03+Rh+Blood+Grp
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1
What is the Rh Blood Group System? and what does it refer to?
- is one of the most important blood group systems in transfusion medicine, second only to the ABO system. It plays a crucial role in blood transfusions, organ transplantation, and pregnancy
- presence or absence of the D antigen found on the RBC.
- presence or absence of the D antigen found on the RBC.
2
Are there "naturally occuring" antibodies in Rh blood group system?
NO, there are no "naturally occurring" antibodies.
3
What are the 5 different antigen encountered in routine BB testing?
D, C, E, c & e antigens
4
Out of the 5 different antigens, which is the most routinely tested and is the most immunogenic amount ALL blood group antigens?
D antigens
5
So when are C, E, c, and e antigens are dealt with?
When a corresponding antibody is detected and identified in the patient's serum (prior to transfusion).
6
In total, how many antigens are there on the RBCs?
49 antigens; there are variants, rare antigens, and genes.
7
How is the Rh blood group system inherited?
-Mendelain inheritance patterns;
-parental inheritance in "linked fashion" as Haplotype (RHD & RHCE) ->> refers to a specific combination of D, C/c, and E/e antigens inherited together.
-parental inheritance in "linked fashion" as Haplotype (RHD & RHCE) ->> refers to a specific combination of D, C/c, and E/e antigens inherited together.
8
What gene encodes for the D antigen?
RHD gene
9
What gene encodes for the C/ c, E/ e antigen?
RHCE gene
10
Besides RHD & RHCE, what gene MUST be present for successful expresion of the Rh antigens? and what chromosome is it located in?
RHAG (co-receptor gene); Chromosome 6
11
What is immunogenicity?
how strong an antigen is going to illicit an anitbody response
12
What is the immunogenicity order of Rh antigens?
D > c > E > C >e
13
What are the 4 types of nomenclatures used to designate each Rh antigen along with the appropriate theory?
- Fisher-Race
- Wiener
- Rosenfield
- ISBT
- Wiener
- Rosenfield
- ISBT
14
Which is the rare type of nomenclature? and where can it be found?
Rosenfield; hidden code in ISBT
15
Where can ISBT nomenclature be found?
label on blood components
16
Which nomenclature is known by BB and staff?
Fisher-Race
Wiener
Wiener
17
What is the Fisher-race nomenclatures? and what does it represent?
- one of the main ways we describe Rh antigens in blood banking, especially in the U.S;
- it represents the Rh antigens using the letters: D, C, c, E, e
- it represents the Rh antigens using the letters: D, C, c, E, e
18
True/false: 3 separate, closely linked genes that produce the Rh antigens (D, C, E, c, e).
TRUE :)
19
When are antibodies formed?
exposure to the antigen that is NOT present in the patient.
20
What nomenclature is this?
Fisher-Race
21
What does the presence of D gene produce?
Produces D antigen aka Rh +
22
What does the presence of little d gene produce?
"d" antigen not produced aka Rh -
23
What do Cc genes produce?
C/c antigen
24
What does the Ee genes produce?
E/e antigen
25
What is the gene frequency of Rh antigens: D?
85%
26
What is the gene frequency of Rh antigens: d?
15%
27
What is the gene frequency of Rh antigens: C?
70%
28
What is the gene frequency of Rh antigens: E?
30%
29
What is the gene frequency of Rh antigens: c?
80%
30
What is the gene frequency of Rh antigens: e?
98%
31
What is the Wiener nomenclature?
The Wiener nomenclature is another way to describe the Rh blood group system, and it goes hand-in-hand with the Fisher-Race system — they both describe the same antigens, but in different formats.
32
How is the Wiener nomenclature written?
Wiener uses a single letter + number to represent a haplotype (a set of Rh genes inherited together)
33
What does "one locus encodes for", in the Wiener nomenclature?
Production of an "agglutinogen" which has 3 factors (antigen/epitopes).
34
What nomenclature is this?
Wiener's
35
What are the Fisher-Race Antigens for
R0
R1
R2
Rz?
R0
R1
R2
Rz?
R0 - Dce
R1 - DCe
R2 - DcE
Rz - DCE
R1 - DCe
R2 - DcE
Rz - DCE
36
What are the Fisher-Race antigens for
r
r'
r''
ry?
r
r'
r''
ry?
r - dce
r' - dCe
r'' - dcE
ry - dCE
r' - dCe
r'' - dcE
ry - dCE
37
Are there any genetic assumptions made in rosenfield?
