Unit 2 Questions Flashcards
An individual from Bombay who has inherited the Le gene will have a phenotype of:
Le(a+b-)
Individuals who are Le(a-b-) and can develop lewi antibodies without exposure to Lewis antigens are called:
Naturally occurring
Which of the following may be a possible cause for the lack of expression of Lewis antigens during pregnancy?
Increased ratio of plasma lipoproteins to RBC mass
A patient was phenotypes for the presence of Lewis antigens (Lea and Leb). A 3+ reaction was observed when patient cells were incubated with anti-Lea. No reaction was observed with anti-Leb. Based on these results, the patients phenotype is_________ and the patient is a ________ of ABH substances
- Le(a+b-)/nonsecretor
What percentage of the white population inherits the Le gene?
90%
Approximately what percentage of the black population is [Le(a-b-)]?
22%
In order for an individual to express Leb antigen on their RBCs, the must have inherited which gene?
- All of the above
- Le
- Se
- H
Pregnant women usually express which phenotype?
Le(a-b-)
Why is anti-LebL the antibody of choice when phenotyping RBCs?
It recognizes any Leb antigen independent of ABO types
Persons who inherit the Se and Le genes will have ______ A or B glycolipids in plasma than persons who are Se Le
Fewer
All of the following statements are representative of Lewis antibodies except:
They are destroyed by enzymes
Anti-Lea, which is reactive a the Coombs phase, may cause what kind of hemolysis?
In vivo
RBCs that phenotypes as [Le(a-b-)] are inherited with plasma containing Lea substance. The RBCs convert to the phenotype [Le(a+b-)]. Whereas the same RBCs incubated with saliva containing Lea substance do not convert. Why?
Glycoprotein are not absorbed onto RBC membranes
What does the type 1 chain refer to?
- beta-linkage of the number 1 carbon of galactose to the number. 3 carbon of N-acetylglucosamine residue of precursor structure
Lewis cell-bound antigens absorbed from plasma onto the RBC membranes are:
Glycolipids
Lewis antibodies are of what immunoglobulin class?
IgM
What enzyme is responsible for Lewis Specificity?
L-fucosyltransferase
Where are Lewis antigens found?
*all of the above
- plasma
- saliva
- milk
What substances would be present in the saliva of a person with the LeLe HH SeSe AA genotype?
A
H
Lea
Leb
How is Leb susbstance formed?
L-fructose is added to subterminal N-acetylglucosamine of type 1 H substance
Which of the following statments is false?
- Lewis antibodies do not bind complement
What would be the probable genotype of a patient who phenotypes as ABLe(a-b-)?
- lele sese HH AB
What is found in secretions of Le(a-b-) individuals?
None of the above
At which phase are Lewis antibodies usually detected?
Immediate spin
How does anti-Lea differ from anti- Leb?
Anti-Lea can bind complement more efficiently
Why are Lewis antibodies not generally implicated in HDN?
Lewis antibodies are IgM and cannot cross the placenta
Which blood group system is not based on carbohydrates?
Rh
How is Le(y) formed?
- Fucose A(1-3) G1cNac is added to type 2H precursor substance
It was discovered that a patient who was to receive two units of packs RBCs had an anti-Lea circulating in his system. What would be the proper procedure?
- the two units do not necessarily need to be Lea-negative but should be crossmatched through atleast 37 degrees and crossmatch compatible before given
The true Lewis phenotype will normally be detected at what age?
- not necessarily ever, as circumstances such as pregnancy may alter or mask an individual’s true Lewis phenotype
Which of the following statements about the Lewis system in not true?
Secretion of Lewis substance is controlled by the Se gene
P1 antigens:
Take up to 6-7 years to develop
I and i antigens are found in plasma, serum, and what other possible source?
*all of the above
- Breast milk
- urine
- saliva
Persons with the Kidd-null phenotype have been found in:
New Zealand
Lutheran antibodies are rarely associated with causing HDN for which of the following reasons?
*all of the above
- Lutheran antigens are poorly developed at birth
- Maternal Lutheran antibodies are absorbed onto glycoprotein on the placenta, decreasing the likelihood of HDN
- Luther antibodies are generally IgM class and normally do not cross the placenta
Which of the following is not involved in the Kell blood group system?
- Jka
Where are Duffy antigens found?
RBCs
What is the most common Kidd phenotype in the black population?
- Jk(a+b-)
Why is dosage inconsistent in the Duffy blood group?
- the genotype could be inherited as FyaFya or FyaFy for for Fy(a+b-) RBCs
Why is it relatively easy to find compatible unit for a patient with anti-K?
