2ABO BLOOD GROUPHistoryLandsteiners discovered the ABO Blood Group System in 1901He and five co-workers began mixing each others red blood cells and serum together and accidentally performed the ABO groupings.Main Phenotypes (A, B, AB, O)ABO gene located on long arm of chromosome 9
3History of Blood Groups and Blood Transfusions (Cont.) Karl Landsteiner discovered that blood clumping was an immunological reaction which occurs when the receiver of a blood transfusion has antibodies against the donor blood cells.Karl Landsteiner's work made it possible to determine blood types and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930.
4Inheritance of ABO Groups Allele from the motherAllele from the fatherGenotype of offspringBlood types of offspringAAABABOAOBBBOOO
6Blood Transfusions Rh + Can receive + or - Rh - Can only receive - A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness.Rh + Can receive + or -Rh - Can only receive -
7Significance of ABO Group ABO mismatched transfusions:RareMay be life threateningCan be caused by technical or clerical errorIntravascular haemolysisMore severe in group O patients
8The Rh(D) Antigen RH is the most complex system, with over 45 antigens Discovered in 1940 after work on Rhesus monkeysSubsequently discovered to be unrelated to monkeysRH gene located on short arm of chromosome 1
9Rh antigens are transmembrane proteins with loops exposed at the surface of red blood cells. They appear to be used for the transport of carbon dioxide and/or ammonia across the plasma membrane.RBCs that are "Rh positive" express the antigen designated D.
10Simple Genetics of Rh(D) 86% of caucasians are Rh(D) posThe antithetical antigen d has not been foundThe d gene is recessive:Dd, dD, DD, persons are Rh(D) posOnly dd persons are Rh(D) neg
11Distribution of Rh(D) Types PopulationRh(D) posRh(D) negCaucasian86%14%African-American95%5%Oriental>99%<1%
12Significance of Rh(D)80% of Rh(D) neg persons exposed to Rh(D) pos blood will develop anti-DAnti-D can also be stimulated by pregnancy with an Rh(D) positive babySensitisation can be prevented by the use of anti-D immunoglobulin, antenatally and post natallyRh(D) neg females of childbearing potential should never be given Rh(D) positive blood products
13Inheritance of ABO and Rh(D) MotherGroup A AORh(D) pos DdFatherGroup B BORh(D) pos DdGroup A AORh(D) pos DdGroup B BORh(D) pos DdGroup O OORh(D) neg dd
14A person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies.A person with Rh+ blood can receive blood from a person with Rh- blood without any problems.
15Why is an Rh incompatibility so dangerous during pregnancy? Most anti-A or anti-B antibodies are of the IgM class (large molecules) and these do not cross the placenta.In fact, an Rh−/type O mother carrying an Rh+/type A, B, or AB foetus is resistant to sensitisation to the Rh antigen.Her anti-A and anti-B antibodies destroy any foetal cells that enter her blood before they can elicit anti-Rh antibodies in her.
16Rh incompatibility during pregnancy (cont.) This phenomenon has led to an effective preventive measure to avoid Rh sensitisation.Shortly after each birth of an Rh+ baby, the mother is given an injection of anti-Rh antibodies (or Rhogam).These passively acquired antibodies destroy any foetal cells that got into her circulation before they can elicit an active immune response in her.
17The ABO Antigens Added to Proteins or Lipids in Red Cells ABO & Rh(D)The ABO AntigensAdded to Proteins or Lipids in Red CellsSubstrate Molecule is H (fucose)A antigen is N-acetyl-galactosamine (GalNAc)B antigen is Galactose (Gal)A and B genes code for transferase enzymes
18H antigenThe H antigen is the foundation upon which A and B antigens are builtA and B genes code for enzymes that add an immunodominant sugar to the H antigenImmunodominant sugars are present at the terminal ends of the chains and confer the ABO antigen specificity
19Formation of the H antigen RBCGlucoseH antigenGalactoseH enzyme is fucosyltransferaseN-acetylglucosamineGalactoseFucose
20A and B AntigenThe “A” gene codes for an enzyme (transferase) that adds N-acetylgalactosamine to the terminal sugar of the H antigenN-acetylgalactosaminyltransferaseThe “B” gene codes for an enzyme that adds D-galactose to the terminal sugar of the H antigenD-galactosyltransferase
21Formation of the A antigen RBCGlucoseGalactoseN-acetylglucosamineGalactoseN-acetylgalactosamineFucose
22Formation of the B antigen RBCGlucoseGalactoseN-acetylglucosamineGalactoseGalactoseFucose
23GeneticsThe H antigen is found on the RBC when you have the Hh or HH genotype, but NOT from the hh genotypeThe A antigen is found on the RBC when you have the Hh, HH, and A/A, A/O, or A/B genotypesThe B antigen is found on the RBC when you have the Hh, HH, and B/B, B/O, or A/B genotypes
24Blood Group O people have red blood cells rich in H antigen. Why? Neither the A or B genes have converted the H antigens to A or B antigens - just a whole bunch of H!O allele at the ABO locus (amorph) It does not alter the structure of H substance.