NO
38
How is the numerical system set up for Rosenfield?
If a number is listed, the antigen is present e.g., Rh: 1 = D antigen.
If a number is listed with a "-" (minus sign), the antigen is not present.
If not listed, the antigen was not determined.
If a number is listed with a "-" (minus sign), the antigen is not present.
If not listed, the antigen was not determined.
39
what does the rosenfield adapt well to?
Computer entry
40
What are the antigens designated by number in Rosenfield nomenclature?
Rh1: D
Rh2: C
Rh3: E
Rh4: c
Rh5: e
Rh2: C
Rh3: E
Rh4: c
Rh5: e
41
How is the Rosenfield nomenclature written for D+, C+, E-, c+, e+?
Rh: 1, 2, -3, 4, 5
42
What is the Fisher-Race genotype for Weiner (R1r)?
R1r = DCe/dce
43
What is the Fisher-Race genotype for Weiner (R1R1)?
R1R1 = DCe/DCe
44
What is the Fisher-Race genotype for Weiner (rr)?
rr = dce/ dce
45
What is the Fisher-Race genotype for Weiner (R1R2)?
DCe/DcE
46
What is the Fisher-Race genotype for Weiner (R2r)?
R2r = DcE/dce
47
What is the Fisher-Race genotype for Weiner (R2R2)?
R2R2 = DcE/DcE
48
What is the Fisher-Race genotype for Weiner (r'r)?
r'r = dCe/dce
49
What is the Fisher-Race genotype for Weiner (r'r')?
dCe/dCe
50
What is the Fisher-Race genotype for Weiner (r"r)?
dcE/dce
51
What is the Fisher-Race genotype for Weiner (r"r")?
dcE/dcE
52
What is the Fisher-Race genotype for Weiner (R0r)?
Dce/dce
53
What is the Fisher-Race genotype for Weiner (R0R0)?
Dce/Dce
54
What is the Fisher-Race genotype for Weiner (ryr)?
dCE/dce
55
Which are the rarer genotypes?
R1r
R1R1
rr
R1R2
R2r
R2R2
or
r'r
r'r'
r"r
r"r"
R0r
R0R0
ryr
R1r
R1R1
rr
R1R2
R2r
R2R2
or
r'r
r'r'
r"r
r"r"
R0r
R0R0
ryr
second group
56
What does ISBT stand for?
International Society of Blood Transfusion
57
How is the ISBT structured? what's an example?
6-digit number for each antigen specificity, e.g., 004001 for Rho
58
What do the first 3 digits indicate?
ex 1: 004
ex 2: 001
ex 1: 004
ex 2: 001
ex 1: 004 = Rh
ex 2: 001 = ABO
ex 2: 001 = ABO
59
What do the last 3 digits indicate?
ex: 004001
ex 2: 001001
ex: 004001
ex 2: 001001
blood group antigen specificity
ex: 004001 = D antigen of the Rh system
ex 2: 001001 = A antigen of the ABO system
ex: 004001 = D antigen of the Rh system
ex 2: 001001 = A antigen of the ABO system
60
For recording of phenotypes, what does the ISBT system adopt?
adopts the Rosenfield approach
61
What role does the Rh antigens play?
an IMPORTANT functional role on the RBC membrane, i.e., integrity & intracellular cation transport
62
The lack of some (or missing) Rh antigen is known as?
"Deletion" for the missing antigen
63
The lack of ALL Rh system antigens is called? and what does it cause?
"Rh null" ; causes a membrane abnormality that shortens the normal RBC survival
64
What are the possibilties for
Mom (R1R2) + Father (rr")
DCe/DcE + dce/dcE
?
Mom (R1R2) + Father (rr")
DCe/DcE + dce/dcE
?
