Rhesus Isoimmunization

1
Rhesus Isoimmunization
Dr Esgair Alzahra MBBCH, DOG, ABOG
A . Prof. Alfateh Medical Sciences Faculty of
medicine Ob and gy department Tripoli Libya
Consultant Obstetrician and Gynecologist Aljala
teaching Hospital Oumer Almokhtar Street

Tripoli Libya
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4 Basic Blood Types

1. A (surface antigen A)
2. B (surface antigen B)
3. AB (antigens A and B)
4. O (neither A nor B)

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ABO System Pregnancy
hemolytic diseases of the newborn may be due to
ABO incompatibility
Fetus inherits one gene from each parent.
O O O, O A O or A,
O B O or B, O AB O
or A B
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Rhesus Blood Group System
First demonstrated in Rhesus monkey
Blood group are classified as Rh negative or
Rh positive
However the underlying biochemical genetics is
not well understood and the genotyping
phenotyping remains little confused
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Rhesus Blood Group System
The genotype is determined by the inheritance of
3 pairs of closely linked allelic genes situated
on chromosome 9 named as D/d, C/c, E/e ..
(Fisher- Race theory)
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Rhesus Blood Group System
Weiner postulates a series of allelic genes at a
single locus Rh (D), Rh (C), Rh (E), Rh (c) Rh
(e)
The gene ( d ) is an amorph has no antigenic
expression. So there are only five effective
antigens
The updated system of Rosenfield refers these
antigens as Rh1, Rh2, Rh3, Rh4, Rh5
Subsequently less common antigens Cw, Du, Es have
been found
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Rhesus Blood Group System
The fetus inherits one gene from each group as a
haplotype such as sets of Cde, cde etc from each
parent
12 sets of combinations 78 genotypes are
possible.
Most frequent genotypes are
Cde / cde (33), Cde / cDe (18),
cde / cde (15), Cde / cDE (12) cDE
/ cde (11), cdE / cde (1), Cde /
cde (1)
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Rhesus Blood Group System
Incidence of Rh negative varies in different
races
Mongoloids gt 1, Chinese
Japanese 1-2, Indians
5, Africans 5-8,
Caucasians 15-17 Basques
30-35.
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Rhesus Isoimmunization
Rhesus Iso immunization is an immunologic
disease that occurs in pregnancy resulting in a
serious complication affecting the fetus / or the
neonate ranging from mild neonatal jaundice
to intra uterine loss or neonatal death
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Rhesus Isoimmunization
This immunologic disease occur when a Rh
negative patient carrying a Rh positive fetus
.. had a feto maternal blood transfusion ..
the mother immunological system is stimulated
to produce antibodies to the Rh antigen on
the fetal blood cell .. This
antibodies cross the placenta and destroy
fetal red blood cells leads to fetal anemia .
Usually the 1st fetus will not be affected if
this is the 1st time that the mother has
been exposed to the rhesus positive
antigen
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During pregnancy while the fetus still in the
uterus The bilirubin in the fetal blood will be
removed by the placenta to the maternal
circulation and part of it go to the liquor
The fetus will be anemic .. If the degree of
anemia is severe fetus may die in utero
because of heart failure
After delivery The neonate will affected by
The degree of the anemia The amount of
bilirubin
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Antigens
Anything that can trigger an immune response
Most are protein
Surface Antigens
cell surface proteins that identify cells to
immune system
Normal cells are ignored and foreign cells
attacked
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Antigens
Controlled by genes at chromosomal loci.
Appearance by 40 days of I.U. Life unchanged till
death.
Also present in tissues tissue fluids
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Blood cell Types
Blood group system A group of antigens
controlled by a locus having a variable
no of allele genes.
Are genetically determined
By the presence or absence of RBC surface
antigens the blood group can be named A, B, AB,
or O
Rh positive or Rh negative
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Blood cell Antigens
Blood Group type- means.. Individual antigen
phenotype which is the serological expression of
the inherited genes

• 15 blood group systems are recognized
• ABO, Rh, Kell, Duffy, MN, P, Lewis, .