25N acetylgalactosaminyl Donor Nucleotides & Immundominant Sugars responsible for H, A, and B Ags specificityAntigenImmunodominant sugarNucleotideGlcosyltransferaseGeneHL-fucoseGuanosineGDP-FUCL- fucosyl trnsferasAN-acetyl-D-galactoseamineUridineUDP-GALNACN acetylgalactosaminyltransferaseBD-galactoseUDP-GALD- galactosyl transferase
26ABO Antigens in Secretions Secretions include body fluids like plasma, saliva, synovial fluid, etcBlood Group Substances are soluble antigens (A, B, and H) that can be found in the secretions. This is controlled by the H and Se genes
27Secretor Status The secretor gene consists of 2 alleles (Se and se) The Se gene is responsible for the expression of the H antigen on glycoprotein structures located in body secretionsIf the Se allele is inherited as SeSe or Sese, the person is called a “secretor”80% of the population are secretors
28SecretorsSecretors express soluble forms of the H antigen in secretions that can then be converted to A or B antigens (by the transferases)Individuals who inherit the sese gene are called “nonsecretors”Secretions include saliva, urine, tears, bile, amniotic fluid, breast milk, exudate, and digestive fluids.
29Lewis (Le)The Lewis Blood Group System is mentioned here because it is related to secretor statusLewis antigens are plasma antigens formed by tissues and are released into plasma where they adsorb onto the RBCsConsists of 2 antigensLeaLeb
30ABO SubgroupsABO subgroups differ in the amount of antigen present on the red blood cell membraneSubgroups have less antigenSubgroups are the result of less effective enzymes. They are not as efficient in converting H antigens to A or B antigens (fewer antigens are present on the RBC)Subgroups of A are more common than subgroups of B
31Subgroups of A The 2 principle subgroups of A are: A1 and A2 Both react strongly with reagent anti-ATo distinguish A1 from A2 red cells, the lectin Dolichos biflorus is used (anti-A1)80% of group A or AB individuals are subgroup A120% are A2 and A2B
32B Subgroups B subgroups occur less than A subgroups B subgroups are differentiated by the type of reaction with anti-B, anti-A,B, and anti-HB3, Bx, Bm, and Bel
33Other ABO conditions Bombay Phenotype (Oh) Inheritance of hh The h gene is an amorph and results in little or no production of L-fucosyltransferaseOriginally found in Bombay (now Mumbai)Very rare (130 worldwide)
34ABO antibodies group A serum contains anti-B group B serum contains anti-Agroup AB serum contains no antibodiesgroup O serum contains anti-A, anti-B, and anti-A,B
35Anti-A1 Group O and B individuals contain anti-A in their serum However, the anti-A can be separated into different components: anti-A and anti-A1Anti-A1 only agglutinates the A1 antigen, not the A2 antigenThere is no anti-A2.
36Anti-A,B Found in the serum of group O individuals Reacts with A, B, and AB cellsPredominately IgG, with small portions being IgMAnti-A,B is one antibody, it is not a mixture of anti-A and anti-B antibodies
37ABO antibodiesIgM is the predominant antibody in Group A and Group B individualsAnti-AAnti-BIgG (with some IgM) is the predominant antibody in Group O individualsAnti-A,B (with some anti-A and anti-B)
38ABO Antibodies Usually present within the first 3-6 months of life Stable by ages 5-6 yearsDecline in older ageNewborns may passively acquire maternal antibodies (IgG crosses placenta)Remember: most ABO antibodies are IgM, but some are IgG. Mothers can pass those IgG antibodies through placenta to fetus
40ABO Blood Groups ABO Group Antigen Present Antigen Missing Antibody PresentABanti-Banti-AONoneA and Banti-A, anti-B, anti-A,BAB
41The ABO Blood Group System Laboratory Determination of the ABO System
42Serology: This is a direct detection of the ABO antigens Serology: This is a direct detection of the ABO antigens. It is the main method used in blood transfusion centres and hospital blood banks.This form of testing involves two components:a) Antibodies that are specific at detecting a particular ABO antigen on RBCs. b) Cells that are of a known ABO group that are agglutinated by the naturally occurring antibodies in the person's serum.
43Illustration of the forward and reverse grouping reaction patterns of the ABO groups using a blood group tile
44RESOURCESAldahr MHS. ABO Blood Group. Faculty of Applied Medical Sciences Blood Bank Medical Tecnology. download 2011Giacobbe. ABO & Rh(D) Blood Groups. Anatomy & Physiology. Unit 9 – Circulatory System.download 2011Musani MI. Blood groups and Rhesus factor. Download 2011Trimpe T. Blood Basics. Forensic Science.2006Wilkins RN. ABO Blood Group System. University of Mississippi Medical Center. Download 2011.