Blood Group Polymorphism

1. Blood Groups and Blood transfusion Physiology
By – Dr. Wahid

2. ▪ABO and Rh systems and their clinical significance.
▪Incompatibilities in Rh systems
▪Blood transfusions - basis of blood typing, Cross matching
▪Complications of Blood transfusions (transfusion reactions)

3. ABO blood group system
▫First ever blood transfusion was made dog to dog by British physician
Richard Lower in 1665.
▫Austrian immunologist Karl Landsteiner discovered the ABO blood group
System in 1901. In 1910 he won Nobel prize for medicine for this discovery.
In 1940- Karl Landsteiner and Alexander S Wiener reported another Rh blood
group.

4. Importance of knowing about blood group system
1. Safe blood transfusion that may be life saving.
2. To prevent hemolytic disease of new born (Rh compatibility in newborn)
3. To solve the legal disputes related to parenting claimant.
4. To study the Mendelian laws of genetics.

5. ABO blood group system
The ABO blood group antigens are complex
oligosaccharide chains that differ in their terminal sugar
and project above the RBC surface.
following types of abs may develop-
type A: anti-B abs, type B: anti-A abs, type O : both & type
AB: neither.

6. Landsteiner’s Law
1. If a certain agglutinogen is present on the surface of RBCs, the
corresponding agglutinin must be absent in the plasma.
2. If a certain agglutinogen is absent on the surface of RBCs, then
corresponding agglutinin must be present in the plasma.

7. ABO blood types Relative frequency of different blood types:
• O 47% • A 41% • B 09% • AB 3% (World)
ABO blood group system- Relative frequency

8. Inheritance of ABO blood group system
▪The ABO locus has three main allele forms: A, B, & O.
The A and B genes found on chromosome 9 and are
inherited one gene (allele) from father and one from
mother.
1.Homozygous A 2. Heterozygous A
Genotype A/A Genotype A/0
Phenotype A Phenotype A

9. Blood Group Antigen Antibody Can donate
to
Can
receive
A A Anti-b A A
B B Anti-A B B
AB Ab None AB A, B, AB O.
O none AB A, B, AB O. 0
The antigen of the donor and the antibody of recipient is considered at the time of transfusion.

10. Universal Donor and Recipient / ABO blood group
Universal Donor : O-ve and
Universal Recipient AB+ve

11. Blood group Genotype
A AA, AO
B BB, O
AB AB
O OO

12. ▪The Rh factor, named for the rhesus monkey because it was first studied using the blood of this animal.
▪85% of whites are D-positive & 15% are D-negative; over 99% of Asians are D-positive.
▪ Antibodies to Rh antigens can be involved in hemolytic transfusion reactions and antibodies to
the Rh(D) and Rh antigens confer significant risk of hemolytic disease of the fetus and newborn.
Rh blood group system

13. It contains proteins on the surface of red blood cells. After the ABO blood group
system, it is the most likely to be involved in transfusion reactions.
The Rh blood group system consists of 49 defined blood group antigens,among
which the five antigens D, C, c, E, and e are the most important. There is no d
antigen.
Rh(D) status of an individual is normally described with a positive (+) or negative (–)
suffix after the ABO type (e.g., someone who is A+ has the A antigen and Rh(D)
antigen, whereas someone who is A– has the A antigen but lacks the Rh(D) antigen).
The terms Rh factor, Rh positive, and Rh negative refer to the Rh(D) antigen only.

14. The hemolytic condition occurs when there is an incompatibility between the blood
types of the mother and fetus. There is also potential incompatibility if the mother
is Rh negative and the father is positive.
When any incompatibility is detected, the mother often receives an injection at 28
weeks gestation and at birth to avoid the development of antibodies towards the
fetus.
The disorder in the fetus due to Rh D incompatibility is known as erythroblastosis
fetalis.
•Hemolytic comes from two words: "hema" (blood) and "lysis" (solution) or
breaking down of red blood cells
•Erythroblastosis refers to the making of immature red blood cells
•Fetalis refers to the fetus.
Erythroblastosis fetalis.

15. Prevention
When the condition is caused by the Rh D antigen-antibody incompatibility, it is called Rh D Hemolytic
disease of the newborn or Rh disease. Here, sensitization to Rh D antigens (usually by feto-maternal
transfusion during pregnancy) may lead to the production of maternal IgG anti-D antibodies which can pass
through the placenta
This is of particular importance to D negative females at or below childbearing age, because any subsequent
pregnancy may be affected by the Rh D hemolytic disease of the newborn if the baby is D positive. The vast
majority of Rh disease is preventable in modern antenatal care by injections of IgG anti-D antibodies (Rho(D)
Immune Globulin).
The incidence of Rh disease is mathematically related to the frequency of D negative individuals in a
population, so Rh disease is rare in old-stock populations of Africa and the eastern half of Asia, and the
Indigenous peoples of Oceania and the Americas, but more common in other genetic groups, most
especially Western Europeans, but also other West Eurasians, and to a lesser degree, native Siberians, as well
as those of mixed-race with a significant or dominant descent from those (e.g. the vast majority of Latin
Americans and Central Asians).

16. other's Rh factor Father's Rh factor Baby's Rh factor Precautions
Rh positive Rh positive Rh positive None
Rh negative Rh negative Rh negative None
Rh positive Rh negative Could be Rh positive
or Rh negative
None
Rh negative Rh positive Could be Rh positive
or Rh negative
Rh immune globulin
injections

17. Hemolytic disease of the newborn (Erythroblastosis Fetalis)
1. Hydrops fetalis-baby
may die in utero.
3. If mother has received
anti D abs injection at
time of Ist delivery, this
causes neutralization of
baby’s Rh+ve RBCs, and
immune system does not
activate to produce abs.
2. Erythroblastosis fetalis

18. Symptoms and signs in the newborn:
• Anemia that creates the newborn's pallor (pale
appearance).
• Jaundice or yellow discoloration of the newborn's skin,
sclera or mucous membrane. This may be evident right
after birth or after 24–48 hours after birth. This is caused
by bilirubin (one of the end products of red blood cell
destruction).
• Enlargement of the newborn's liver and spleen.
• The newborn may have severe edema of the entire body.
• Dyspnea (difficulty breathing)

19. MNSs blood group system, classification of human blood based on
the presence of various substances known as M, N, S, and s antigens
on the surfaces of red blood cells. This system, first discovered in
1927, has many distinct phenotypes and is of interest in genetic and
anthropological studies of human populations.

20. There are more than 40 antigens in the MNSs blood group system. The system
consists of two pairs of codominant alleles, designated M and N (identified in
1927) and S and s (identified 1947 and 1951, respectively). The alleles M and N
are usually distributed in populations in approximately equal frequencies.
However, the S and s alleles have varying frequencies, with the S allele
occurring in about 55 percent of whites and 30 percent of blacks, and the s
allele occurring in roughly 90 percent of individuals in both populations.
Antibodies to the M and N antigens rarely cause incompatibility reactions.
However, antibodies to S, s, and several can cause transfusion reactions and
erythroblastosis fetalis

21. Thank you