BLOOD GROUPS

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• BLOOD GROUPS
• Blood types

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• Objectives
• 1. List the various types of blood groups.
• 2. Understand that the RBC surface antigens A or
  B, or their absence
• is responsible for determining the
  blood groups as A, B AB or O,
• and that these are genetically
  determined..
• 3. Understand that the plasma contains antibodies
  of the same name
• 4. Explain why a person having a particular blood
  group (for example
• group A) can not have antibody of the
  same type in the plasma.
• 5. Compare the distribution of blood groups in
  the Omani population
• with some other populations
• 6. Describe the importance of the Rhesus blood
  group, and
• understand that humans are also
  classified as Rhve or Rh ve,
• and that about 95 of Omanis are Rh ve.
• 7. Define the term Rh incompatibility and
  understand that fetal RBC
• get hemolysed in this condition.
• 8. Define the term Mismatched transfusion.

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• antigens on RBC blood group antibody in
  plasma
• A Type A
  B
• B Type B
  A
• A B Type AB
  nil
• O (nil) Type O
  AB

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Genetic determination of blood groups

• Antigens are genetically determined
• Each gene carries
• either NO antigen (O)
• Antigen A
• Antigen B
• Paired genes (one from each parent when
  they meet will have
• i. No antigen antigen A Genotype
  (OA) Blood group A
• ii. No antigen antigen B Genotype (OB)
  Blood group B
• iii. No antigen No antigen Genotype (OO)
  Blood group O
• iv. Antigen A antigen B Genotype (AB)
  Blood group AB
• v. Antigen A antigen A Genotype (AA)
  Blood group A
• vi. Antigen B antigen B Genotype (BB)
  Blood group B

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• Antibodies not present at birth.
• 2. Develop when small amts of antigens A B
  enter body as food, in bacteria etc
• Host develops antibodies to these.
• 4. Chemically these are Ig G and Ig M
  imunoglobulins

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distribution of Blood groups in Omani other
populations
A B AB O Rhve
OMANI 30 20 5 45 95
White Americans 40 11 4 45 85
Indian 21 39 9 31 95
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• Blood transfusion
• 1. Typing blood groups of donor and recipient
• Type A cannot be given to B and vice
  versa
• Type O is universal donor no antigen on
  RBC so no reaction
• Type AB universal recipient no
  antibodies
• blood

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Type A group (recipient) Antigen A antibody B
Type B group (donor) Antigen B antibody A

antibody B of recipient will react with antigen B
of donor (agglutination) and cause
hemolyis of donor cells
but Anti A of donor get too diluted to
affect A type cells of Recipient. So recipient
cells not affected significantly

• Clinical presentation of mismatched transfusion
• Donor RBCs affected
• Immediate hemolysis chills rigors, acute renal
  failure shock
• Delayed hemolysis jaundice as macrophages digest
  the agglutinated
• RBCs

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To avoid this mismatch Blood grouping and
typing is done 1. Drop of recipient blood and
donor blood separately mixed with a drop of anti
A and anti B 2. Observe for agglutination and
confirm group type Then select donor type.
Suppose A is selected as donor for recipient
who is type A Cross matching is to be
done Donor RBCs recipients serum to ensure
that some other antibodies are not present in
recipient blood
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Blood Grouping and typing
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• Rh blood group (from Rhesus monkey)
• Those with antigen on RBC Rhve
• 90-95 population is Rh ve
• No anti Rh antibodies in plasma
• Those WITHOUT this antigen Rh ve.
• No antibodies in plasma
• (no spontaneous development of anti
  Rh)
• Rh -ve given Rh ve blood antibodies develop
• Next transfusion of Rh ve to the same person
  anti-bodies destroy RBCs

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• Hemolytic disease of the new born
• Mother Rh ve Father Rh ve
• Fetus Rh ve
• Some mixing of mother
• and fetal blood at delivery
• Mother develops anti-body
• to Rh antigen of fetus
• Next pregnanacy antibody from mother
• passes palental barrier and affects RBC of
  fetus

Hemolytic disease of the new born .Varied
severity from mild hemolysis to death
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• Uncommon blood groups
• M, N, Duffy
• Bombay Blood
• Useful for genetic testing in Forensic Medicine
• Usually titre too low to cause any problems

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• Summary
• Types of blood groups
• Source of antigens and antibodies
• Blood groups of Omani population vis-à-vis others
• Blood grouping qnd crossmatching
• Effects of mismatched transfusions
• Rh blood group and hemolytic disease of the new
  born