url= }}</ref> [[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 [[allele]]s at one locus in 1924. <ref name="Crow">{{cite journal |author=Crow J |title=Felix Bernstein and the first human marker locus |journal=Genetics |volume=133 |issue=1 |pages=4-7 |year=1993 |pmid=8417988}} {{PMC|1205297}}</ref>.  Watkins and Morgan, in England, determined that ABO epitopes were conferred by sugars, specifically N-acetylgalactosamine for the A-type and galactose for the B-type (Morgan, W. T. J. & Watkins, W. M. Br. Med. Bull. 25, 30−34 (1969), Watkins, W. M. in: Advances in Human Genetics Vol. 10 (eds Harris, H. & Hirschhorn, K.) 1−136 (Plenum, New York, 1980), Watkins, W. M. & Morgan, W. T. J. Vox Sang. 4, 97−119 (1959). After much published literature claiming that the ABH substances were all attached to glycosphingolipids, Laine's group (1988) found that the band 3 protein expressed a long polylactosamine chain (Jarnefelt, Rush, Li, Laine, J. Biol. Chem. 253: 8006-8009(1978)) which contained the major portion of the ABH substances attached (Laine and Rush in Molecular Immunology of  Complex Carbohydrates (A. Wu, E. Kabat, Eds.) Plenum Publishing Corporation, N.Y. NY (1988)). Later, Yamamoto, Clausen, and Hakomori (Yamamoto, et al.,Nature 345, 229 - 233 (1990)), showed the precise glycosyl transferase set that confers the A, B and O epitopes.

== Serology ==
[[Image:ABO blood group diagram.svg|thumb|left|300px|Diagram showing the carbohydrate chains which determine the ABO blood group]]
Anti-A and anti-B antibodies, which are not present in the newborns, appear in the first years of life. It is possible that food and environmental antigens ([[bacterium|bacteria]]l, [[Virus|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]], antibodies that are not able to pass through the [[placenta]] to [[fetal]] blood circulation.

When budding viruses take host cell membranes from a human patient (in particular from the lung and mucosal epithelia, where they are highly expressed), they also acquire ABO blood antigens from those membranes. As such, these viruses may carry the antigens into secondary recipients where they can elicit a host immune response. These viral-carried human-blood antigens may be responsible for priming newborns into producing neutralizing antibodies against foreign blood antigens. Support for this theory, named later as the "Light in the Dark theory" (DelNagro, 1998), has had particular application in 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. <ref>
{{cite journal
  | last = Arendrup
  | first = M
  | authorlink =
  | coauthors = Hansen JE, Clausen H, Nielsen C, Mathiesen LR, Nielsen JO
  | title = Antibody to histo-blood group A antigen neutralizes HIV produced by lymphocytes from blood group A donors but not from blood group B or O donors.
  | journal = AIDS
  | volume = 5
  | issue = 4
  | pages = 441-4
  | publisher =
  | date = 1991 Apr
  | url = 
  | doi =
  | id = PMID 1711864
  | accessdate =  }}
</ref>
<ref>
{{cite journal
  | last = Neil
  | first = SJ
  | authorlink =
  | coauthors = McKnight A, Gustafsson K, Weiss RA
  | title = HIV-1 incorporates ABO histo-blood group antigens that sensitize virions to complement-mediated inactivation
  | journal = Blood
  | volume = 105
  | issue = 12
  | pages = 4693-9
  | publisher =
  | date = 2005 Jun 15
  | url = http://bloodjournal.hematologylibrary.org/cgi/content/full/105/12/4693
  | doi =
  | id = PMID 15728127
  | accessdate =  }}
</ref>

The "Light in the Dark theory" suggests a new novel evolutionary hypothesis, namely that there is true communal immunity that has developed to reduce the inter-transmissibility of viruses within a population. It suggests that individuals in a population both produce and supply a diversity of unique antigenic moieties so as to keep the overall population more resistant to infection.  This system is ideally set up to work with variable recessive [[allele]]s.

