Download 4 a.Blood groups ,transfusion react

Blood Groups
Multiple Blood Group Antigens
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30 common antigens
More than 100 uncommon antigens
Most of them are weak
ABO system of antigens very strong
Rh system also very strong
The ABO System
• Discovered in 1901 by Dr. Karl
Landsteiner
• 4 Main Phenotypes (A, B, AB, O)
• ABO gene located on long arm of
chromosome 9
ABO blood group system
• Two antigens (Agglutinogens)
– Agglutinogen A
– Agglutinogen B
• Two antibodies (Agglutinins)
– Agglutinin anti A or alpha (α ) antibody
– Agglutinin anti B or beta (β) antibody
ABO Antibodies
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A and B substances are the most common
Antibodies produced to “non-self” antigen
Produced after first few months of life
A & B people have mainly IgM
O people have IgG
May fade in old age
ABO Antibodies
ABO antigens found on surface of the
cell
ABO blood group system (Cont…)
• Four major groups
– Blood group A
– Blood Group B
– Blood group AB
are present
– Blood group O
are present
Agglutinogen A is present
Agglutinogen B is present
Both Agglutinogens A & B
None of the agglutinogens
ABO Blood Groups
A - A antigen only
B - B antigen only
AB - Both A and B antigens
O - Neither antigen
ABO Blood Group
ABO Blood Group
ABO Blood Group
ABO Blood Group
ABO Blood Group
Blood Group Markers
ABO Markers (antigen and antibodies)
Blood Type Antigen
Antibody
% population
(blood group)
A
A
Anti-B
40
B
B
Anti-A
10
AB
A&B
none
5
O
None
Anti-A &
Anti-B
45
Antigens and antibodies of ABO
blood Group system
Landsteiner’s Law
• In ABO blood group system
– When one antigen is present on the cell
membrane of RBCs, antibody which can react
with this antigen is always absent.
– And when one antigen is absent in the cell
membrane of RBCs, antibodies to this antigen
are always present in the plasma.
Blood Group Identification
ABO Identification
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A cells clump with anti-A
B cells clump with anti-B
AB cells clump with both
O cells do not clump
Genotypes of blood groups
• Three genes: A, B & O
• Two of these genes are present, one on
each of the paired chromosomes
• O gene is functionless and does not
produce antigen O
• Both A & B genes always express in the
form of Agglutinogen A and Agglutinogen
B respectively
Genotypes of blood groups (Cont…)
• Six possible combinations of these genes called
‘Genotypes’ can result, i.e. AA, AO, BB, BO, AB
& OO
• Four blood groups
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AA & AO will express as Blood Group A
BB & BO will express as Blood Group B
AB genotype will express as Blood Group AB
OO genotype will express as Blood Group O
• Every human being belongs to one of these six
genotypes and blood groups
ABO Genotypes and Phenotypes
Blood groups with their genotypes,
antigens and antibodies
GENOTYPE
BLOOD GROUP
AGGLUTINOGEN
AGGLUTININ
OO
O
None
Anti A
Anti B
OA or AA
A
A
Anti B
OB or BB
B
B
Anti A
AB
AB
A&B
None
Origin of agglutinins
• Gamma globulins (like all other antibodies)
• Mostly IgM & IgG immunoglobulins
• Level at birth is almost ZERO and titre
gradually increases after exposure to
respective antigen
• Small amount of antigen A & B enter into
the body via food and other routes &
produce respective antibody if that antigen
is absent on the cells.
Blood transfusion
• In blood transfusion
– Antigens of the donor are important. They
should not be given to a person who has
antibodies against these antigens
– The antibodies of the donor are NOT
important
– They are diluted in recipient's plasma
– Or their concentration falls too low in storage
Blood transfusion
• The antigens in the recipient’s RBC are
not important
• The antibodies in recipient’s plasma are
important
Universal Donor and Recipient
• Universal Donor
• Group O
– Carries no A or B
antigens
– Packed and processed
units have little
antibody
• Universal Recipient
• Group AB
– Patient has no anti-A
or anti-B present
– Cannot lyse any
transfused cells
– Beware: other
antibodies may be
present
Transfusion reactions
• Mismatched transfusion→ Transfusion
reaction
• IgG is divalent
• IgM is polyvalent
• Reaction between
Antigen & antibodies
→ Agglutination
• AGGLUTINATION
• Donor antigens and recepient antibodies
are important.
• Mismatched blood causes a transfusion
reaction.
• RBCs of donor blood are agglutinated.
• Agglutination of recipient’s blood does not
occur because plasma portion of the donor
blood immediately becomes diluted by all
the plasma of the recipient.
• The titer of infused agglutinins decrease.
• On the other hand, small amount of blood
infused cannot dilute recipient’s
agglutinins so recipient’s antibodies can
still agglutinate the mismatched donor
cells.Eventually either
• Immediate hemolysis by hemolysins(IgM
antibodies)
• Later hemolysis from phagocytosis of
agglutinated cells.
Agglutination
14-34
Transfusion reactions
• Hemolysin antibodies are responsible for
immediate hemolysis
Transfusion reactions
• Agglutination →Plugging of small blood
vessels by clumps
• Jaundice
• Renal shut down
• Transmission of many disease
– Hepatitis
– AIDS
– Infectious diseases
• Hb ___bilirubin___excreted in bile by the
liver. Increased bilirubin ____jaundice.
• If liver function is normal, the bile pigment
will be excreted into the intestines by the
liver bile.
 Jaundice usually does not appear unless
400ml of blood is hemolyzed in less than a
day.
Acute KIDNEY shut down:
1.An-Ab reaction___toxic substances from
hemolyzing blood_____renal
vasoconstriction.
2.Loss of circulating RBCs____circulatory
shock.
3.Free Hb +haptoglobin__excess of Hb
leaks through the glomerular membrane
into the kidney tubules.----renal tubular
blockage.______acute kidney shut down.
• Choose the best response
Q.1. In ABO blood group system:
a)Blood group A has anti A antibodies.
b)Blood group B has anti A antibodies.
c)Blood group O has no antibodies.
d)Blood group AB has anti A and anti B
antibodies.
Q 2.In blood transfusion reaction:
a)Blood of the donor can dilute recipient’s
antibodies.
b)Agglutination of the recipient’s blood
occurs.
c)RBC’s of the donor’s blood are
agglutinated.
d)Antigens of the recipient’s blood are
important.
• Q. 3. Regarding antibodies in ABO blood
group system:
a)These are of IgE type.
b)Mostly are of IgG and IgM type.
c)Level of antibodies are maximum at birth.
d)Titer gradually decreases after exposure
to respective antigens.
• Q.4 Regarding antigens of ABO blood
group system
a) Blood group A has agglutinogen B on the
cell membrane of RBCs.
b) Blood group B has agglutinogen A on the
cell membrane of RBCs.
c) Blood group AB has agglutinogen A and
B on the cell membrane of RBCs.
d) Blood group O has agglutinogen A and B
on the cell membrane of RBCs.
Thank-you
Questions ??