Download The Cell Membrane

The Basics Of Blood
Antigens: -
 Controlled by genes at unknown No. of



chromosomal loci.
Appearance by 40 days of I.U. Lifeunchanged till death.
Also present in tissues & tissue fluids.
Blood group system: A group of antigens
controlled by a locus having a variable no of
allele genes.
AP Biology
1
The Basics Of Blood
Antigens: -
 > 15 blood group systems are recognised :
ABO, Rh, Kell, Duffy, MN, P, Lewis, Lutheran,
Xg, Li, Yt, Dombrock, Colton, Public antigens
& Private antigens.
Blood type- means individual antigen
phenotype which is the serological expression
of the inherited genes
Most of these blood group antigens have been
found to be associated with hemolytic disease.
However– ABO & Rh account for 98%




AP Biology
2
The Basics Of Blood
Antibodies: -
Alloantibodies / Agglutinins
Natural
IgM
Iso / immune antobodies
IgG
Formed in response to
foreign R.B.C. or soluble
blood group substance.
AP Biology
3
The Basics Of Blood
Natural Antibodies: -
 Antibodies are formed against most of the major




group antigens & present in almost all individuals
when the antigen is absent.
In most other minor systems, natural antibodies to
the antigens are found occassionally but as their
anitgenicity is low, the immune antibodies are also
rare ( except –Kell & Duffy)
Mostly of them are IgM type.
React poorly at body temp. ( except anti-A & antiB), but agglutinate R.B.C.s at 5-20°C
Usually do not cross placenta.
AP Biology
4
The Basics Of Blood
Immune Antibodies: -
 In contrast the immune or isoantibodies are


IgG.
Best react at body temp. & readily cross
placenta.
Most antibodies are complement binding
notable exceptions being Rh & MN.
AP Biology
5
Antibodies Can Be Detected by: a. Saline agglutination test (SAT).
b. Tests using cells suspended in colloid media.
c. Tests using enzyme-treated cells- Rh &
d.

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occasional antobodies.
Indirect antiglobulin ( Coomb’s test) - wide
spectrum.
Antibodies may be Complete / Incomplete


IgM
IgG
Detected by
SAT
b, c, d
6
ABO Blood Grouping
AP Biology
ABO Basics
 Blood group antigens are actually
sugars attached to the red blood cell.
 Antigens are “built” onto the red cell.
 Individuals inherit a gene which codes
for specific sugar(s) to be added to the
red cell.
 The type of sugar added determines the
blood group.
AP Biology
Introduction to Blood
ABO blood groups found on outside of cell
AP Biology
Introduction to Blood
ABO blood groups found on outside of cell
AP Biology
Introduction to Blood
 RBC = no DNA; WBC = yes DNA

All blood cells have blood groups on
outside of cell.

Red Blood Cells contain the protein
hemoglobin, which carries oxygen
AP Biology
Introduction to Blood
Hemoglobin picks up and drops off oxygen
AP Biology
This diagram illustrates the terminal sugar
for each blood group.
AP Biology
ABO Type Frequencies In U.S.
AP Biology
ABO Type
Per Cent
O
45%
A
40%
B
11%
AB
4%
Landsteiner’s Rule
 Individual’s will form immune antibodies to
ABO blood group antigens they do not
possess.
 Substances are present in nature which are
so similar to blood group antigens which
result in the constant production of
antibodies to blood group antigens they do
not possess.
 Critical for understanding compatibility
between ABO blood groups.
AP Biology
Antibody clinical significance
 Immunizations are frequently done to
protect us from disease.