== ABO hemolytic disease of the newborn ==
{{main|Hemolytic disease of the newborn (ABO)}}

ABO blood group incompatibilities between mother and child do not usually cause [[hemolytic disease of the newborn]] (HDN), because antibodies to 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 ==

[[Image:Codominant.jpg|thumb|left|130px|A and B are [[codominant]], giving the AB [[phenotype]].]]

{| class = "prettytable" style = "float:left; font-size:85%; margin-left:20px"
| colspan="5"|'''Blood group inheritance'''
|-
!  "text-align: center"|Mother/Father
! |'''O'''
! |'''A'''
! |'''B'''
! |'''AB'''
|-
| style="text-align: center"| '''O''' || O || O, A || O, B || A, B
|-
| style="text-align: center"| '''A''' || O, A || O, A || O, A, B, AB || A, B, AB
|-
| style="text-align: center"| '''B''' || O, B || O, A, B, AB || O, B || A, B, AB
|-
| style="text-align: center"| '''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 [[allele]]s: ''A'', ''B'', and ''O''. 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 [[Chromosome 9 (human)|ninth chromosome]] (9q34).

''A'' [[allele]] gives type A, ''B'' gives type B, and ''O'' gives type O. ''A'' and ''B'' are dominant over ''O'', so ''OO'' people have type O, ''AA'' or ''AO'' have A, and ''BB'' or ''BO'' have type B. ''AB'' people have both [[phenotype]]s because A and B express a special dominance relationship: [[codominance]], which means that type A and B parents can have an AB child. A type A and a type B couple can also have a type O child if they are both heterozygous (''AO'' and ''BO'') Therefore, in this case, a child with blood type O is not 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 antigens at the same level that would be expected on common group A<sub>1</sub> or B red blood cells. This distinction can help solve the problem of an apparently genetically impossible blood group.<ref name=Yazer=2006>{{cite journal |author=Yazer M, Olsson M, Palcic M |title=The cis-AB blood group phenotype: fundamental lessons in glycobiology |journal=Transfus Med Rev |volume=20 |issue=3 |pages=207-17 |year=2006 |pmid=16787828}}</ref>

One prominent theory suggests that type O evolved earliest, supported by the fact that all human beings can receive type O blood. The British National Blood Transfusion Service supports this theory (see the web-link under External Links below) and states that originally, all human beings were type O. However, based on results obtained using the modern genetic method, some evolutionary biologists theorize that the ''A'' allele evolved first, followed by ''O'' (''O'' being formed by the deletion of a single nucleotide, which shifts the reading frame), and then ''B''. This chronology accounts for the percentage of people worldwide with each blood type. This more recent theory is also consistent with accepted patterns of early population movements and varying prevalent blood types in different parts of the world. For instance, type B is very common in populations of Asian descent, but rare in ones of Western European descent. 

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

In the UK the distribution of blood type frequencies throughout the population still shows some correlation both to the distribution of [[Toponymy|placenames]] and to the successive invasions and migrations (including Vikings, Danes, Saxons, Celts, and Normans) that contributed the [[morphemes]] and [[genes]] to the population.<ref name=Potts_1979>{{cite book |last= Potts |first= WTW |authorlink= |coauthors= |editor= Sawyer PH |others= |title= English Medieval Settlement |origdate= |origyear= |origmonth= |edition= |date= |year= 1979 |month= |publisher= St. Martin's Press |location= |id= ISBN 0-7131-6257-0 |doi = |pages= |chapter= History and Blood Groups in the British Isles |}}</ref>

