Download MORPHOLOGIE DES HEMATIES Normales et Pathologiques

Other blood groups
Several other blood group antigens have
been identified in humans. Some examples:
MN, Duffy, Lewis, Kell.
 They, too, may sometimes cause transfusion
reactions and even hemolytic disease of the
newborn in cases where there is no ABO or
Rh incompatibility.
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Lewis Blood Group System
Le
 The 7th blood groud.
 ABH and Lewis Ag are much related together
biochemically. Both have the same basic structure
(15 Amino Acids), they are glycoproteins.
Lewis Ag:
 Soluble Ag
 Production governed by two genes Le a & Le b
 At birth, there is no Lewis Ag.
 It takes 3-4 years for the Ags to become strong on
the surface of the RBCs.
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Lewis Ab:
Anti Le a
Anti Le b
Agglutinate blood in saline (IgM), work best at
20oC, and fix the complement.
Do not cause HDN of new born because:
 Ag not developed yet.
 IgM, can not cross the placenta.
Bombay Phenotype
It is an abnormal blood group.
Discovered in Bombay in 1952.
ABO system

There are 3 genes, are controlled the
synthesis of specific enzymes responsible
for addition of single carbohydrate
residues:
N. acetyl Galactoseamin= A antigen.
 D.galagtose = B antigen.
 Fucose = H antigen = O blood group.
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?
= AB blood group
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It is important to be cautious in predicting the
ABO blood type of children based on the
phenotypes of their parents. This is due to the
fact that a third antigen (H) on the surface of red
cells can prevent the expected ABO blood type
from occurring.
Normally, if an A blood type mother has an O
type child; the father is expected to be type O or
at least to carry the O allele (OO, AO, or BO
genotype).
The child has inherited an O allele from both
parents. However, an O blood type child can also be
born to parents who do not have the O allele if a
recessive form of the allele for the H antigen also is
inherited from both parents.
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The H antigen is a precursor to the A and B
antigens. For instance, the B allele must be present to
produce the B enzyme that modifies the H antigen to
become the B antigen. It is the same for the A
allele. However, if only recessive alleles for the H
antigen are inherited (hh), as in the case above, the H
antigen will not be produced. Subsequently, the A and B
antigens also will not be produced. The result is an O
phenotype by default since a lack of A and B antigens is
the O type.
This seemingly impossible phenotype result has been
referred to as a Bombay phenotype because it was first
described in that Indian city.
Antigens of rhesus blood group
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There are 2 different terms are used to
describe these antigens.:
Weiner,s Ag,s ( Rho, rh’, rh”, hr’, and hr” ).
Fisher & Race Ags ( D, C, E, c’, and e’ ).
The most important Ags in weiner is ( Rho
)
The most importnant Ags in fisher and
race is ( D )
Rhesus (Rh) blood grouping system
Antigens:
 This is one of the most important blood grouping systems.
 Named because it was first discovered in rhesus monkeys
 In 1940 Landsteiner and Wiener showed that antibodies
produced against the rhesus monkey RBCs agglutinated
RBCs of 85% of a human population.
 The antibodies were directed against a molecule called the
rhesus (Rh) antigen, and individuals possessing it were
called Rh positive.
 Natural antibodies against the Rh antigens do not occur.
The gene product is identified as the RhD
antigen or D antigen.
 Rh system is very complex, and our present
understanding is based on the Fisher system.
 Three genes making up Rhesus antigens: C,
D, and E, found on chromosome 1, the D Ag
is the most important one.
 There are two possible alleles at each locus:
c or C; d or D; and e or E.
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One haplotype consisting of c/C, d/D, e/E is inherited
from each parent, and the resulting Rhesus type of
the individual depends on their inherited genotype,
this will lead to the following genotypes CDe, cDE,
cde, cDe, Cde, cdE, CdE, cde.
If an individual's Rh genotype contains at least one of
the C, D, E antigens, they are Rhesus positive.
Only individuals with the genotype cde/cde (rr) are
Rhesus negative.
The most common Rh antibody is anti-D, but it is
possible to form antibodies to c, C, e, and E as well,
and to form combinations of antibodies. There is no
anti-d.
Other Rh Ags:
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Cw Ag:
Very rare, and can causes HDN, and HTR.
G Ag.
Du Ag: it is an important Ag, which must be
regarded as D Ag. in Nigeria, 8% of the
people type as D-, are Du. Very strong AntiD Ab should be used to detect Du Ag.
Antibodies to the Rh system:
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No naturally occurring.
All the Ab are immune IgG Abs.
All the six Ags will produce immune Abs when
given to people not from the same Rh group.
D>c>E>e>C
Abs can cause HDN and HTR.
 In
any of the 4 ABO groups, a
person can be Rh positive or Rh
negative, meaning that a person’s
blood can be classified as one of 8
possible types
(O+, O-, A+, A-, B+, B-, AB+, AB-).