Receive Hepatitis B immunization.
Actual bits of hepatitis virus injected.
Body recognizes as foreign and produces an
immune antibody.
Subsequent exposure to real Hepatitis B virus will
result in destruction of the virus by immune
antibodies.
 ABO antibodies are immune and will result
in destroying incompatible cells which may
result in the death of the recipient.
AP Biology
Inheritance
 Blood group antigens are
“codominant”, if the gene is inherited,
it will be expressed.
 Some aberrant genotypes do occur but
due to the rarity will not be discussed.
 Understanding of basic inheritance
important.
AP Biology
Genetics
 Two genes inherited, one from each parent.
 Individual who is A or B may be
homozygous or heterozygous for the
antigen.
 Heterozygous: AO or BO
 Homozygous: AA or BB
 Phenotype is the actual expression of the
genotype, ie, group A
 Genotype are the actual inherited genes
which can only be determined by family
studies, ie, AO.
AP Biology
Example of Determining Genotype
 Mom’s phenotype is group A, genotype AO
 Dad’s phenotype is group B, genotype BO
B
O
A
AB 25%
O
BO 25% (Group B) OO 25% (Group O)
AP Biology
AO 25% (Group A)
Other Examples
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Mom
Dad
AA
BB
BO
OO
OO
OO
OO
AO
Offspring Blood
Group
100% AB
50% each of B
or O
100% O
50% each of A
or O
Group O
 Approximately 45% of the
population is group O.
 No A or B antigens present,
think of as “0” antigens
present.
 These individuals form potent
anti-A and anti-B antibodies
which circulate in the blood
plasma at all times.
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Group A
 Approximately 40% of
the population is group
A.
 No B antigens present.
 These individuals form
potent anti-B antibodies
which circulate in the
blood plasma at all
times.
AP Biology
Group B
 Approximately 11% of the
population is group B.
 No A antigens present.
 These individuals form
potent anti-A antibodies
which circulate in the blood
plasma at all times.
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Group AB
 Approximately 4% of the
population is group AB.
 Both A and B antigens
present.
 These individuals
possess no ABO
antibodies.
 NOTE: This slide is in
error as it only illustrates
presence of one antigen
not 2.
AP Biology
Hemolysis
 If an individual is transfused with an

incompatible blood group destruction of
the red blood cells will occur.
This may result in the death of the
recipient.
AP Biology
Summary
Blood Group
Antigens on cell
Antibodies in
plasma
Transfuse with
group
A
A
Anti-B
A or O
B
B
Anti-A
B or O
AB
A and B
none
O
None
Anti-A & B
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AB, A, B or O
O
The Rh(D) Antigen
 RH is the most complex system,



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with over 45 antigens
Discovered in 1940 after work on
Rhesus monkeys
Subsequently discovered to be
unrelated to monkeys
RH gene located on short arm of
chromosome 1
ABO & Rh(D)
27
Rhesus Blood Group System
 First demonstrated by testing human blood with
rabit anti sera against red cells of Rhesus
monkey & classifying Rh negative & Rh positive.
 However the underlying biochemical genetics is
not well understood and the genotyping &
phenotyping remains little confused
 The genotype is determined by the inheritance of
3 pairs of closely linked allelic genes situated in
tanderm on chromosome 9 & named as D/d, C/c,
E/e (Fisher- Race theory)
AP Biology
28
Rhesus Blood Group System
 The gene ‘d’ is an amorph & has no antigenic




expression. So there are only five effective
antigens.
But Weiner postulates a series of allelic genes at
a single locus Rho (D), rh (C),rh (E), hr © & hr (e)
The updated system of Rosenfield refers these
antigens as – Rh1, Rh2, Rh3, Rh4, Rh5
Subsequently less common antigens Cw, Du, Es
have been found
The foetus inherits one gene from each group as
a haplotype such as sets of Cde, cde etc from
each parent
AP Biology
29
Rhesus Blood Group System
 12 sets of combinations & 78 genotypes are
possible. Most frequent genotypes are –
 Cde/cde(33%), Cde/cDe(18%), Cde/cDE(12%)
cDE/cde(11%), cde/cde(15%), cdE/cde(1%),
Cde/cde(1%)
 Though several Rh genotypes and phenotypes
have been described, for clinical & all practical
purposes it is enough to know whether one is Rh
POSITIVE or NEGATIVE against anti D sera.
AP Biology
30
Rhesus Blood Group System
 Incidence of Rh negative varies in different races:
Mongoloids- nil, Chinese & Japanese- 1-2%,
Indians-5%, Africans-5-8%, Causcasians-1517% & Basques-30-35%.
 The antigenic expressions of these genes are
dependent on an interaction between R.B.C.
membrane protein & phospholipid molecules
resulting in a set of antithelical epitopes, the
coresponding antigens, consisting of C/c, D/d,
E/e.
 The antigenic determinants form an intrinsic part
of the red cell membrane protein structure.