Kell is a low-frequency antigen
RBCs were treated with FI in to help rule in anti-M from a panel study. Cells not treated reacted at 2+at immediate spin and 1+ at 37C. There was no reactivity in the Coombs phase. FI in-treated cells demonstrated a ______ reaction with patient serum containing anti-M
Negative
The Fy5 antigen has not been shown to be the result of an interaction between Duffy genes and:
Rh
A blood bank technologist needed to confirm the presence of anti-P1 in a patient specimen. Fresh cells were not available for use, so an old panel that contained cells positive for P1 was used. No cells positive for the antigen reacted at any phase of the antiglobulin test, whereas cells from the screening cells showed specificity for the presence of anti-P1. What is a possible explanation for this?
- P1 antigen deteriorates rapidly upon storage
What will happen to I antigen expression when ABH sugars are removed from the RBCs?
Increased expression
What is the International society of Blood Transfusion (ISBT) assignment for the antigen P2?
003001
What is the definition of a blood group system?
A group of antigens produced by alleles at a single gene locus
Where are the Kell blood group antigens found?
RBCs
Anti-M was detected in a 27-year old man before surgery. Unit negative for M antigen were not available; however, the units were approved for transfusion when major crossmatch using M+N+ donor cells and patient serum resulted in:
IS - 1+, 37= 0, AHG = 0
Which of the following is known to enhance K antigen expression in the antihuman globulin test?
Polyethylene glycol
Anti-Lea reacts at what temperatures?
Room temperature
At what phase of the antihuman globulin test will anti-Kell be detected?
AHG
What is the function of a GPB-GPA hybrid (anti-Lepore type)?
Encodes normal GPA
Persons who phenotype negative for U antigen lack Ss-SGP because of a partial or complete deletion of ________
GPB
What sample requirement is essential for ID of a Kidd antibody?
Fresh serum or plasma
What does the U in U antigen stand for?
Universal
Infection with which organism is associated with naturally occurring IgM anti-K
*All of the above
- escheriachia coli
- campylobacter coli
- mycobacterium species
The M and N antigens are found in which glycoprotein?
Glycophorin A
How can pathological anti-I be differentiated from benign anti-I?
- broad thermal range of reactivity
Which of the following distinguishes the recessive LuLu gene from the dominant In(Lu) gene?
Normal expression P1
All of the following are characteristics of of Kidd antibodies except:
Naturally occurring
When RBCs are placed in a solution of 2M urea, the RBCs will lyse. However, it has been shown for that which RBCs are resistant to lysis?
Jk(a-b-)
What MN phenotype is found in highest frequency in the white population?
M+N+
The M and N antigens exhibit dosage. Therefore, if a person inherits the Homozygous genotype MM, their RBCs will react________ with anti-M than/as those of a person with a heterozygous genotype of MN
Stronger
Anti-M will react strongest with which cells?
M+N-
The Lu gene shares chromosomes 19 with what other blood group gene?
- All of the above
- H
-Le
-LW
The homozygous phenotype Fy(a+b-) has ________ antigenic Fy sites than heterozygous cells, Fy(a+b+)
More
What is the source of anti-M lectin?
Iberia Amara
All of the following are grouped with the para-Kell antigen except:
K11
What anemia will result in an increased expression of i antigen, which exceeds that found on control cord cells?
CDA type II
The Kell gene is located on the long arm of which chromosome?
7
At what are does I antigen become detectable on infant cells?
18 month
What RBC antigens do McLeod individuals express?
TracekKpbJsbK11
What characteristics differentiates Ss antigens from MN antigens?
Enzyme degradation
A person who inherits alleles Fya and Fyb will carry which antigens on their RBCs ?
Both Fya and Fyba antigen
What is the ISBT designation for the li blood groups?
207
On which malaria receptor site is Duffy antigen dependent?
Junction receptor
The structures that carry the P antigen also carry which determinants?
- All of the above
- A
- B
- I
A patient who has a pathologic autoanti-I must be transfused with:
A blood warmer
What is the etiology of dialysis- associated anti-N?
- Formaldehyde alters the N antigen so that it is recognized as foreign
The genes that code for GPA and GPB are closely linked on the long arm of which chromosome?
4
Persons who express the phenotype P2 are at risk for developing anti-P1 when handling what animal species?
Pigeons
Persons who inherit the In(Lu) gene will exhibit:
Jk(a-b-) RBCs that can absorb anti-Jka
Persons who are negative for Duffy antigen are less likely to contract which of the following disease?
Malaria
What abnormal blood cell morphology is associated with McLeod Phenotype?
Acanthocytes
What organism is capable of converting Jk(b-) RBCs to Jk(b+)?
Micrococcus species
What is the ISBT designation for the Lutheran blood group system?
