Rh Blood Group System

2. “RHESUS BLOOD GROUP
SYSTEM”
PRESENTED BY:
KAUSAR FAROOQ,
BS MT 3
RD
YEAR 6
TH
SEMESTER.

3. Rhesus blood group systemRhesus blood group system
The Rh blood group system is one of
the most polymorphic and
immunogenic systems known in
humans.
It is the most complex system, with
over 45 antigens.
Discovered in 1940 after work on
Rhesus monkeys.
RH gene located on short arm of
chromosome 1.

4. Rhesus blood group systemRhesus blood group system
First demonstrated by testing human
blood with rabit anti sera against red
cells of Rhesus monkey & classifying
Rh negative & Rh positive.
The genotype is determined by the
inheritance of 3 pairs of closely linked
allelic genes situated in tanderm on
chromosome 9.

5. •1939 Levine and Stetson defined D antigen (Rh
factor)
•1940 Landsteiner and Weiner discovered anti-
Rh (named after Rhesus monkey)
•Agglutinated 85% human RBCs
–15% RBCs did not agglutinate
•The antibody was similar to guinea pig and
rabbit antibodies produced when stimulated
with rhesus monkey RBCs
•Although they were later shown to be different,
the name remained

6. Land Steiner and Wiener reported on an antibody
by guinea pigs and rabbits when they were
transfused with rhesus monkey red cells.
This antibody which agglutinated 85% of human
red cells was named Rh.+
The name Rh was retained for the human produced
antibody
Anti-rhesus formed by the animals was renamed
anti-LW (Landsteiner and Wiener).

7. Rh AntigensRh Antigens
Rh antigens are highly immunogenic, the D antigen is
most potent
 D  c  E  C  e
Highly Rarely
Immunogenic
Exposure to less than 1 ml of Rh positive red cells
can stimulate Ab production in an Rh negative
person.

8. Rh GeneticsRh Genetics
2 closely linked genes control the
expression of ALL Rh antigens
(codominant alleles)
–RHD gene - determines the expression of
the D antigen
–RHCE gene - determines the expression
of the C, c, E, and e antigens

9. RHD gene RHCE gene
Chromosome 1
Proteins

10. Rh NomenclatureRh Nomenclature
There are several different systems of
nomenclature that theorize the inheritance
of the Rh system
–Fisher-Race
–Wiener
–Rosenfield

11. Fisher-Race NomenclatureFisher-Race Nomenclature
CDE terminology
Most commonly used (i.e. WHO)
Developed by Ronald Fisher and Robert
Race of England
They theorized that the Rh antigens are
controlled by a complex of 3 sets of genes
with closely linked loci (i.e. Dce gene
complex codes for D, c, e antigens)

12. Fisher-RaceFisher-Race
D
d
C
c
E
e
3 closely linked
genes
“d” antigen not
produced
Produces D antigen
Produces C/c antigen
Produces E/e antigen

13. Fisher-RaceFisher-Race
There are 8 gene
complexes at the Rh
locus
Fisher-Race uses
DCE as the order
Others alphabetize
the genes as CDE
dceDCE
dcEDce
dCEDcE
dCeDCe

14. Wiener NomenclatureWiener Nomenclature
Rh-Hr terminology
Rarely used, but good for describing phenotype
A single gene at the Rh locus leads to the expression
of the Rh antigens
Each parent contributes 1 Rh gene
8 alleles exist at each gene locus
Each gene controls production of an agglutinogen
composed of three factors (antigens)

15. Wiener TheoryWiener Theory
Single gene at Rh
locus
rh’
hr’
Rh
0
rh”
hr”
Rh
0
D
rh’ C
rh” E
hr’ c
hr” e
5 Major Rh
Factors/Antigens:
(longhand version)
Produces
D antigen
on RBC
Produces C
antigen on
RBC

16. Rosenfield Nomenclature
Antigens are designated by number
–Rh1:D
–Rh2:C
–Rh3:E
–Rh4:c
–Rh5:e
–Example
•D+, C+, E-, c+, e+ is written as
Rh:1,2,-3,4,5

17. Genotype vs. PhenotypeGenotype vs. Phenotype
•The phenotype is the result of the reaction
between the red cells and antisera
•The genotype is the genetic makeup and can
be predicted using the phenotype and by
considering the race of an individual.

18. PositiveR
2
R
2
cDE/cDER
PositiveR
2
rcDE/cde
PositiveR
1
rCDe/cde
PositiveR
1
R
2
CDe/cDE
PositiveR
1
R
1
CDe/CDe
Negativerrcde/cde
Rh(D)
status
Symbol Genotype

19. CcDeR
1
r
Ccerr’
CDER
Z
R
Z
cEerr’’
CdER
2
R
2
cDeR
0
R
0
cDEeR
2
r
cerr
CDeR
1
R
1
CcDEeR
1
R
2
CDERh Phenotype

20. Why is an Rh incompatibility so dangerous Why is an Rh incompatibility so dangerous
when ABO incompatibility is not during when ABO incompatibility is not during
pregnancy?pregnancy?
• Most anti-A or anti-B antibodies are of the
IgM class (large molecules) and these do not
cross the placenta.
•In fact, an Rh−/type O mother carrying an
Rh+/type A, B, or AB foetus is resistant to
sensitisation to the Rh antigen.
•Her anti-A and anti-B antibodies destroy any
foetal cells that enter her blood before they
can elicit anti-Rh antibodies in her.

21. This phenomenon has led to an effective
preventive measure to avoid Rh sensitisation.

Shortly after each birth of an Rh
+
baby, the
mother is given an injection of anti-Rh antibodies
(or Rhogam).
These passively acquired antibodies destroy any
foetal cells that got into her circulation before they
can elicit an active immune response in her.
Rh incompatibility during Rh incompatibility during
pregnancy (cont.)pregnancy (cont.)

22. D TESTING:D TESTING:
•Protocol
–Add Anti-D to “D” tube; Rh control to “C” tube
–Spin, read and record
•If “D” is positive, cells are Rh positive
•If “D” is negative, continue testing
–Add 22% albumin and incubate for 20” at 37
o
C
–Spin, read, and record
–Wash 3 X in saline
–Add AHG, spin, read, and record
–If “D” is positive after heat/albumin or AHG  cells
are weak D positive; if negative, cells are Rh negative;
“C” should always be negative
–Add check cells to neg. tubes; spin, read & record

23. Importance of the Rh systemImportance of the Rh system
After the A and B antigens, the D
antigen is the most important red cell
antigen in blood banking
The D antibody can cause transfusion
reactions and hemolytic disease of the
newborn (HDN)/Erythroblastosis
fetalis

24.  A person with Rh- blood can develop Rh antibodies in the blood
plasma if he or she receives blood from a person with Rh+ blood,
whose Rh antigens can trigger the production of Rh antibodies.
A person with Rh+ blood can receive blood from a
person with Rh- blood without any problems.