These blood group antigens have been found to be
associated with hemolytic disease.
However ABO Rh account for 98
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Antibodies
Natural IgM
Iso / Immune antibodies IgG
Formed in response to foreign R.B.C.
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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
anti-B), but agglutinate R.B.C.s at 5-20C
Usually do not cross placenta.
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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
Antibodies may be Complete / Incomplete
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Antibodies Can Be Detected by
Saline agglutination test (SAT).
a
Tests using cells suspended in colloid media.
b
c
Tests using enzyme-treated cells- Rh
occasional antobodies.
d
Indirect antiglobulin ( Coombs test) - wide
spectrum.
IgG Detected by ? SAT IgM Detected by ?
b, c, d
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W.B.C. Platelet
R.B.C.
Plasma
ANTIBODY
ANTIGEN gt400 Agglutinogens on the cell
membrane
Antigen-Antobody reaction on the cell surface ?
Hemolysis
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ABO Blood Group System
ABO system is controlled by allelic genes A1, A2,
B, O located on the long arm of chromosome 9
The loci of ABO H are not genetically linked
A1 A2 genes perform same function but have a
different rate constant
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ABO Blood Group System
The O gene is an amorph functionaly silent
The H antigen is a precursor to A B
Secretors non secretors Se se genes control
the production of a flucosyl transferase, which
controls the production of H, A B antigens in
tissues
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ABO Blood Group System
Genotype (Genes) Phenotype (Blood type) Antigens in R.B.C. Antibody In plasma
A1 A1 , A1 A2 A2 A2, A2 O A1 (23-25) A2 (6-10) A1, (H) A2, (H) anti-B, anti-H Anti-B, anti-A1
BB, BO B(8-17) B,(H) Anti-A/A1
A1B A2 B A1B(3) A2B(1) A,A1,B A,B,H Anti-H Anti-A1
O,O H,h O(43-50) Oh Bombay H None Anti-A,-A1,-B Anti-A,-A1,-B,-H
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ABO System Pregnancy
There is a 20 chance of ABO incompatibility of
mother fetus if feto maternal Hemorrhage occur
Less than 5 chance of developing noticeable
hemolytic disease ( milder forms )
It is more prominent in type A B infants of
type O mothers
In fetus newborn, RBCs have a decreased No. of
H, A B reactive sites
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ABO System Pregnancy
The fetal immunoglobulin production is low, so
the plasma contains very little of anti-A B
agglutinins
Anti-A B produced in the mother being natural
are IgM molecules so do not cross placenta.
In some type O adults, much of the anti-A B and
anti-AB (a cross reacting antibody, also called
anti-C) isoagglutinins are of IgG class.
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ABO System Pregnancy
There is no adequate method of antenatal diagnosis
Direct Coombs antiglobulin test may be negative
in ABO haemolytic disease
ABO haemolytic disease is frequently seen in
infants of primigravidae the chance of
recurence is 87.
The risk of stillbirth is not increased no
antenatal treatment is necessary
Only 67 of affected infants will need any
treatment
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Rhesus Blood Group System
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
C/c E/e are weak antigens and impractical to
match
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Rhesus Blood Group System
D is by far the most immunogenic in the Rh
system
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 corresponding natural antibodies, though
weak found infrequently.
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D is by far the most immunogenic in the Rh
system
A single transfusion of Rh positive ( ve )blood
to an Rh negative ( - 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
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Pathogenesis Of Rh Iso - immunisation
Rh Negative Women
Man Rh positive (Homo/Hetero)
Man Rh positive (Homo)
?
Rh positive Fetus
Fetus
?
?
Rhve R.B.C.s enter Maternal circulation
previously sensitized 2nd immune response
?
?
?
Non sensitized Mother Primary immune response
IgMIgG antibodies
?
Fetus
?
1st Baby usually escapes. Mother gets sensitized?
?
?
Haemolysis
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Pathogenesis Of Rh Iso - immunisation
Rh Negative Women
Man Rh positive (Hetero)
?
Rh Neg Fetus No problem
Fetus
Rh positive Fetus
?
?
?
Rhve R.B.C.s enter Maternal circulation
previously sensitized 2nd immune response
?
?
?
Non sensitized Mother Primary immune response
IgMIgG antibodies
?
?
Fetus
1st Baby usually escapes. Mother gets sensitized?
?
?
Haemolysis
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IN UTERO
Antigen-Antibody reaction on the RBCs surface ?
Hemolysis
Anemia
?
? Hepatic erythropoesis dysfunction
?
Portal Umbilical Vein Hypertension Heart
Failure
?
Erythroblastosis fetalis
?
IUD
Polyhydramnios
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After birth
Antigen-Antibody reaction on the RBCs surface
?
Hemolysis
?
Anemia Jaundice Kernicterus
?
Neonatal death
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Pathogenesis Of Rh Iso - immunization
ABO incompatibility and Rh non-responder status
may protect
Chances of feto-maternal hemorrhage are only 5
in 1st trimester but 47 in 3rd trimester,
Chances of primary sensitization during 1st
pregnancy is only 1-2
Up to 15 of patients may become sensitized
after delivery
Amount of antibodies that enter the fetal
circulation will determine the degree of
haemolysis
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Pathogenesis Of Rh Iso - immunization
HAEMOLYSIS
?
?
IN UTERO
AFTER BIRTH
?
?
?
Jaundice Kernicterus Hepatic Failure
Jaundice Kernicterus Hepatic Failure
?BILLIRUBIN
ANAEMIA
?
?
MAT. LIV NO EFFECT
? HEPATIC ERYTHROPOESIS DYSFUNCTION
?
?
DEATH
IUD
DEATH
?
?
?
?
?
?
PORTAL UMBILICAL VEIN HYPERTNSION, HEART FAILURE
ERYTHROBLASTOSIS FETALIS
?
?
?
?
?
?
?
?
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.
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Rh Iso - immunization
Premarital counseling?
Proper matching of blood particularly in women
before childbearing
Blood grouping must be for every woman, In her
1st pregnancy
Proper management of unsensitized Rh negative
pregnancies
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Management of rhesus negative pregnant women
Management of non sensitized Pregnancy
Management of sensitized Pregnancy
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Management of non sensitized Pregnancy
Non sensitized Rh Neg. mothers married to a Rh
Pos. husband
Blood Group typing at 1st visit, If negative
Check husbands Blood Group typing. If
husband is also Rhesus negative then no rhesus
complication and manage as other
pregnant women If husband is Rh Positive then
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Management of non sensitized Pregnancy
Non sensitized Rh Neg. mothers married to a Rh
Pos. husband
If husband is Rh Positive then Check Husband
being Homozygous or Heterozygous .... Check for
maternal antibodies by indirect Comb's test
( ICT ) if antibodies detected
treat as sensitized If no
antibodies Repeat ( ICT ) at 28
and 32 weeks provided that no bleeding.
If there is bleeding then ..
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Management of non sensitized Pregnancy
Bleeding before 20 weeks of gestation ..
Check for fetal red blood cells in
maternal circulation by Kleihauer test ..
Check for maternal antibodies ( ICT ) if
negative .. Give ( 250 IU / 50 mcg ) anti D
to the mother within 72 hours from
the bleeding
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Management of non sensitized Pregnancy
Bleeding after 20 weeks of gestation ..
Check for fetal red blood cells in
maternal circulation by Kleihauer test ..
