(P) Rh BGS Flashcards
1
Q
- most important blood group system after ABO
in transfusion medicine.
*Critical component of pre-transfusion and prenatal testing
A
Rh BGS
2
Q
Who described a hemolytic transfusion reaction in 1939 in an OB patient that led to the discovery that the fetus and the father possessed a common factor that the mother lacked
A
Levine and Stetson
3
Q
described an
antibody made by guinea pigs and rabbits when they
were transfused with rhesus macaque monkey RBCs
Consequently, these guinea pigs and rabbits developed
antibodies which react or agglutinated 85% of human
RBCs and was named anti-Rh
They postulated that the antibody that was identified to
the previously mentioned OB patient was the same
antibody produced by the guinea pigs against the rhesus
macaque monkey RBCs.
A
Landsteiner and Wiener
4
Q
what was the name of the antibody that Landsteiner and Wiener discovered?
A
anti-Rh
5
Q
- What was the name for the human produced antibody
- What was the new name for the animals’ antibody
A
- Rh
- anti-LW
6
Q
- after A and B, is the most important RBC
antigen in transfusion practice
*an immune antibody, which is produced
in response to the exposure to the foreign antigen, occurs through blood transfusion or
pregnancy
- antigen with the greatest immunogenecity
A
D antigen
7
Q
detection of Rh status is performed (together / separately) from ABO typing
A
together
(ABO-Rh typing)
8
Q
how many percent of D negative individuals who receive a single unit of D positive blood can be expected to develop immune anti-D
A
> 80%
9
Q
__________ is clinically significant as it can produce
hemolytic transfusion reaction (HTR) and hemolytic
disease of the newborn (HDN )
A
anti-D
10
Q
what type of red cells must be transfused for individuals that has present D negative red cells?
A
D negative red cells also
11
Q
What happens when a Rh-negative person is exposed to less than 0.1 ml of Rh positive RBC
A
antibody production
12
Q
RH BGS BASICS
- Indicates that the red blood
cells lack the D antigen. - ndicates that an individual’s
red blood cells possess one
particular Rh antigen, the D
antigen.
A
- Rh negative
- Rh positive
13
Q
the following can be found on which chromosome?
- ABO BGS
- Rh BGS
- RHAG
A
- chromosome 9
- chromosome 1
- chromosome 6
14
Q
INHERITANCE: MOLECULAR GENETICS OF RH
a. RHD
b. RHCE
c. both
d. neither
- Codes for the presence or absence of the RhD protein
- Gene product: RhCe, RhcE, Rhce, or RhCE
- Gene product: RhD protein
- It is inherited in a codominant manner
- Non-glycosylated
A
- a
- b
- a
- c
- c
15
Q
Where do Rh antigens reside?
A
Transmembrane proteins
16
Q
INHERITANCE: MOLECULAR GENETICS OF RH
a. RHD
b. RHCE
c. both
d. neither
- Glycosylated
- composed of 416 amino acids
- traverses the cell membrane 16 times
A
- d (non-glycosylated)
- c
- d (12 times)
17
Q
Amino acid position
a. 103 AA
b. 112 AA
c. 226 AA
- determines C or c expression
- differentiates E from e
A
- a
- c
18
Q
the following are true of Rh function except:
a. found exclusively on red blood cells
b. maintains structural integrity of RBCs
c. CO2 transporters
d. lactic acid transporters
A
d
19
Q
familiarize the 4 nomenclatures
- Fisher-Race: DCE terminology
- Wiener: Rh-hr terminology
- Rosenfield & Coworkers: alpha/numeric terminology
- International Society of Blood Transfusion (ISBT):
numeric terminology
A
- Fisher-Race: DCE terminology
- Wiener: Rh-hr terminology
- Rosenfield & Coworkers: alpha/numeric terminology
- International Society of Blood Transfusion (ISBT):
numeric terminology
20
Q
NOMENCLATURE OF THE RH SYSTEM
- based on the theory that the antigen of the system were produced by three closely linked set of alleles, each gene was responsible for producing a product
- based on genetic mechaism
- three loci carry the RH genes whichare closely linked that they never seperate but are passed down from generation to generation as a unit or gene complex
A
Fisher-Race : DCE terminology
21
Q
this represents the absence of D in the Fisher-race nomenclature
A
d
22
Q
what are the five common antigens in the Fisher-Race nomenclature
A
D,C,c,E,e
23
Q
NOMENCLATURE OF THE RH SYSTEM
- Rh gene: 2 genes, one on each chromosome pair
- Rh gene produces a structure on the RBC called an
agglutinogen, instead of a set of gene complex - ___________believed there was one gene responsible for defining
Rh that produced an agglutinogen comprising of three Rh
factors/ blood factors
A
WIENER: Rh-Hr TERMINOLOGY
24
Q
What theory is this:
antibody will recognize each factor within the agglutinogen
A
Wiener’s agglutinogen theory
25
familiarize the 8 agglutinogens of the Wiener agglutinogen theory
R0, R1, R2, RZ, r, r’, r’’, and rY
26
WIENER NOMENCLATURE RULES
1. The uppercase R denotes the (presence/absence) of the D antigen.
2. The lowercase r indicates the (presence/absence) of D antigen.
1. presence
2. absence
27
* a nomenclature based only on serologic
(agglutination) reactions.
* Wherever it’s tested positive, you will write the numeric
number of that antigen.
* Each antigen is assigned with a numeric number
* has no genetic assumptions or basis
ROSENFIELD AND COWORKERS: ALPHANUMERIC
TERMINOLOGY
28
what signifies the absence of the antigen in the ROSENFIELD AND COWORKERS: ALPHANUMERIC
TERMINOLOGY
minus sign (-)
29
* International organization created to standardize blood
group system nomenclature.
* Numeric terminology
* The ISBT adopted a six-digit number for each
authenticated antigen belonging to a blood group system.
INTERNATIONAL SOCIETY OF BLOOD
TRANSFUSION COMMITTEE
30
ISBT terminology
what number was assigned to the Rh BGS
004
31
Provide the numeric equivalent of the following antigens:
1. D
2. C
3. E
4. c
5. e
1. 004001
2. 004002
3. 004003
4. 004004
5. 004005
32
list down all of the Rh antigens from most immunogenic to the least immunogenic
D > c > E > C > e
Rosenfield code: 1 4 3 2 5 (D=1, c= 4, E= 3, C=2, e= 5)
33
* Previously known as Du type or Du variant
* Modification of Rh gene which result to a weak expression of
D antigen
* Result in differences from normal D expression
WEAK – D
34
What are the three mechanisms for weak D
1. Genetic : quantitative changes due to fewer D antigen sites
2. Position Effect: C in trans to D
3. Partial D or D mosaic
35
Which mechanism for weak D?
* results in lowered densities of D antigens on RBC membranes, gene codes for less D antigen
* weakened expression
Genetic
36
Which mechanism for weak D?
If the big C is at the trans position, meaning, on the
opposite side of the haplotype, it will then weaken the
expression of the D antigen.
Position effect
37
C and D antigen arrangement causes ________________
which results in weakening or suppression of D
expression
steric hindrance
38
Which mechanism for weak D?
* when one or more D epitopes within the
entire D protein is either missing or altered
* absence of a portion or portions of the total material that comprises the D antigen
Mosaic D / Partial D
39
What is formed when a person with Partial D or D mosaic is transfused with D positive red cells?
anti-D alloantibody
40
T or F
Not all D positive cells react equally well with anti-D.
T
41
T or F
RBCs not immediately agglutinated by anti-D must be tested for weak D
T
42
Significance of weak D
Transfusing weak D to a D negative person, what may happen?
The D negative person will make anti-D
43
Significance of weak D
A person with anti-D will have what type of reaction if they were to be transfused with blood that has weak D?
severe hemolytic transfusion reaction (HTR)
44
Routine or not?