R1r, R2r, R1r", R2r"
65
What are Rh phenotyping used for? (5 reasons)
- Parental or paternity testing
- Predicting HDFN (Hemolytic Disease of the Fetus/Newborn)
- Confirmation of Rh Ab specificity
- Finding compatible blood for transfusion recipients with Rh Abs
- Used published frequencies & subject info to help determine possible genotype (s) & availability of antigen negative blood
- Predicting HDFN (Hemolytic Disease of the Fetus/Newborn)
- Confirmation of Rh Ab specificity
- Finding compatible blood for transfusion recipients with Rh Abs
- Used published frequencies & subject info to help determine possible genotype (s) & availability of antigen negative blood
66
In order for the body to create antibodies, do you have to be antigen pos/neg?
ANTIGEN negative
67
What is the %RH0 (D) pos by population?
99-100% Japanese, Chinese, American Indians, Melanesians
95% Black Africans
85% Europeans, Caucasian North Americans
60-75% Basques
95% Black Africans
85% Europeans, Caucasian North Americans
60-75% Basques
68
Before diagnosing negative D, what should you do? why?
You have to do further tests!
Most D antigen positive cells will hemagglutnate at the IS test phase using normal Anti-D antisera.
However, the weak D antigen expression requires taking the initial testing further.
Most D antigen positive cells will hemagglutnate at the IS test phase using normal Anti-D antisera.
However, the weak D antigen expression requires taking the initial testing further.
69
What should be followed after IS test phase to demonstrate hemagglutination to the weak D positive cells?
Testing continutes to the 37oC incubation phase followed by the AHG testing phase.
70
What are the 3 mechanisms/categories of the weak D antigen expression?
1. Quantitative (genetic)
2. Position Effect
3. Partial/Mosaic D antigen (missing parts)
2. Position Effect
3. Partial/Mosaic D antigen (missing parts)
71
What are quantitative weak D antigens?
- RHD gene codes for weak expression of D antigen
- D antigen is complete (all epitopes of D antigen are present), there are just fewer D antigen sites on RBC.
- Normal D sites - 15,000 - 33,000 D sites/cell
- Weak D - 70-5200 D sites/cell
- D antigen is complete (all epitopes of D antigen are present), there are just fewer D antigen sites on RBC.
- Normal D sites - 15,000 - 33,000 D sites/cell
- Weak D - 70-5200 D sites/cell
72
What is the weak D test?
An antiglobulin test (AHG) that demonstrates IgG antibody on the red cell.
73
What does it mean if the Rh control is positive?
This indicates that the cells have IgG on them before testing, making the test invalid or unable to be interpreted.
74
What is weak D? and what test does it require for its detection?
weak form of the D antigen that requires the IAT for its detection
75
What is the weak D caused by? (Genetically) WHAT IS THIS CALLED?
Weak D caused by C inherited in trans as opposed to cis
POSITION EFFECT
POSITION EFFECT
76
According to the Partial/ Mosaic theory, what does the weak D antigen cause during transfusions?
If the patient is transfused with D positive red cells, they may develop an anti-D alloantibody* to the part of the antigen (epitope) that is missing.
77
What is the partial/ mosaic theory of the weak D?
D antigen is mosaic, possesses many parts.
1 or more parts are missing - making it weak
1 or more parts are missing - making it weak
78
Why does C in the trans position to D cause a weak D?
C creates a limiting effect on the expression of D resulting in a weak D expression.
79
What does it mean when there are deletions of Cc and / or Ee (D-- or D··).? What antibody do they contain?
Represent partial locus deletions; seen in people with hybrid in which the Rhce protein is replaced with RhD;
anti-Rh17 or anti-Hr0.
anti-Rh17 or anti-Hr0.
80
What is an "exalted D"? and when is it commonly seen?
unusually strong D antigen expression; usually seen in consanguineous marriages/ situations
81
How are CIS-product antigens formed?
when 2 genes are inherited on the same chromosome (CIS position)
82
What are examples of CIS antigen products for Rh?
Rh 6 (cis "ce" or "f"): c & e inherited as a haplotype (cde or cDe)
Rh 7 (cis "Ce" or "rhi") C & e inherited as haplotype
Rh 27 (cis cE)
Rh 22 (cis CE)
Rh 7 (cis "Ce" or "rhi") C & e inherited as haplotype
Rh 27 (cis cE)
Rh 22 (cis CE)
83
What are 2 examples of Rh compound antigens?
Cw
f(ce)
f(ce)
84
Is Cw the same thing as C & c?
No, Cw is not allelic to C & c
85
In what phenotype is C & Cw usually seen together?