Check for maternal antibodies ( ICT ) if
negative .. Give ( 500 IU / 100 mcg ) anti D
to the mother within 72 hours from
the bleeding .. The dose should be doubled or
tripled if fetal RBCs are more than
80 cells in maternal circulation
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Prophylactic Management of non sensitized
Pregnancy
During antenatal period Prophylactic (500 IU /
100 mcg ) Anti D are recommended to be given to
all
negative non sensitized mothers married to Rh
positive husband at 28weeks and 34 weeks to
protect and overcome any asymptomatic or un
noticed antenatal feto maternal blood
transfusion
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Prophylactic Management of non sensitized
Pregnancy
Indications for prophylaxis At 28weeks to a
Rhesus ve non sensitized woman whose husband is
Rhesus ve Postpartum if the woman remains non
sensitized and delivers a Rhesus ve
fetus Following amniocentesis or chorionic
villus sampling Following evacuation of a molar
pregnancy or termination of pregnancy Following
an ectopic pregnancy Following abruptio placenta
or undiagnosed uterine bleeding
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Prophylactic Management of non sensitized
Pregnancy
Failure of prophylaxis Dose too small Dose too
late gt72 hours Patient already immunized but
antibody titer too low for laboratory
recognition Defective immune globulin given
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Management of non sensitized Pregnancy
Precaution should be taken to prevent the
possibility of increased chance of feto -
maternal blood transfusion At birth
During labor No fundal pushing in 1st or 2nd
stage of labor No uterine massage or uterine
grasp and squeeze in 3rd stage Let the
placenta to be delivered spontaneous A void
avulsions of the cord Protect the vaginal and
perineal wounds and laceration from being
exposed to the fetal blood spilled from cord
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Management of non sensitized Pregnancy
During cesarean section Use abdominal packs in
the sides of the uterus before opening the
lower segment to prevent spilled blood from
the placenta to inter the peritoneal
cavity. Let the placenta to be delivered
spontaneous using control cord traction
without squeezing the uterus A void
avulsions of the cord
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Management of non sensitized Pregnancy
At birth . Maternal blood sample for
.. antibodies by indirect Comb's test ( ICT
) .. fetal red blood cells in
maternal circulation
. Cord blood sample ( Neonatal blood sample )
for .. antibodies by Direct Comb's
test ( DCT ) .. Infant blood group
.. Infant bilirubin level
.. Infant Hb Hct level
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Management of non sensitized Pregnancy
. If fetal blood group is rhesus positive .
No antibodies detected
Give full dose of Anti D ( 500 IU / 100 mcg ) to
the mother within 72 hours after delivery
The dose should be corrected according to the
number of fetal red blood cells present in the
maternal circulation
Dont give Anti D . If fetal blood group is
rhesus negative . If Antibodies detected
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Sensitized Rh Negative mothers
Causes of sensitization Misinterpretation of
maternal Rh type Rh positive blood
transfusion Unprotected pregnancy
labour Inadequate dose Anti D on previous
occasions
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Factors affecting immunization and severity
Amount of Antigen ( amount of fetal RBCs)
Host factors .. Integrity of Maternal
Immune Sys
Strength of the antigen ... antigenicity
Influence of ABO group
ABO-incompatible Rh- positive cells will be
hemolysed before Rh antigen can be recognized by
the mothers immune system
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Management of Sensitized Pregnancy
Sensitized Rh Negative mothers
Check quantitative antibodies level _at_ 1st
visit Recheck the level every 2 weeks Serial
U/S Scan monitoring every 2 weeks If antibodies
level continuo at the same level and no
fetal compromise deliver at term
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Management of Sensitized Pregnancy
Sensitized Rh Negative mothers
If antibodies level start to increase Arrange
for amniocenteses Spectrophotometer to study
the optical density of the amniotic fluid
( i.e. bilirubin level which reflect RBCs
haemolysis ) U/S Scan evaluation of the fetal
will beings Use LILY s Curve to determine the
fetal condition
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Ultrasound scan (USS)
Help in fetal monitoring and timing of first
intervention if anti-D level is 10 IU/mL USS
can detect ... Fetal Skin and scalp edema,
... Fetal Ascites, ... Fetal Pericardial or
pleural effusion .. Polyhydramnios .. Fetal
hepatosplenomegaly .. Fetal Cardiomegaly ..
Placental hypertrophy and enlargements ..
Abnormal fetal posture (Buddha stance)
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U/S Scan
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U/S Scan
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U/S Scan
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MRI
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Amniocentesis
Amniocentesis Is an Indirect method to measure
the degree of haemolysis of the fetal red blood
cells by measuring the Concentration of bilirubin
in the amniotic fluid.
Amniotic fluid sample taken and sent for
Spectrophotometer
Where optic density of the fluid changes
according to the amount of the bilirubin
concentration
Increasing of the OD as pregnancy advance shows
worsening of the fetal hemolytic disease
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Amniocentesis
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1.2
1
0.8
0.4
0.1
100
200
450
300
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Lileys chart
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Lileys chart
Zone III
Zone II
Zone I
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Management of Sensitized Pregnancy
Term pregnancy ( mild or Severely affected )
Deliver
Suitability of the place and its facility
Experience of the team
Type of Delivery
Medication
Photo therapy
Extra uterine Blood exchange
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Preterm fetus with Zone I in ..
Cordocentesis blood sample Hb gt 10g/dl No
U / S Scan evidence of Hydropic changes
Consider conservative management with regular
follow up of fetal and maternal conditions till
the fetal lung maturity is assured . Then deliver
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Daily maternal clinical assessments
Fetal Movements Chart
Daily C T G
Serial U / S Scan for fetal growth and amniotic
fluid
Biophysical Profile
Regular cheek of the amniotic fluid bilirubin
level by repeated amniocentesis every 2 weeks
until the lung maturity reached
Regular cheek of the fetal Hb and Hct values if
the facilities available
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Management of Sensitized Pregnancy
Preterm fetus with
Zone II or III
Cordocentesis blood sample Hb less than 10g/dl
Ultrasound evidence of Hydropic changes Consider
Transfer to suitable place
Intra uterine therapy
Delivery extra uterine mang.
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Management of Sensitized Pregnancy
Dexamethazone to enhance lung maturity
Clinical assessments C T G U / S Scan B P P
Consider repeating the intrauterine blood
transfusion
Lung maturity .. If certain deliver
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Management of Sensitized Pregnancy
Intra uterine therapy
Intra peritoneal blood transfusion
Through the umbilical vein Cordocentesis
80 of packed cell o rhesus negative Blood
Cross matched against maternal blood group
Free of infection
Fresh
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Thank you all
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References

