MMSC 409 Exam 2 Questions and Verified
Answers
Compare the antibody discovered by Landsteiner and Weiner with the antibody
discovered by Levine and Stetson around 1940. Correct Answer: Levine and
Stetson- discovered Rh blood group, mother gave birth to a stillborn, mother began
to hemorrhage, father and mother same ABO group, gave mother blood from
father-> reaction
Landsteiner/Weiner- discovered D antigen when antibody was created in Rhesus
monkey when exposed to human red cells- 85% human cells were agglutinated
State the five major antigens in the Rh blood group system and their anti-thetical
alleles. Correct Answer: D antigen- no true antithetical allele (D-amorph denotes
absence of D)
C antigen- c is antithetical allele
E antigen- e is antithetical allele
Explain the "d antigen". Correct Answer: Rh is a misnomer- used to describe the red
cell D antigen
Positive is presence of D antigen ~80%
Negative is absence of D antigen ~15%
d is an amorph (no detectable antigen)- no anti-D antibody
Explain the Fisher-Race theory (DCE nomenclature) of inheritance of Rh blood
group system. Correct Answer: 3 closely linked sets of allelic genes- Dd, Cc, Ee
Move as a unit have one or the other codominant
d is lack of D
,What are the eight combinations of the antigens for Fisher-Race? Correct Answer:
Dce
DCE
DcE
DCe
dce
dCE
dcE
dCe
cde/cde antibodies Correct Answer: anti-D, anti-C, anti-E
Define phenotyping. Correct Answer: identification of antigens
cannot always determine genotype- molecular testing determine this
the following used: anti-D, anti-C, anti-c, anti-E, anti-e
Explain the Weiner theory of inheritance of the Rh blood group system. Correct
Answer: 1 gene results in production of agglutinogen which is composed of blood
factors
current loci theory: two loci; Rh genes are located on chromosome 1 and very
closely linked:
loci 1 encodes presence/absence of D
loci 2 encodes presence/absence of Ce, cE, ce, or CE
, Discuss Rosenfield's influence on the Rh nomenclature. Correct Answer: system
indicates the presence or absence of antigen on the cell; provides a straightforward
description of cell phenotype
minus sign= absence of antigen
if not typed for, it should not appear in the sequence
Justify why the D antigen is the most important antigen next to the ABO blood
group system. Correct Answer: most immunogenic- upon exposure to D antigen
through transfusion or pregnancy, 80-90% D neg will make anti-D
present on RBC before birth-prior to RhIg it was the most frequent cause of HDFN
(mom make anti-D antibody and can hurt baby if it has antigen)
Discuss the importance of antigen frequencies when searching for compatible blood
for a patient with an antibody. Correct Answer: ID of antigens cannot always
determine genotype (D doesnt have a partner-so you dont know if they are Dd or
DD
Explain weak D variant Correct Answer: decreased quantities of the D antigen, so
they do NOT test as D-positive with routine immediate spin testing, instead,
positive reaction is only seen at the "AHG phase"
Differentiate among the 3 theories of the weak D variant Correct Answer: 1.
inherited- weakened expression of D
2. CD transposition- still complete D (in both of these cases the C allele is in the
trans position in relation to the D allele.)
3. Partial D- missing piece of D and can make an antibody
Given a weak D variant theory, determine if transfused weak D red blood cells into
a D negative recipient would stimulate anti-D production Correct Answer: it
depends on the cause of the weak D- transpositional effect, no, this individual will
not make an anti-D if transfused D pos blood because they have complete D
antigen. Same for inherited weak D- complete antigen. The individual who types
Answers
Compare the antibody discovered by Landsteiner and Weiner with the antibody
discovered by Levine and Stetson around 1940. Correct Answer: Levine and
Stetson- discovered Rh blood group, mother gave birth to a stillborn, mother began
to hemorrhage, father and mother same ABO group, gave mother blood from
father-> reaction
Landsteiner/Weiner- discovered D antigen when antibody was created in Rhesus
monkey when exposed to human red cells- 85% human cells were agglutinated
State the five major antigens in the Rh blood group system and their anti-thetical
alleles. Correct Answer: D antigen- no true antithetical allele (D-amorph denotes
absence of D)
C antigen- c is antithetical allele
E antigen- e is antithetical allele
Explain the "d antigen". Correct Answer: Rh is a misnomer- used to describe the red
cell D antigen
Positive is presence of D antigen ~80%
Negative is absence of D antigen ~15%
d is an amorph (no detectable antigen)- no anti-D antibody
Explain the Fisher-Race theory (DCE nomenclature) of inheritance of Rh blood
group system. Correct Answer: 3 closely linked sets of allelic genes- Dd, Cc, Ee
Move as a unit have one or the other codominant
d is lack of D
,What are the eight combinations of the antigens for Fisher-Race? Correct Answer:
Dce
DCE
DcE
DCe
dce
dCE
dcE
dCe
cde/cde antibodies Correct Answer: anti-D, anti-C, anti-E
Define phenotyping. Correct Answer: identification of antigens
cannot always determine genotype- molecular testing determine this
the following used: anti-D, anti-C, anti-c, anti-E, anti-e
Explain the Weiner theory of inheritance of the Rh blood group system. Correct
Answer: 1 gene results in production of agglutinogen which is composed of blood
factors
current loci theory: two loci; Rh genes are located on chromosome 1 and very
closely linked:
loci 1 encodes presence/absence of D
loci 2 encodes presence/absence of Ce, cE, ce, or CE
, Discuss Rosenfield's influence on the Rh nomenclature. Correct Answer: system
indicates the presence or absence of antigen on the cell; provides a straightforward
description of cell phenotype
minus sign= absence of antigen
if not typed for, it should not appear in the sequence
Justify why the D antigen is the most important antigen next to the ABO blood
group system. Correct Answer: most immunogenic- upon exposure to D antigen
through transfusion or pregnancy, 80-90% D neg will make anti-D
present on RBC before birth-prior to RhIg it was the most frequent cause of HDFN
(mom make anti-D antibody and can hurt baby if it has antigen)
Discuss the importance of antigen frequencies when searching for compatible blood
for a patient with an antibody. Correct Answer: ID of antigens cannot always
determine genotype (D doesnt have a partner-so you dont know if they are Dd or
DD
Explain weak D variant Correct Answer: decreased quantities of the D antigen, so
they do NOT test as D-positive with routine immediate spin testing, instead,
positive reaction is only seen at the "AHG phase"
Differentiate among the 3 theories of the weak D variant Correct Answer: 1.
inherited- weakened expression of D
2. CD transposition- still complete D (in both of these cases the C allele is in the
trans position in relation to the D allele.)
3. Partial D- missing piece of D and can make an antibody
Given a weak D variant theory, determine if transfused weak D red blood cells into
a D negative recipient would stimulate anti-D production Correct Answer: it
depends on the cause of the weak D- transpositional effect, no, this individual will
not make an anti-D if transfused D pos blood because they have complete D
antigen. Same for inherited weak D- complete antigen. The individual who types