There are six common [[allele]]s that produce one's blood type:<ref>{{cite journal |author=Seltsam A, Hallensleben M, Kollmann A, Blasczyk R |title=The nature of diversity and diversification at the ABO locus |journal=Blood |volume=102 |issue=8 |pages=3035–42 |year=2003 |pmid=12829588 |doi=10.1182/blood-2003-03-0955}}</ref><ref>{{cite journal |author=Ogasawara K, Bannai M, Saitou N, ''et al'' |title=Extensive polymorphism of ABO blood group gene: three major lineages of the alleles for the common ABO phenotypes |journal=Hum. Genet. |volume=97 |issue=6 |pages=777–83 |year=1996 |pmid=8641696 |doi=}}</ref>
{{Multicol}}
;A
*ABO*A101 (A1) {{Gene|ABO}}
*ABO*A201 (A2)
{{Multicol-break}}
;B
*ABO*B101 (B1)
{{Multicol-break}}
;O
*ABO*O01 (O1)
*ABO*O02 (O1v)
*ABO*O03 (O2)
{{Multicol-end}}

Many rare variants of these alleles have been found in human populations around the world.

== Association with von Willebrand factor ==

The ABO antigen is also expressed on the [[von Willebrand factor]] (vWF) [[glycoprotein]],<ref>{{cite journal | last = Sarode | first = R | authorlink =   | coauthors = Goldstein J, Sussman II, Nagel RL, Tsai HM | title = Role of A and B blood group antigens in the expression of adhesive activity of von Willebrand factor | journal = Br J Haematol. | volume = 109 | issue = 4 | pages = 857-64 | publisher = | date = 2000 Jun | url = | doi = | id = PMID 10929042 | accessdate =  }}</ref> which participates in [[hemostasis]] (control of bleeding). In fact, having type O blood predisposes someone to bleeding,<ref>{{cite journal | last = O'Donnell | first = J | coauthors = Laffan MA | title = The relationship between ABO histo-blood group, factor VIII and von Willebrand factor | journal = Transfus Med. | volume = 11 | issue = 4 | pages = 343-51 | publisher = | date = 2001 Aug | url = | doi = 10.1046/j.1365-3148.2001.00315.x | id = PMID 11532189| accessdate =  }}</ref> as 30% of the total genetic variation observed in plasma vWF is explained by the effect of the ABO blood group,<ref>{{cite journal | last = O'Donnell | first = J | coauthors = Boulton FE, Manning RA, Laffan MA | title = Amount of H antigen expressed on circulating von Willebrand factor is modifiedby ABO blood group genotype and is a major determinant of plasma von Willebrand factor antigen levels | journal = Arterioscler Thromb Vasc Biol. | volume = 22 | issue = 2 | pages = 335-41 | publisher = American Heart Association, Inc. | date = 2002 Feb 1 | url = http://atvb.ahajournals.org/cgi/content/full/22/2/335 | doi = | id = PMID 11834538 | accessdate =  }}</ref> and individuals with group O blood normally have significantly lower plasma levels of vWF (and [[Factor VIII]]) than do non-O individuals.<ref>{{cite journal | last = Gill | first = JC | coauthors = Endres-Brooks J, Bauer PJ, Marks WJ, Montgomery RR | title = The effect of ABO blood group on the diagnosis of von Willebrand disease | journal = Blood | volume = 69 | issue = 6 | pages = 1691-5 | publisher = | date = 1987 Jun | url = http://www.bloodjournal.org/cgi/content/abstract/69/6/1691 | doi = | id = PMID 3495304 | accessdate =  }}</ref><ref>{{cite journal | last = Shima | first = M | coauthors = Fujimura Y, Nishiyama T et. al | title = ABO blood group genotype and plasma von Willebrand factor in normal individuals | journal = Vox Sang | volume = 68 | issue = 4 | pages = 236–40 | publisher = | date = 1995 | url = | doi = | id = PMID 7660643 | accessdate =  }}</ref> 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 (biology)|polymorphism]] in VWF):<ref>{{cite journal | last = Bowen | first = DJ | coauthors = Collins PW, Lester W, et. al | title = The prevalence of the cysteine1584 variant of von Willebrand factor is increased in type 1 von Willebrand disease: co-segregation with increased susceptibility to ADAMTS13 proteolysis but not clinical phenotype | journal = Br J Haematol | volume = 128 | issue = 6 | pages = 830-6 | publisher = Blackwell Synergy| date = 2005 Mar | url = | doi = 10.1111/j.1365-2141.2005.05375.x | id = PMID 15755288 | accessdate =  }}</ref> the gene for [[ADAMTS13]] (vWF-cleaving [[protease]]) maps to the [[Chromosome 9|ninth chromosome]] (9q34), the same [[Locus (genetics)|locus]] as ABO blood type. Higher levels of vWF are more common amongst people who have had an [[Stroke#Ischemic stroke|ischaemic stroke]] (from blood clotting) for the first time.<ref>{{cite journal | author = Bongers T, de Maat M, van Goor M, et. al | title = High von Willebrand factor levels increase the risk of first ischemic stroke: influence of ADAMTS13, inflammation, and genetic variability. | journal = Stroke | volume = 37 | issue = 11 | pages = 2672-7 | year = 2006 | id = PMID 16990571}}</ref> The results of this study found that occurrence was not affected by ADAMTS13 polymorphism, and the only significant genetic factor was the person's blood group.