• Background information
• Contreras M. The prevention of Rh hemolytic
  disease of the newborn - general background. BJOG
  1998105, s187-10
• Lee D. Preventing RhD hemolytic disease of the
  newborn. 1998 3161611
• NSW Health Rh D Immunoglobulin Policy Directive
  avail at http//www.health.nsw.gov.au/policies/pd/
  2006/pdf/PD2006_074.pdf accessed 1 Nov 2008
• ARCBS Guidelines for the use of Rh (D)
  Immunoglobulin (Anti-D), available at
  http//manual.transfusion.com.au/Pregnancy-and-Ant
  i-D/
• Anti-D mechanism of action, kinetics
• Kumpel BM. On the immunologic basis of Rh immune
  globulin (anti-D) prophylaxis. Transfusion 2006
  461652-1656
• MacKenzie IZ, Roseman F, Findlay J, Thompson K,
  Jackson E, Scott J, Reed M. The kinetics of
  routine antenatal prophylactic intramuscular
  injections of polyclonal anti-D immunoglobulin.
  BJOG. 2006 Jan113(1)97-101.
• CSL Bioplasma Rh(D) Immunoglobulin VF Product
  Information available at http//www.csl.com.au/do
  cs/603/830/CT36600198E.pdf accessed 1 Nov 2008
• Bichler J, Schöndorfer G, Pabst G, Andresen I.
  Pharmacokinetics of anti-D IgG in pregnant
  RhD-negative women. BJOG. 2003 Jan110(1)39-45.