R1wR1 phenotype
86
What is the % of Cw seen in Caucasians, what about Afro-americans?
2% - Caucasians
Very rare - afro-americans
Very rare - afro-americans
87
What does dosage mean?
variation in antigen expression due to the number of alleles present.
88
What is naturally occuring in Anti-Cw and what does it show?
Anti-Cw; shows dosage
89
When is f(ce) expressed? what is an example?
When c & e are in cis position; e.g., dce or Dce haplotype
90
Is f(ce) a compound antigen?
YES
91
What may be helpful with Anti-f antisera?
phenotyping
92
When is rhi (Ce) expressed?
When C & e are in cis position on the RhCe protein
93
Is Ce a compound antigen? AND what helps in phenotyping?
YES!; antibodies are helpful in phenotyping.
94
Which antigen is COMMONLY SEEN in Rh+ people, besides D and C-positive?
G
95
What is G antigen always found with?
D- & C- positive RBCs
96
What does anti-G appears to bind to? AND what does it look like is also present?
D, C, & G;
Anti-C & Anti-D are also present , but cannot be separated.
Anti-C & Anti-D are also present , but cannot be separated.
97
Why might an Rh-negative patient exposed only to the C antigen develop anti-G instead of (or in addition to) anti-C?
Because anti-G mimics both anti-D and anti-C reactivity and can be produced after exposure to C antigen alone, even if the patient was not exposed to D.
98
Do deleted Rh phenotypes exist? what does it mean? What might be the cause?
Specifically?
Specifically?
YES! It means they lack many Rh antigen and may be caused by the rearrangement of some of the Rh genetic material.
Occurs from replacement of large portions of RHCE gene with normal RHD gene.
Occurs from replacement of large portions of RHCE gene with normal RHD gene.
99
What genotypes will fail to produce some or all Rh CE antigens?
D--, Dc-, Dcw-
100
what are 2 Rh deficiency syndromes? or allelic deletions? what do they mean?
1. Rhmod - weakened expression of Rh antigens
2. Rhnull - no Rh antigens expressed at all
2. Rhnull - no Rh antigens expressed at all
101
What causes the Rhmod syndrome? what the RBC abnormalities are similar to those of what?
Mutation in RHAG gene; similar to those of Rh null
102
Are clinical symptoms severe in Rhmod? and does expression vary per individual?
No they are less severe and rarely remarkable.
Yes, expression does vary per individual.
Yes, expression does vary per individual.
103
What are the 2 genetic mechanisms for Rhnull characteristic?
1. Regulator Type
2. Amorphic Type
2. Amorphic Type
104
Which is more commone Regulator or Amorphic Type?
Regulator
105
What type of mutation is involved in Regulator type? and what does it do?
Mutation in RHAG gene, where no RHAG protein is expressed; it can transmit normal RHD & RHCE genes
106
what type of mutation is involved in Amorphic type? Which gene is normal?
Mutation in each RHCE gene & a deletion in the RHD gene ; RHAG gene is normal
107
How is Wiener "Rhnull" expressed in Fisher Race?
---/---
108
What can be seen in the CBC for Rh null?
Mild hemolytic anemia & reticulocytosis
& increased level of Hgb F
& increased level of Hgb F
109
What happens if normal Rh cells are transfused into a patient with Rhnull? what should this patient only be transfused with?
a potent anti-Rh29 is produced; transfuse only using another Rhnull RBCs.
110
Is Rh typing part of forward or reverse typing?
Forward Typing
111
According to TJC & CAP PT: Rh typing test must what?
be 100% correct/accurate at ALL TIMES!!!
112
How many drops of reagent antisera (blue and yellow) are added to forward typing? how many drops of patient cells are added?
1 drop; 1 drop
113
How many drops of patient serum are added to reverse typing? how many drops of red cell reagent are added?
2 drops; 1 drop
114
what substance should you always add when doing serological testing?
"clear" substance first!!!
115
Adding the cells last in serological testing accomplishes what 3 things?
1. The reagent/serum was added to the test.
2. The test is properly setup for serological testing.
3. A "false" negative test result due to the lack of adding reagent or serum can be avoided.
2. The test is properly setup for serological testing.
3. A "false" negative test result due to the lack of adding reagent or serum can be avoided.