AP Biology
31
Rhesus Blood Group System
 C/c & E/e are weak antigens and impractical to
match.
 ‘D’ is by far the most immunogenic in the Rh
system excepting those that have the natural
antibodies.
 There is a rare type of Rh negative called Rh null
who lack all known Rh antigens.
 ‘D’ antigen has no natural antibody while C & E
have the coresponding natural antibodies, though
weak & found infrequently.
AP Biology
32
Rhesus Blood Group System
 A single transfusion of + ve blood to a – ve
person has a 50% chance of forming anti Rh D
antibodies (IgG)
 Anti Rh antibodies are of three categories 1st order – saline / bivalent / complete
antibodies
 2nd order - albumin active / univalent /
incomplete antibodies
 3rd order – atypical / antiglobulin active /
incomplete antibodies
AP Biology
33
Simple Genetics of Rh(D)
 86% of caucasians are Rh(D) pos
 The antithetical antigen d has not been

found
The d gene is recessive:
Dd, dD, DD, persons are Rh(D) pos
 Only dd persons are Rh(D) neg

AP Biology
ABO & Rh(D)
34
Distribution of Rh(D) Types
Population
Rh(D) pos
Rh(D) neg
Caucasian
86%
14%
AfricanAmerican
95%
5%
Oriental
>99%
<1%
AP Biology
35
ABO
& Rh(D)
Significance of Rh(D)
 80% of Rh(D) neg persons exposed to

Rh(D) pos blood will develop anti-D
Anti-D can also be stimulated by
pregnancy with an Rh(D) positive baby

Sensitisation can be prevented by the use of
anti-D immunoglobulin, antenatally and post
natally
 Rh(D) neg females of childbearing
potential should never be given Rh(D)
positive blood products
AP Biology
ABO & Rh(D)
36
Inheritance
 ABO & RH genes are not linked
 ABO & Rh(D) type are inherited
independently
For example:
An A Rh(D) pos mother
and a B Rh(D) pos father
could have an O Rh(D) neg child
AP Biology
ABO & Rh(D)
37
Inheritance of ABO and Rh(D)
Mother
Group A
Father
AO
Group B
Rh(D) pos Dd
BO
Rh(D) pos Dd
Group A AO
Group B BO
Group O OO
Rh(D) pos Dd
Rh(D) pos Dd
Rh(D) neg dd
AP Biology
ABO & Rh(D)
38
Hemolytic Disease of the Neborn
– How it Occurs
 A child is Rh pos
 B during pregnancy fetal Rh pos rbc’s escape into
maternal circulation
 C Mother produces antibodies to Rh (D) antigen
 D Second pregnancy with Rh (D) pos child results in
destruction of fetal D pos rbcs
AP Biology
Pathogenesis Of Rh Iso-immunisation
Rh Negative Women
Man Rh positive (Homo/Hetero)

Rh Neg Fetus

No problem


Fetus  
Mother previously sensitized
Secondary immune response

? Iso-antibody (IgG)

Fetus

Haemolysis
AP Biology
 

 
  ?
Rh positive Fetus

Rh+ve R.B.C.s enter
Maternal circulation

Non sensitized Mother
Primary immune response

Fetus  unaffected, 1st
Baby usually escapes.
Mother gets sensitised? 

