Blood groups are determined by the presence or absence of antigens on red blood cells. The two major blood group systems are ABO and Rh. In the ABO system, people are type O, A, B, or AB depending on whether they have the A and/or B antigens. Agglutinins against antigens not present develop in the plasma. Mismatched blood transfusions can cause immediate or delayed hemolytic transfusion reactions. The Rh system involves D antigens; an Rh negative person can form antibodies against Rh positive blood. This can cause erythroblastosis fetalis if the mother is sensitized during pregnancy with an Rh positive baby. Proper blood typing and matching is essential before transfusion to prevent dangerous transfusion reactions.

1. Blood groups
Dr. Sai Sailesh Kumar G
Associate Professor
Department of Physiology
RDGMC
DR Sai Sailesh Kumar G 1

2. Learning objectives
 Classify blood groups
 Define Landsteiner's law
 Describe Rh incompatibility
 Erythroblastosis fetalis,
 List indications of blood transfusion
 Describe the different transfusion reactions
 Describe the method of collection of blood,
storage, changes occurs in blood during storage
DR Sai Sailesh Kumar G 2

3. Introduction
 Antigens are present on the surface of red blood
cells
 30 commonly occurring antigens
 Hundreds of rare antigens were identified
 Two particular type of antigens are important
1. O-A-B system
2. Rh system
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4. O-A-B Blood Types
 Two important antigens- type A and type B
 They are also called agglutinogens
 They cause blood cell agglutination –
transfusion reactions
 Major blood groups
1. O – 47%
2. A – 41%
3. B – 9%
4. AB – 3% DR Sai Sailesh Kumar G 4

5. O-A-B Blood Types
 Classification based on the presence or absence
of the antigens A & B
 Neither A nor B present – O group
 Only type A present – A group
 Only type B present – B group
 Both A & B present – type AB
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6. First human blood transfusion
1667
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7. Human blood transfusion
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8. Karl landsteiner- 1930 Nobel Prize for Physiology or
Medicine for his discovery of the major blood groups
and the development of the ABO system
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9. Landsteiner’s laws
 The relationship between the agglutionogens on
RBC cells and agglutinins in the plasma is
reciprocal
1. First law: if an agglutinogen is present on the
RBC, corresponding agglutinin must be absent
in the plasma
2. Second law: if an agglutinogen is absent on the
RBC, corresponding agglutinin must be present
in the plasma DR Sai Sailesh Kumar G 9

10. Genetic determination of agglutinogens
 An allele is a variant form of a gene
 ABO blood group genetic locus has three alleles
 It means three different forms of same gene
 We typically call these alleles as A, B, O
 Type O allele is function less – does not cause
significant agglutination
 Type A & B – cause strong agglutination
 Type O is recessive to both type A & B
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11. Genetic determination of agglutinogens
 Each person has two sets of chromosomes
 Only one of these alleles is present on each of
the chromosomes
 It means three different forms of same gene
 Six possible combinations
 OO, OA, OB, AA, BB, AB
 These combination of alleles is called genotypes
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12. DR Sai Sailesh Kumar G 12

13. Genetic determination of agglutinogens
 Genotype OO produce no agglutinogens – blood
type is O
 Genotype OA or AA produce “A” agglutinogens
– Blood group is A
 Genotype OB or BB produce “B” agglutinogens
– Blood group is B
 Genotype AB produce both “A” and “B”
agglutinogens – Blood group is AB
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14. Agglutinins
 When type A agglutinogen is not present in
person’s RBC, antibodies known as anti A
agglutinogens develop in the plasma
 When type B agglutinogen is not present in
person’s RBC, antibodies known as anti B
agglutinogens develop in the plasma
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15. Agglutinins
 Immediately after birth – quantity of agglutinins
in plasma is almost zero
 2-8 months after birth, an infant begins to
produce antibodies
 At 8-10 years of age, maximum antibody titer
develops
 Gradually decline through out the remaining
years of life
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16. Origin of Agglutinins
 Agglutinins are gamma globulins
 Produced in bone marrow and lymphoid tissues
 Most of them are IgG and IgM molecules
 Why these antibodies produces in the person
who do not have respected agglutinogens?
 Small amounts of agglutinogens A and B enters
the body via food, some bacteria and initiate
development of agglutinins
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17. Agglutination
 When there is mismatched transfusion
 Anti A plasma mixed with red cells that contain A
agglutinogen
 Agglutinins attach to the RBC
 Agglutinins has 2 binding sites (IgG) and 10 biding
sites (IgM) respectively
 Single agglutinin can attach more than one RBC at a
time
 Clumping of the cells
 Agglutination DR Sai Sailesh Kumar G 17

