1. Blood Group
dr. Husnil Kadri, M.Kes

2. ABO BLOOD GROUP
History
Landsteiners discovered the ABO Blood Group System in 1901
He 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

3. History 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.

4. Inheritance of ABO Groups
Allele from the mother
Allele from the father
Genotype of offspring
Blood types of offspring A AA B AB O AO BB BO OO

6. Blood 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 -

7. Significance of ABO Group
ABO mismatched transfusions:
Rare
May be life threatening
Can be caused by technical or clerical error
Intravascular haemolysis
More severe in group O patients

8. The Rh(D) Antigen RH is the most complex system, with over 45 antigens
Discovered in 1940 after work on Rhesus monkeys
Subsequently discovered to be unrelated to monkeys
RH gene located on short arm of chromosome 1

9. Rh 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.

10. Simple Genetics of Rh(D)
86% of caucasians are Rh(D) pos
The antithetical antigen d has not been found
The d gene is recessive:
Dd, dD, DD, persons are Rh(D) pos
Only dd persons are Rh(D) neg

11. Distribution of Rh(D) Types
Population
Rh(D) pos
Rh(D) neg
Caucasian
86%
14%
African-American
95% 5%
Oriental
>99%
<1%

12. Significance of Rh(D)
80% of Rh(D) neg persons exposed to Rh(D) pos blood will develop anti-D
Anti-D can also be stimulated by pregnancy with an Rh(D) positive baby
Sensitisation can be prevented by the use of anti-D immunoglobulin, antenatally and post natally
Rh(D) neg females of childbearing potential should never be given Rh(D) positive blood products

13. Inheritance of ABO and Rh(D)
Mother
Group A AO
Rh(D) pos Dd
Father
Group B BO
Rh(D) pos Dd
Group A AO
Rh(D) pos Dd
Group B BO
Rh(D) pos Dd
Group O OO
Rh(D) neg dd

14.                                                                            
A 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.

15. Why 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.

16. Rh 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.

17. The ABO Antigens Added to Proteins or Lipids in Red Cells
ABO & Rh(D)
The ABO Antigens
Added to Proteins or Lipids in Red Cells
Substrate Molecule is H (fucose)
A antigen is N-acetyl-galactosamine (GalNAc)
B antigen is Galactose (Gal)
A and B genes code for transferase enzymes

18. H antigen
The H antigen is the foundation upon which A and B antigens are built
A and B genes code for enzymes that add an immunodominant sugar to the H antigen
Immunodominant sugars are present at the terminal ends of the chains and confer the ABO antigen specificity

19. Formation of the H antigen
RBC
Glucose
H antigen
Galactose
H enzyme is fucosyltransferase
N-acetylglucosamine
Galactose
Fucose

20. A and B Antigen
The “A” gene codes for an enzyme (transferase) that adds N-acetylgalactosamine to the terminal sugar of the H antigen
N-acetylgalactosaminyltransferase
The “B” gene codes for an enzyme that adds D-galactose to the terminal sugar of the H antigen
D-galactosyltransferase

21. Formation of the A antigen
RBC
Glucose
Galactose
N-acetylglucosamine
Galactose
N-acetylgalactosamine
Fucose

22. Formation of the B antigen
RBC
Glucose
Galactose
N-acetylglucosamine
Galactose
Galactose
Fucose

23. Genetics
The H antigen is found on the RBC when you have the Hh or HH genotype, but NOT from the hh genotype
The A antigen is found on the RBC when you have the Hh, HH, and A/A, A/O, or A/B genotypes
The B antigen is found on the RBC when you have the Hh, HH, and B/B, B/O, or A/B genotypes

24. Blood 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.

25. N acetylgalactosaminyl
Donor Nucleotides & Immundominant Sugars responsible for H, A, and B Ags specificity
Antigen
Immunodominant sugar
Nucleotide
Glcosyltransferase
Gene H
L-fucose
Guanosine
GDP-FUC
L- fucosyl trnsferas A
N-acetyl-D-galactoseamine
Uridine
UDP-GALNAC
N acetylgalactosaminyl
transferase B
D-galactose
UDP-GAL
D- galactosyl transferase

26. ABO Antigens in Secretions
Secretions include body fluids like plasma, saliva, synovial fluid, etc
Blood 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

27. Secretor 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 secretions
If the Se allele is inherited as SeSe or Sese, the person is called a “secretor”
80% of the population are secretors

28. Secretors
Secretors 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.

29. Lewis (Le)
The Lewis Blood Group System is mentioned here because it is related to secretor status
Lewis antigens are plasma antigens formed by tissues and are released into plasma where they adsorb onto the RBCs
Consists of 2 antigens
Lea
Leb

30. ABO Subgroups
ABO subgroups differ in the amount of antigen present on the red blood cell membrane
Subgroups have less antigen
Subgroups 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

31. Subgroups of A The 2 principle subgroups of A are: A1 and A2
Both react strongly with reagent anti-A
To distinguish A1 from A2 red cells, the lectin Dolichos biflorus is used (anti-A1)
80% of group A or AB individuals are subgroup A1
20% are A2 and A2B

32. B 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-H
B3, Bx, Bm, and Bel

33. Other ABO conditions Bombay Phenotype (Oh) Inheritance of hh
The h gene is an amorph and results in little or no production of L-fucosyltransferase
Originally found in Bombay (now Mumbai)
Very rare (130 worldwide)

34. ABO antibodies group A serum contains anti-B
group B serum contains anti-A
group AB serum contains no antibodies
group O serum contains anti-A, anti-B, and anti-A,B

35. Anti-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-A1
Anti-A1 only agglutinates the A1 antigen, not the A2 antigen
There is no anti-A2.

36. Anti-A,B Found in the serum of group O individuals
Reacts with A, B, and AB cells
Predominately IgG, with small portions being IgM
Anti-A,B is one antibody, it is not a mixture of anti-A and anti-B antibodies

37. ABO antibodies
IgM is the predominant antibody in Group A and Group B individuals
Anti-A
Anti-B
IgG (with some IgM) is the predominant antibody in Group O individuals
Anti-A,B (with some anti-A and anti-B)

38. ABO Antibodies Usually present within the first 3-6 months of life
Stable by ages 5-6 years
Decline in older age
Newborns 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

39. Laboratory Testing:
ABO typing

40. ABO Blood Groups ABO Group Antigen Present Antigen Missing
Antibody Present A B
anti-B
anti-A O
None
A and B
anti-A, anti-B, anti-A,B AB

41. The ABO Blood Group System
                                                                                                                            Laboratory  Determination of the ABO System                                                                       

42. Serology: 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.

43. Illustration of the forward and reverse grouping reaction patterns of the ABO groups using a blood group tile

44. RESOURCES
Aldahr MHS. ABO Blood Group. Faculty of Applied Medical Sciences Blood Bank Medical Tecnology. download 2011
Giacobbe. ABO & Rh(D) Blood Groups. Anatomy & Physiology. Unit 9 – Circulatory System.download 2011
Musani MI. Blood groups and Rhesus factor. Download 2011
Trimpe T. Blood Basics. Forensic Science.2006
Wilkins RN. ABO Blood Group System. University of Mississippi Medical Center. Download 2011.