Download ABO AND RH SYSTEM (Blood Grouping) • LEARNING OBJECTIVE

ABO AND RH SYSTEM
(Blood Grouping)
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LEARNING OBJECTIVE
At the end of this lecture ,the student should be able to:
Describe function of agglutinogen and agglutinin in relation to blood group
Describe antigen and antibody of ABO system
Describe mechanism that inherits the ABO system.
List phenotype and genotype of possible ABO types.
Describe antigen and antibody of Rh system.
Explain universal donor and universal recipient.
Describe transfusion reaction related to ABO and Rh system
Describe erythroblastosis foetalis.
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BLOOD GROUPS
Membrane of red blood cell contain blood group antigens- agglutinogens
Most important : ABO
Rh also important
Less important: MNSs, Lutheran, Kidd, Kell
ABO SYSTEM
4 major blood groups:
A-antigen A
B- antigen B
AB- antigen A & B
O- no antigen
Found in other tissue- kidney, liver, lungs
Prevalence:
O- 47%
A- 41%
B- 9%
AB- 3%
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BLOOD GROUPS
INHERITANCE OF ABO SYSTEM
• Inherited as mendelian allelomorphs
• Two genes- one on each of two paired chromosomes
• Phenotype B- Genotype BB
(homozygous) or BO (heterozygous)
• When blood type of parents known possible genotypes can be predicted
• Blood type of child matching with father is used for proving the parental father.
RH FACTOR
TRANSFUSION REACTION
• Cell antigen from donor will react with recipient antibody
• AB type- universal recipients
• 0 type- universal donors
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But always need cross match
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WHO CAN RECEIVE BLOOD FROM WHOM
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HEMOLYTIC DISEASE OF NEWBORN (HDN)
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ERYTHROBLASTOSIS FOETALIS
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A severe hemolytic disease of a fetus or newborn infant caused by the production of
maternal antibodies against the fetal red blood cells, usually involving Rh incompatibility
between the mother and fetus.
Causes
Common causes for HDN
Rh system antibodies
ABO system antibodies
Uncommon causes
Kell system antibodies
Rare causes
Duffy system antibodies
MNS and s system antibodies
No occurrence in HDN
Lewis system antibodies
P system antibodies
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Rh Incompatibility
Rh antigens exist in 3 loci: Cc, Dd, and Ee
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Expression is limited to RBCs
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Rh positive: 45% are homozygous and 55% are heterozygous
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Rh incompatibility is a condition which develops when there is a difference in Rh blood
type between that of the pregnant mother (Rh negative) and that of the fetus (Rh
positive).
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After the initial exposure to a foreign antigen, the maternal immune system produces
antibodies of the immunoglobulin M (IgM) isotype that do not cross the placenta, and
later it produces antibodies of the IgG isotype that traverse the placental barrier.
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BEFORE BIRTH
Antibodies cause destruction of the red cells
Anemia
heart failure
fetal death
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AFTER BIRTH
Antibodies cause destruction of the red cells
Anemia
Heart failure
Build up of bilirubin
Kernicterus
Severe retardation
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PROBLEMS FOR BABY
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Anemia
heart failure
erythroblastosis
General edema
Called hydrops fetalis and erythroblastosis fetalis
Kernicterus
severe retardation
REFERENCES
• Medical physiology
• Guyton & Hall
• 12th edition
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Medical physiology
Ganong
23rd edition
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