== Bombay phenotype ==
{{main|Hh antigen system}}

Individuals with the rare Bombay phenotype (''[[Hh antigen system|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 the hh [[genotype]]) as well as to both A and B antigens, and can therefore receive blood only from other ''hh'' donors (although they can donate as though they were type O).

== Nomenclature in Europe and former USSR ==

In parts of Europe the "O" in ABO blood type is substituted with the numeral "0" (zero), signifying the lack of A or B antigens. In the former U.S.S.R blood types are referenced using numbers and Roman numerals instead of letters. This is [[Jan Jansky|Janský's]] original classification, which designates the blood types of humans as I, II, III, and IV, elsewhere designated, respectively, as O, A, B, and AB.<ref name=Erb_1940>{{cite journal | author = Erb IH | title = Blood Group Classifications, a Plea for Uniformity | journal = Canadian Medical Association Journal | year = 1940 | volume = 42 | issue = 5 | pages = 418–21 | url= http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=537907}}</ref> The designation of A and B with reference to blood groups was proposed by [[Ludwik Hirszfeld]].

== Examples of ABO and Rhesus D slide testing method ==

<gallery>
Image:RhO+.jpg|Blood group O positive: neither anti-A nor anti-B have agglutinated, but anti-Rh has
Image:RhB-.JPG|Result: Blood group B negative: anti-A and anti-Rh have not agglutinated but anti-B has
</gallery>

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

==Universal blood created from other types, and artificial blood==

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. <ref>{{cite journal
 | quotes = 
 | last = Liu
 | first = QP
 | authorlink = 
 | coauthors = Sulzenbacher G, Yuan H, Bennett EP, Pietz G, Saunders K, Spence J, Nudelman E, Levery SB, White T, Neveu JM, Lane WS, Bourne Y, Olsson ML, Henrissat B, Clausen H
 | date = 
 | year = 2007
 | month = Apr
 | title = Bacterial glycosidases for the production of universal red blood cells
 | journal = Nat Biotechnol
 | volume = 25
 | issue = 4
 | pages = 454-64
 | issn = 
 | pmid = 17401360
 | doi = 
 | id = 
 | url = http://www.nature.com/nbt/journal/v25/n4/abs/nbt1298.html
 | language = 
 | format = 
 | accessdate = 
 | laysummary = 
 | laysource = 
 | laydate = 
 | quote = 
 }}
</ref> This conversion is done by using [[Glycoside hydrolase|glycosidase]] enzymes from specific bacteria to strip the blood group antigens from [[red blood cell]]s. The removal of A and B antigens still does not address the problem of the [[Rhesus blood group system|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.

Another approach to the blood antigen problem is the creation of  [[artificial blood]], which could act as a substitute in emergencies. [http://news.bbc.co.uk/2/hi/uk_news/england/north_yorkshire/6645923.stm BBC].