18. Agglutination
 Agglutinated cells undergoes hemolysis
 Agglutinins activates the complement system
 Release of lytic enzymes
 Rupture RBC cell membrane
 Hemolysis of RBC
 Release of hemoglobin
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19. Blood typing
 Before blood transfusion it is must to determine
1. Blood type of recipient blood
2. Blood type of the donor
3. Matching of the blood
 This is called blood typing/ matching
 Red cells are separated from plasma
 Diluted with saline solution
 Mixed with agglutinins anti A and anti B
 Observe agglutination occurs or not
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20. Blood typing
 Type O has no agllutinogens so they do not form
agglutination with both A and B
 Type A has “A” agglutinogen so it form
agglutination with anti-A agglutinin
 Type B has “B” agglutinogen so it form
agglutination with anti-B agglutinin
 Type AB has “A & B” agglutinogens so it form
agglutination with anti-A and anti-B agglutinins
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21. DR Sai Sailesh Kumar G 21
Blood typing

22. Rh blood types
 Rh blood type system also important when
transfusing the blood
 In O-A-B system, the plasma agglutinins
responsible for causing transfusion reactions
develop spontaneously
 In Rh system, spontaneous agglutinins almost
never occur
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23. Rh positive & negative people
 Six common types of Rh antigens
 These types are C,D,E, c,d,e
 A person who has “C” antigen, does not have the
“c” antigen
 A person missing “C” antigen have “c” antigen
 The same is true for D-d and E-e antigens
 Each person has one of three pairs of antigens
 Type D antigen is most prevalent
 Person with D antigen- Rh positive
 Person with out type D antigen – Rh negative
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24. Rh immune response
 When Rh positive blood infused to Rh negative
person
 Anti Rh- agglutinins develops slowly
 Maximum concentration reached 2-4 months
later
 Multiple exposure to Rh antigens, an negative
person eventually become strongly sensitized to
Rh antigen
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25. Rh transfusion reactions
 When Rh positive blood infused to Rh negative person
for the first time
 No immediate reaction occurs
 Anti Rh-antibodies develops in 2-4 weeks
 Agglutination of transfused cells
 Hemolysis of cells by tissue macrophages
 Delayed transfusion reactions – mild
 Second time if Rh negative person is transfused with Rh
positive blood
 Immediate and severe transfusion reaction occurs as he
is already immunized against Rh positive antigen
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26. Erythroblastosis fetalis
 Hemolytic disease of new born
 Rh negative pregnant women
 Rh positive father
 Rh positive baby in her womb
 Rh incompatibility occurs
 Disease of fetus and new born child
 Characterized by agglutination and hemolysis of fetus RBC
 Mother develops anti-Rh antibodies after exposure to fetus Rh
antigens
 These agglutinins cross the placenta and enters fetus –
agglutination of RBC
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27. Erythroblastosis fetalis
 First child usually not affected
 Sensitization to Rh antigen occurs during
parturition of first child
 If mother underwent Rh positive blood
transfusion earlier
 First child also affected
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28. Incidence of the disease
 First child usually not affected
 3% of second Rh positive babies exhibit some
signs
 10% of third Rh positive babies exhibit the
disease
 Incidence raises progressively with subsequent
pregnancies
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29. Effect of mothers antibodies on fetus
 Anti Rh-antibodies formed in mother
 Diffuse slowly through placental membrane and
enters the fetus blood
 Agglutination of RBC
 Hemolysis
 Release of hemoglobin into blood
 Formation of bilirubin
 Baby skin become yellow (jaundiced)
 Antibodies can also attack and damage other cells
of the body
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30. Clinical picture
 Jaundiced, erythroblastic new born is anemic at birth
 Rh antibodies from mother keep circulation in the baby
blood for 1-2 months after birth
 Destroying more and more RBC
 Hemopoietic tissues tries to replace the hemolyzed cells
 Rapid production of red blood cells
 Many nucleated cells appear in the circulation – blast
cells
 That is why this disease called erythroblastosis fetalis
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31. Clinical picture
 Jaundiced, erythroblastic new born is anemic at
birth
 Usually child die due to severe anemia
 Who barely survive anemia exhibit permanent
mental impairment or damage of motor areas of
brain
 Because of precipitation of bilirubin in the neuronal
cells
 Destruction of neuronal cells
 kernicterus DR Sai Sailesh Kumar G 31