1. Weak D testing on patients
2. Blood donors
3. Transfusing patients with D negative blood
1. not routine
2. not routine
3. routine (standard practice)
45
What is a key characteristic of high protein anti-D reagents?
A) They do not require a diluent control
B) They are used only for the slide test
C) They may cause false positives with unwashed red blood cells
D) They cannot be used for weak D testing
C) They may cause false positives with unwashed red blood cells
46
Why is a diluent control required for high protein anti-D reagents?
A) To prevent false negatives
B) To detect false positives caused by autoagglutinins or abnormal serum proteins
C) To enhance agglutination
D) To increase specificity
B) To detect false positives caused by autoagglutinins or abnormal serum proteins
47
IgM anti-D (low protein/saline) reagents are mainly used for:
A) Individuals who show false positives with high protein anti-D
B) Enhancing agglutination in weak D tests
C) Increasing reaction strength at AHG phase
D) Routine ABO testing
A) Individuals who show false positives with high protein anti-D
48
Why is IgM anti-D scarce?
A) It has a short shelf life
B) It is difficult to obtain raw material
C) It requires a special incubation step
D) It is not widely used in modern blood banking
B) It is difficult to obtain raw material
49
What is a limitation of IgM anti-D reagents?
A) They require a negative control for all tests
B) They cannot be used for weak D or slide testing
C) They react only at AHG phase
D) They cause false positives with all Rh-negative samples
B) They cannot be used for weak D or slide testing
50
What is the purpose of chemically modifying IgG anti-D?
A) To convert it into an IgM-like antibody
B) To weaken its reactivity
C) To increase flexibility and span distance
D) To decrease its reaction strength
C) To increase flexibility and span distance
51
Chemically modified anti-D reagents are advantageous because:
A) They require a negative control for all tests
B) They show stronger reactivity than IgM reagents
C) They can only be used in the tube test
D) They are more likely to cause false positives
B) They show stronger reactivity than IgM reagents
52
Which statement about monoclonal anti-D is TRUE?
A) It is prepared only from IgM antibodies
B) It is rarely used in blood banking
C) It is a combination of monoclonal IgM and polyclonal IgG
D) It cannot be used for weak D testing
C) It is a combination of monoclonal IgM and polyclonal IgG
53
Which reagent type reacts at IS for immediate spin testing?
A) High protein anti-D
B) IgM anti-D
C) Monoclonal anti-D (IgM component)
D) Both B and C
D) Both B and C
54
In monoclonal anti-D reagents, why is polyclonal IgG included?
A) To react at AHG phase for weak D testing
B) To prevent false positives
C) To eliminate the need for controls
D) To increase its specificity for ABO testing
A) To react at AHG phase for weak D testing
55
___________ are epitopes which occur due to
presence of two Rh genes on the same HAPLOTYPE , cis
position
compound antigens
56
*Combination (COMPOUND) Ag
* When c & e are in cis, eg., dce/DCe
* Anti-f may be helpful in phenotyping , may cause TR, HDFN
* Give antigen negative c and e
f (ce)
57
○ No Rh antigens, lack Rh antigens on their RBC
○ Designated as - - -/- - -
Rh null
58
Two types of Rh null based on genetic mechanism
a. regulator-normal RHCE and RHD; abnormal RHAG
b. Amorphic-normal RHAG; abnormal
RHCE and RHD
59
matching type
a. regulator
b. amorphic
1. normal RHCE and RHD; abnormal RHAG
2. normal RHAG; abnormal
RHCE and RHD
3. Mutation on the RHCE and
deletion on the RHD gene
4. No RhAG protein for
expression, no RhD and
RhCE (RBCs)
5. There are antigens produced
but no expressor. There will
be no antigen expressed in
RBC
1. a
2. b
3. b