==Myths==

There are numerous popular myths surrounding ABO blood groups.  These beliefs have existed since ABO blood groups were identified and can be found in different cultures throughout the world.  For example, during the 1930s, connecting [[Japanese blood type theory of personality|blood groups to personality types]] became popular in Japan and other areas of the world.<ref>{{cite journal
 | quotes = 
 | last = American Red Cross
 | first = Southern California Blood Services Region
 | authorlink = 
 | coauthors = 
 | date = 
 | year = n.d. 
 | month = 
 | title = Answers to Commonly Asked Questions About Blood and Blood Banking
 | journal = Blood: The Basics
 | volume = 
 | issue = 
 | pages = 4
 | issn = 
 | pmid = 
 | doi = 
 | id = 
 | url = http://www.socalredcross.org/pdf/BloodThe.pdf
 | language = 
 | format = electronic
 | accessdate = Nov 16 2007
 | laysummary = 
 | laysource = 
 | laydate = 
 | quote = 
 }}
</ref>

The popularity of [[Peter J. D'Adamo]]'s book, ''Eat Right For Your Blood Type'' suggests that these myths persist.  This book claims that ABO blood groups can be used to determine [[diet]] as well as to predict [[diseases]].  

Additional myths include the idea that Group A causes severe [[hangover]]s, group O is associated with perfect [[teeth]], and those with blood group A2 have the highest IQs.  Scientific evidence in support of these concepts is scant or nonexistent.<ref>{{cite journal
 | quotes = 
 | last = Klein
 | first = Harvey G
 | authorlink = 
 | coauthors = 
 | date = 7
 | year = 2005
 | month = Mar
 | title = Why Do People Have Different Blood Types?
 | journal = Scientific American
 | volume = 
 | issue = 
 | pages = 
 | issn = 
 | pmid = 
 | doi = 
 | id = 
 | url = http://www.sciam.com/biology/article/id/why-do-people-have-differ/catID/3
 | language = 
 | format = 
 | accessdate = Nov 16 2007
 | laysummary = 
 | laysource = 
 | laydate = 
 | quote = 
 }}
</ref>

== References ==
{{Reflist|2}}

== Further reading ==

* {{cite web | author = Dean L | title = Chapter 5: The ABO blood group. | work = Blood Groups and Red Cell Antigens | url = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=rbcantigen.chapter.ch05ABO |date = 2005 | accessdate = 2007-03-24}}

* {{cite journal |author=Farr A |title=Blood group serology--the first four decades (1900--1939) |journal=Med Hist |volume=23 |issue=2 |pages=215-26 |year=1979 |url = http://www.pubmedcentral.gov/articlerender.fcgi?artid=1082436 | pmid=381816}}

== External links ==

* [http://www.ncbi.nlm.nih.gov/projects/mhc/xslcgi.fcgi?cmd=bgmut/systems_info&system=abo ABO at BGMUT] Blood Group Antigen Gene Mutation Database at [[National Center for Biotechnology Information|NCBI]], [[NIH]]
* [http://health.hosuronline.com/BloodGroupingsTechniques.php Blood Grouping techniques]
* [http://www.britannica.com/eb/article-9003372/ABO-blood-group-system Encyclopaedia Britannica, ABO blood group system]
* [http://www.blood.co.uk/pages/world_blood.html National Blood Transfusion Service]
* [http://abobloodgroup.googlepages.com/ Molecular Genetic Basis of the Blood Group ABO system]

{{transfusion medicine}}


[[Category:Blood]]
[[Category:Blood antigen systems]]
[[Category:Hematology]]

[[da:AB0]]
[[de:AB0-System]]
[[dv:އޭބީއޯ ލޭގެ ގުރޫޕްގެ ނިޒާމް]]
[[et:AB0-süsteem]]
[[fr:Système ABO]]
[[gl:Sistema AB0]]
[[is:ABO-blóðflokkar]]
[[ja:ABO式血液型]]

{{WikiDoc Help Menu}}
{{WikiDoc Sources}}