32. Treatment of neonates
 Exchange blood transfusion
 Replace neonates blood with Rh negative blood
 About 400 ml of Rh negative blood is infused over a period of
1.5 or more hours while neonates own Rh positive blood is
removed
 Process repeated several times during first few weeks of life
 Mainly to keep bilirubin levels low
 To prevent kernicterus
 By the time transfused Rh negative blood replaced by neonate
own Rh positive blood (6 or more weeks) , the antibodies from
mother are destroyed
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33. Prevention of erythroblastosis fetalis
 Anti-D antibody is administered to the expectant
mother starting at 28-30 weeks of gestation
 Anti-D antibody is also administered to the Rh
negative mother soon after delivery to prevent
sensitization
 Anti-d antibodies inhibits antigen induced B
lymphocyte antibody production in the mother
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34. Mismatched blood transfusion
 Mismatched blood transfusion
 RBC in the donar blood are agglutinated
 Immediate hemolysis by hemolysins
 Late hemolysis from phagocytosis of agglutinated
cells
 Transfusion reaction may be hemolytic or non
hemolytic
 In hemolytic reaction – hemoglobin released –
formation of bilirubin- excreted in bile
 May cause jaundice DR Sai Sailesh Kumar G 34

35. Mismatched blood transfusion
 Jaundice
 Yellowish discoloration of skin and sclera of
eyes
 However, if liver functioning normally
 Jaundice usually does not appears in an adult
unless more than 400 ml of blood is hemolyzed
in less than a day
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36. Type Cause Clinical features
HEMOLYTIC
Immediate ABO incompatibility Fever, chills, shock,
renal failure
Delayed Rh incompatibility Recurrent anemia, may
be fever
NONHEMOLYTIC
Febrile reaction Contamination of
stored blood with
endotoxin or due to
cytokines that are
released on storage
Fever and chills
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37. Renal failure after mismatched transfusion
 Most lethal effects of transfusion reactions
 Begins within few minutes to few hours and continue till
the person dies of acute renal failure
Causes
1. Powerful renal vasoconstriction by the toxic
substances released by the hemolyzing RBCS due to
agglutination
2. Decreased RBC – decreased blood – shock – decreased
renal blood flow – decreased urinary output
3. If increase in free hemoglobin in circulation, it leaks and
enters the renal tubules and precipitates – blocks renal
tubules DR Sai Sailesh Kumar G 37

38. Free hemoglobin in blood
 Normally very small amounts present
 Haptoglobin – plasma protein binds with this hemoglobin
 If small amounts leaks into renal tubules, it can be
reabsorbed and causes no harm
 But if it is in excess amounts, it precipitates in renal
tubules
 Blocks renal tubules
 Renal failure
 If the failure is complete, patient dies in a week to 12
days, unless treated with artificial kidney
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39. Collection of blood for transfusion, storage
and its changes during storage
 Typically 450 ml of blood is collected from vein
(antecubital vein)
 From a healthy donar who has been screened for
diseases that could be transmitted during
transfusion
 Autologous transfusion- donar blood is
transfused back to donar (after surgery)
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40. Collection of blood for transfusion, storage
 Blood is collected in a flexible plastic bag
 Which already has chemicals in it
 Sodium citrate – binds to calcium and prevents
clotting
 Phosphate buffer – to buffer the pH of blood and
provides source of phosphate
 Dextrose – energy source
 Adenine- to provide substrate to ATP synthesis
 By using these chemicals, the storage of blood can
be prolonged upto 35 days at 4 degrees centigrade
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41. Changes during storage
 RBC become spherical due to metabolic changes
 Change in cell rigidity of RBCS – los of membrane
flexibility and stability
 Leads to large destruction of RBCs in recipient blood
 Within the RBC, there is decrease in glycolysis, ATP and
2,3- DPG levels
 Granulocytes loose their phagocytic and anti bacterial
properties with in -6 hours
 Platelets become non functional with in 36-48 hours
 Potassium levels increases due to loss of potassium
from RBC into plasma DR Sai Sailesh Kumar G 41

42. Bombay blood group
 Bombay blood group, is a rare blood type.
 This blood phenotype was first discovered in
Bombay, now known as Mumbai, in India, by Dr.
Y. M. Bhende in 1952.
 It is mostly found in the Indian sub-continent
(India, Bangladesh, Pakistan) and parts of the
Middle East such as Iran.
 Individuals with the rare Bombay phenotype (hh)
do not express H antigen
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43. DR Sai Sailesh Kumar G 43

44. THANK YOU
DR Sai Sailesh Kumar G 44