4. a
5. a
60
○ hemolytic anemia, reticulocytosis, stomatocytosis,
decrease in Hgb and Hct, increase in Hgb F,
decrease serum haptoglobin, elevated bilirubin
○ Rh null transfuse with Rh null blood
Rh null syndrome
61
○ Mutations in the RHAG gene resulting to altered
RhAG protein also with the normal Rh antigens -
Weakened expression of normal Rh and LW
antigens
Rh mod
62
○ Increase D antigen (exalted D)
○ No C/c and E/e antigen - Designated as D- -/ D—
○ Normal RHD genes and hybrid RHCE-RHD-RHCE
○ Antibody: anti-Rh17 or anti-Hr0
Rh deleted
63
Rh Antibodies are:
Most are _____and reacts optimally at _____ or after
antiglobulin testing
IgG, 37° C
64
T or F
Rh antibodies bind complement, they have no capability to agglutinate the RBCs
F (They do not bind complement)
65
Rh Antibodies
RBC destruction is (intravascular / extravascular), causing delayed HTR
EXTRAVASCULAR
66
Rh antibodies
○ Rabbits immunize with Rhesus monkey blood
○ Agglutinates Rh+ and Rh- cells except Rh null
cells (do not contain any of Rh antigen)
ANTI-LW / ANTI-Landsteiner and Wiener
67
which IgGs can cross the placenta, causing HDFN
IgG1 and IgG 3
68
a. false positive b.false negative
1. Spontaneous agglutination
2. Contaminated reagents
3. Use of wrong anti-serum
4. Failure to add anti serum to test
5. Use of wrong typing sera
1. a
2. a
3. b
4. b
5. a
69
a. false positive b.false negative
1. Incorrect cell suspension
2. Incorrect anti-serum to cell ratio
3. Using anti-sera in a test method
other than that required by the
manufacturer
4. Vigorous shaking
5. over centrifuged
1. b
2. b
3. a
4. b
5. a
70
a. false positive b.false negative
1. Reagent deterioration
2. Failure of anti-serum to react with
variant Ag
3. Anti-serum in which the Ab detected
against compound Ag
4. under centrifugation
b for all numbers
71
Which Rh antigen is the most immunogenic and often responsible for transfusion reactions?
A) A antigen
B) B antigen
C) D antigen
D) O antigen
D antigen
72
What is a major consequence of Rh incompatibility in transfusion reactions?
A) Increased platelet count
B) Extravasacular destruction of RBCs
C) Increased hemoglobin levels
D) Decreased antibody production
B) Extravasacular destruction of RBCs
73
Which of the following is NOT a sign or symptom of Rh transfusion reaction?
A) Unexpected fever
B) Mild bilirubin elevation
C) Increase in hemoglobin
D) Decrease in haptoglobin
C) Increase in hemoglobin
74
What does a positive Direct Antiglobulin Test (DAT) indicate?
A) Dehydration
B) Sensitization of RBCs with antibodies in vivo
C) Increased platelet adhesion
D) Decreased bilirubin levels
B) Sensitization of RBCs with antibodies in vivo
75
Why does Hemolytic Disease of the Newborn (HDFN) occur?
A) The father is Rh (-) and the mother is Rh (+)
B) The fetus is Rh (-) and the mother is Rh (-)
C) The fetus is Rh (+) and the mother is Rh (-)
D) The father is Rh (-) and the baby is Rh (-)
C) The fetus is Rh (+) and the mother is Rh (-)
76
When should Rh immune globulin (Rhogam) be administered to prevent HDFN?
A) Only after delivery
B) 72 hours after delivery
C) During labor
D) After every transfusion
B) 72 hours after delivery
77
What is the primary function of Rhogam?
A) To destroy maternal antibodies against Rh antigens
B) To prevent the mother from producing antibodies against Rh (+) blood
C) To increase maternal hemoglobin levels
D) To increase fetal bilirubin clearance
B) To prevent the mother from producing antibodies against Rh (+) blood
78
When should the fulldose of anti-D be administered?
> 12 weeks of gestation
79
How many micrograms is one full does of anti-D?
300 ug
80
When should be the mini-dose / micro dose of anti-D be administered?
12 weeks of gestation
81
how many ug of anti-D is a mini dose / micro dose of anti-D?
50 ug