40
Pathogenesis Of Rh Iso-immunisation
 Chances of T.P.H/F.M.H. are only 5% in 1st
trimester but 47% in 3rd trimester, many
conditions can increase the risk.
 Chances of primary sensitization during 1st
pregnancy is only 1-2%, but 10 to 15% of patients
may become sensitized after delivery.
 ABO incompatibility and Rh non-responder status
may protect.
 Amount of antibodies that enter the fetal
circulation will determine the degree of
haemolysis
AP Biology
41
Pathology Of Iso-immunisation
AFTER BIRTH

HAEMOLYSIS



Jaundice
Kernicterus
Hepatic Failure



DEATH
ANAEMIA

IUD

ERYTHROBLASTOSIS
FETALIS




IN UTERO

BILLIRUBIN

 HEPATIC
ERYTHROPOESIS
& DYSFUNCTION
MAT. LIV NO
EFFECT

PORTAL & UMBILICAL VEIN
 HYPERTNSION, HEART FAILURE






BIRTH OF AN AFFECTED INFANT - Wide spectrum of presentations. Rapid
deterioration of the infant after birth. May contiune for few days to few months.
Chance of delayed anaemia at 6-8 weeks probably due to persistance of anti Rh
antibodies.
AP Biology
42
Prevention of Rh Incompatibility
 Premarital counseling? Ambitious?
 Proper matching of blood particularly in



women before childbearing.
Blood grouping must for every woman,
before 1st pregnancy.
Rh+ve Blood transfusion- 300mcg
Immunoglobulin (minimum).
Proper management of unsensitised Rh
negative pregnancies.
AP Biology
43
Management of Unsensitised Pregnancy
 Blood typing at 1st visit, If negative husband’s
typing. If husband is also negative then no
treatment
 If husband is positive, if possible, Homo/Hetero?
 Do Indirect Coomb’s test of mother –
 Negative-good.
 Repeat ICT at 28 weeks – Negative- ICT at 35
weeks - Negative- Observe
 Positive Sensitised - 300mcg Rh
immunoglobulin
AP Biology
44
Management of Unsensitised Pregnancy
 In Abortion, Ectopic, CVSPregnancy < 12 weeks- 50mcg Anti D
 Pregnancy >12 weeks- 300mcg Anti D

 APH, IUD, Amniocentesis, Abdominal
trauma, Foetal-maternal hemorrhage 300mcg Anti D
 At birth- cord blood for ABO & Rh
typing
 Baby Rh negative – Be happy
AP Biology
45
Management of Unsensitised Pregnancy
 If Rh positive- Test mother’s blood for
ICT & Infant’s for DCT
Negative or weakly reactive- 300mcg
immunoglobulin
 Positive – Sensitised–Hb & Bilirubin
Estimation of the infant -Treat the infant

 ?Prophylactic Anti D administration
during antenatal period to all negative
mothers at 28weeks and again at 34 / 36
weeks.
AP Biology
46
Management of Sensitized Pregnancy
 Causes of sensitizationMisinterpretation of maternal Rh type
 Rh +ve blood transfusion
 Unprotected preg. & labour
 Inadequate dose / improper use of
IgG on previous occasions
 Immunization to cross-reacting
antigen

AP Biology
47
Management of Sensitized Pregnancy
 Careful planning during antepartum,
intrapartum & neonatal period
 Father’s blood type & Rh antigen status
 Knowledge of maternal antibody titer to
the specific antigen
 Intrauterine foetal monitoring with
repeated ultrasound examination,
cordocetesis / amniocentesis
AP Biology
48
Management of Sensitized Pregnancy
 Fetus Rh Negative: - Observation
 Fetus Rh Positive: Intrauterine transfusion of ‘Rh Neg’
blood as indicated
 Timely delivery any time after 32 weeks
 Management of the infant up to 8 weeks

 In cases of severely sensitized women,
consider medical termination of
pregnancy and sterilization .
AP Biology
49
Blood Typing
 There are 2 components to blood
typing:
Test unknown cells with known
antibodies
 Test unknown serum/plasma with
known rbc’s