LU
How are lipids dissociated from the RBC membrane for biochemical studies?
Organic solvents
What type of hemolytic transfusion reaction (HTR) occur more frequently in patients with Jk antibodies?
Delayed
Anti-I is found in association with what microorganism?
Mycoplasma pneumoniae
Autoantibodies to Jka have been found in patients taking:
Methyldopa
What adult phenotype is rich in i antigen and common to the white population?
- i1
Units that were positive for P2 antigen gad to be crossmatched with serum of a patient containing the corresponding antibody because of a short supply of blood. Which of the following crossmatch results would be considered acceptable for transfusion?
IS = 1+, 37 = 0, AHG = 0
Most blood group alleles are:
Codominant
What Kidd antibody will react with all panel cells and phenotype are Jk(a-b-)?
Anti-Jk3
What is the most common genetic combination in the Kell blood group system?
- kKpbJsbK11
All of the following are characteristics of Duffy antibodies except:
- they are not implicated in HDN
Anti-Jka was identified in a previously transfused patient. Five cells that were homozygous for Jka yielded 2+ reactions in the AHG phase. The same cells were treated with ficin and yielded 3+ reactions in AHG. Therefore, Jka is _________ by enzyme treatment
Enhanced
All of the following are characteristics of the Ena antigen except:
It is a low-frequency antigen
What sequence of antigens coincides with strongest immunogen to weakest immunogen?
D, K, Fya, Fyb
Anti-N will react stronger with which phenotype?
M-N+
The Ii antigens are found on the membranes of which structures?
- All of the above
- platelets
- RBCs
- Leukocytes
Where are the Kidd antigens found?
RBCs
Why do En(a-) individuals have a reduced chance of infection with plasmodium falciparum?
- there is a reduction in N-acetylneuraminic acid
How is the Ena antigen related to the Wr(a-b-) phenotype?
En(a-) RBCs are all Wr(a-b-)
Anti-N is know to occur in _______ patients undergoing dialysis with equipment sterilized by formaldehyde?
Renal
Anti-Anton recognizes the same specificity as:
Anti-Wj
Approximately what percentage of the black population are s-?
3%
What can be done to rule in anti-M when only M+N+ RBCs are available?
Decrease the serum-to- cell ratio
What fatal disease is associated with the McLeod phenotype?
Chronic granulomatous disease
Which of the following statements regarding individuals who are Fy(a-b-) is true?
The presence of Fya in the tissue of individuals who are black who are Fy(a-b-) prevents those individuals from forming Anti-Fyb
Why is it strongly recommended that only homozygous cells be used when ruling out Kidd antibodies?
Anti-Jka may appear compatible with heterozygous cells [Jk(a+b+)]
A woman undergoing a hysterectomy requires two units of blood. The antibody screen was negative. One unit was incompatible in the Coombs phase (2+), the other unit was compatible. Give a reason why this antibody was not detected in the antibody screen
Existence of a low-frequency antigens
What is the etiology of chronic granulomatous disease (CGD)?
Phagocytes are unable to generate hydrogen peroxide, which is used to kill invading bacteria
What are the antibody characteristics of Fy3, Fy4, and Fy5?
- All of the above
- Reactive at AHG
- Immunogenic
- IgG
What finding may protect individuals from making alloanti-Lub in dominant In(Lu) genotypes?
The ability to absorb and elute anti-Lub
Persons who are genetically P1 may serologically type as P2 because of:
Inheritance of the In(Lu) gene
What biochemical observations signify a protein composition to the Kell antigens?
Inactivation at 56 C
Most Kell autoantibodies are directed against which antigens that are usually undefined?
High-frequency
Black persons who genotype as Fy4Fy4 will phenotype as:
Fy(a-b-)
What is the ISBT designation for the Kell system?
006
The Duffy antigens have mobility characteristics similar to what other antigenic structure?
MN-SGP
What Kell phenotype is found in highest frequency in the white population?
K-k+
All of the following are characteristics of anti-M except:
The reacts tronger with enzyme-treated cells
Anti-i is found in association with what disease?
IM
What is the ISBT designation for the Kidd blood group system?
009
What biochemical substitute is responsible for the i determinant?
Two repeating N-acetyllactosamine units on H2 structures
What serologic factor distinguishes anti-Fy3 from anti-Fya or anti-Fyb?
It is not destroyed by enzymes
What portion of GPA reacts with anti-EnaFR?
Ficin resistant
Persons who phenotype as Fy(a-b-) are resistant to infection by which organism?
Plasmodium vivax
Alloanti-Lub will react ______ with Lu(a+b+) cells than/as with Lu(a-b+) cells
Weaker