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References contd

• Serological testing
• de Silva PM, Knight RC. Serological testing
  during pregnancy in women given routine antenatal
  anti-D Ig prophylaxis. Transf Med. 1997
  Dec7(4)323-4.
• Management of alloimmunization
• Moise KJ. Red blood cell alloimmunization in
  pregnancy. Semin Hematol 2005 42169 178
• Controversies
• Jabara S, Barnhart KT. Is Rh immune globulin
  needed in early first-trimester abortion? A
  review. AmJObGyn 2003 188 623-7
• Weinberg L. Use of anti-D immunoglobulin in the
  treatment of threatened miscarriage in the
  accident and emergency department. EmergMed J
  2001 18444-447
• Hannafin B, Lovecchio F, Blackburn P. Do
  Rh-negative women with first trimester
  spontaneous abortions need Rh immune globulin?
  AmJEmergMed 2006 24487-489
• Auguston B, Fong EA, Grey DE, Davies JI, Erber
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  dose? MJA 2006 184 (12) 611-613

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Cordocentesis
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Fetoscopy
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The main and most frequent sensitizing event is
child birth (about 86 of sensitized cases),
but fetal blood may pass into the maternal
circulation earlier during the pregnancy (about
14 of sensitized cases)1. Sensitizing events
during pregnancy include miscarriage, therapeutic
abortion, amniocentesis, ectopic pregnancy,
abdominal trauma and external cephalic version.
78
If no prevention measures were taken during
antenatal period
The first pregnancy with a Rhesus positive baby
is significant for a rhesus negative woman
because she can be sensitized to the Rh positive
antigen. about 13 of Rhesus negative mothers are
sensitized by their first pregnancy with a rhesus
positive baby.
about 5 of the second Rhesus positive infants of
Rhesus negative woman, would result in still
births or extremely sick babies and many babies
who managed to survive would be severely ill
By using anti-RhD immunoglobulin (Rho(D) Immune
Globulin) the incidence is massively reduced .
79
Rh disease sensitization is about 10 times less
likely to occur if the fetus is ABO incompatible
with the mother than if the mother and fetus are
ABO compatible.