 The patterns are compared and the
blood group is determined.
AP Biology
Slide Blood Typing
 Very rudimentary method for determining
blood groups.
 CANNOT be used for transfusion purposes
as false positives and negatives do occur.
 A “false positive” is when agglutination
occurs not because the antigen is present,
but cells may already be clumpled.
 A “false negative” is one in which the cells
are not clumped because there are too
many cells or not enough reagent.
AP Biology
Slide Blood Typing - continued
 The slide is divided into halves.
 On one side a drop of anti-A is added, this will



attach to and cause clumping of rbcs possessing
the A antigen.
On the other side a drop of anti-B is added which
will cause clumping of rbcs with the B antigen.
A drop of rbcs is added to each side and mixed
well with the reagent.
The slide is tilted back and forth for one minute
and observed for agglutination (clumping) of the
rbcs
AP Biology
Interpretation of Slide Typing
Testing with Anti-A Anti-Serum
 If an rbc contains the A
antigen the red blood cells
will be agglutinated by antiA, a positive reaction.
 If an rbc does not have the
A antigen there will be no
clumping, a negative
reaction.
AP Biology
Interpretation of Slide Typing
Testing with Anti-B Anti-Serum
 If an rbc contains the B
antigen the red blood cells will
be agglutinated by anti-B, a
positive reaction.
 If an rbc does not have the B
antigen there will be no
clumping by anti-B, a negative
reaction.
AP Biology
Slide Blood Typing Group A
 An unknown rbc suspension is added to known
anti-sera.
 The left hand of the slide contains anti-A which
reacts with the unknown cell.
 The right hand side contains anti-B which does not
react with the cell.
AP Biology
Slide Blood Typing Group B
 An unknown rbc suspension is added to known
anti-sera.
 The left hand of the slide contains anti-A does not
react with the unknown cell.
 The right hand side contains anti-B which reacts
with the cell.
AP Biology
Slide Blood Typing Group O
 The left hand of the slide contains anti-A
does not react with the unknown cell.
 The right hand side contains anti-B does
not react with the unknown cell.
AP Biology
Slide Blood Typing Group AB
 The left hand of the slide contains anti-A
which reacts with the unknown cell.
 The right hand side contains anti-B which
reacts with the unknown cell.
AP Biology
Summary of Slide Typing
AP Biology
Anti-A
Anti-B
Blood Group
NEG
NEG
O
POS
NEG
A
NEG
POS
B
POS
POS
AB
The ABO Antigens
 Added to Proteins or Lipids in Red Cells
 Substrate Molecule is H (fucose)
 A antigen is N-acetyl-galactosamine
(GalNAc)
 B antigen is Galactose (Gal)
 A and B genes code for transferase
enzymes
AP Biology
ABO & Rh(D)
60
ABO Antibodies
 A and B substances very common
 Antibodies produced to “non-self”
 Produced after first few months of life
 A & B people have mainly IgM
 O people have IgG
 May fade in old age
AP Biology
ABO & Rh(D)
61
Distribution of ABO Groups
Population
Aborigines
Basques
Blackfoot (N. Am. Indian)
Bororo
Chinese-Canton
Chinese-Peking
English
Hawaiians
Irish
Mayas
Navajo (N. Am. Indian)
Peru (Indians)
United Kingdom (GB)
USA (blacks)
USA (whites)
AP Biology
ABO & Rh(D)
O
A
B
AB
61
51
17
100
46
29
47
37
52
98
73
100
47
49
45
39
44
82
0
23
27
42
61
35
1
27
0
42
27
40
0
4
0
0
25
32
8
2
10
1
0
0
8
20
11
0
1
1
0
6
13
3
1
3
1
0
0
3
4
4
62
Distribution of the A allele
AP Biology
ABO & Rh(D)
63
Distribution of the B Allele
AP Biology
ABO & Rh(D)
64
Distribution of the O Allele
AP Biology
ABO & Rh(D)
65