Deck 21: The Hla System

Question 1

What is the purpose of washing the cells after the initial cell-serum incubation in the Amos-modified antibody screen procedure?

A) To identify previously undefined alleles
B) To identify antibodies in the serum of the donor
C) To remove aggregated immunoglobulin in the serum
D) None of the above

Answer 1

C

Question 2

What is the most important step for increasing the number of bone marrow transplants performed?

A) Expand the donor pool to include related individuals.
B) Expand the donor pool to include unrelated individuals.
C) Expand the donor pool to include both related and unrelated individuals.
D) None of the above

Answer 2

C

Question 3

How is induction of tolerance achieved in kidney transplantation?

A) Administration of cytokines prior to transplant
B) Blood transfusions after transplant
C) Blood transfusions before transplant
D) None of the above

Answer 3

C

Question 4

Which of the following is an example of linkage disequilibrium?

A) The actual occurrence of haplotype HLA-B7 and HLA-Cw5 is 6%; the expected occurrence based on gene frequencies is 5%
B) The actual occurrence of haplotype HLA-C4 and HLA-B37 is 3%; the expected occurrence based on gene frequencies is 4%
C) The actual occurrence of haplotype HLA-A1 and HLA-B8 is 8%; the expected occurrence based on gene frequencies is 2%
D) The actual occurrence of haplotype HLA-A11 and HLA-DR4 is 8%; the expected occurrence based on gene frequencies is 7%

Question 5

HLA testing is useful in what other area of study?

A) Paternity testing
B) Disease correlation
C) Anthropology
D) All of the above

Question 6

The surface marker, or antigen, detected in histocompatibility testing of a single individual is referred to as HLA:

A) phenotype.
B) genotype.
C) haplotype.
D) karyotype.

Question 7

How is complement detected in HLA testing?

A) Agglutination
B) Hemolysis
C) Uptake of trypan blue dye
D) Uptake of mitomycin-C

Question 8

What does "HLA" stand for?

A) Human lymphodenapathy
B) Human lymphocyte antibody
C) Human leukocyte antigen
D) Human liver antigen

Question 9

What is the linkage disequilibrium in reference to the HLA antigens?

A) Occurrence of HLA genes more frequently in the same haplotype than would be expected by chance alone
B) Displacement of HLA genes on different chromosomes
C) Occurrence of HLA genes less frequently in the same haplotype than would be expected by chance alone
D) Crossover of HLA genes

Question 10

All of the following diseases have been associated with a significant HLA correlation except:

A) narcolepsy.
B) ankylosing spondylitis.
C) Fanconi's anemia.
D) Goodpasture's syndrome.

Question 11

What is meant by the term public as applied to HLA antibodies?

A) Antibodies that detect a single HLA gene product
B) Binding to an epitope unique to one HLA gene product
C) Binding to epitopes shared by more than one HLA gene product
D) All of the above

Question 12

Why is histocompatibility testing negated in both lung and heart transplants?

A) The donor must be living to perform HLA testing.
B) The cold ischemic time is too short.
C) The cold ischemic time is too long.
D) None of the above.

Question 13

How are the heavy chains of major histocompatibility complex (MHC) classes I and II molecules transported into the cell membrane?

A) Heavy chains are transported via extracellular fluid.
B) Heavy chains are inserted through the membrane via hydrophobic residues.
C) Heavy chains are inserted through the membrane via hydrophilic residues.
D) Heavy chains are adsorbed onto the membrane via semipermeable methods.

Question 14

Which of the following is a phenomenon in which an antiserum directed against one HLA determinant reacts with other HLA antigenic determinants?

A) Cross-reactivity
B) Linkage disequilibrium
C) Recombination
D) Conversion

Question 15

The MHC class I region encodes for all of the following genes except:

A) HLA-A
B) HLA-B
C) HLA-DR
D) HLA-C

Question 16

HLA-DR typing requires a___________ suspension.

A) T-lymphocyte
B) B-lymphocyte
C) granulocyte
D) platelet

Question 17

How is histocompatibility testing different from RBC testing?

A) Known serum is used to type antigens on test cells
B) Recipient serum is screened for the presence of antibodies
C) Crossmatch of donor cells and recipient serum is performed to determine compatibility
D) None of the above.

Question 18

Why are monoclonal antibodies able to detect a broad range of epitopes?

A) They are derived through alloimmunization
B) They are derived through xenoimmunization
C) They have both IgM and IgG specificity
D) None of the above

Question 19

The majority of HLA alloantibodies are ___________immunoglobulins.

A) IgM
B) IgG
C) IgE
D) IgA

Question 20

What is the definition of total ischemic time in heart transplantation?

A) The amount of time there is not blood flow through the organ
B) The time it takes to perform the transplant
C) The time it takes for PO₂ levels to normalize after transplant
D) The time it takes for CO₂ levels to normalize after transplant

Question 21

How many targets are required for HLA antibody screening?

A) 10
B) 20
C) 30
D) 40

Question 22

How are monoclonal HLA antibodies (MoAbs) produced?

A) The fusion of HLA antibody, producing B cells with plasmacytoma lines
B) The fusion of HLA antibody, producing T cells with plasmacytoma lines
C) The fusion of HLA antibody, producing B cells with neuroblastoma lines
D) The fusion of HLA antibody, producing T cells with neuroblastoma lines

Question 23

How might platelet survival be improved in a patient receiving platelets despite a near perfect HLA match between recipient and donor?

A) Wash the platelets before transfusion
B) Remove red blood cells from the donor unit
C) Remove leukocytes from the donor unit
D) Transfuse using a blood warmer

Question 24

Between which two loci are recombination (crossing over) most likely to occur?

A) HLA-A and HLA-B
B) HLA-DR and HLA-DP
C) HLA-B and HLA-C
D) HLA-A and HLA-DP

Question 25

In testing for the HLA-D antigens (DR, DP, DQ, etc.)___________ typing cells of each phenotype are set up in an MLR as against the test cells.

A) heterozygous/responders
B) homozygous/stimulators
C) heterozygous/stimulators
D) homozygous/responders

Question 26

What is the most important pre-transplant test performed on the recipient in a heart transplantation?

A) HLA-crossmatch
B) Red blood cell antibody screen
C) HLA-antibody screen
D) Red blood cell-crossmatch

Question 27

A platelet recipient whose HLA phenotype includes A3, B7; A11, B42 is transfused from a A1, B7; A3, B13 donor. Given the following CREG (Cross-Reactive Groups), what would you expect the outcome of this transfusion to be? A1-CREG: A1,36,3,9(23,24),10(25,26,34,66),11, 19(29,30,31,32,33)28 B7-CREG: B7,42,22(54,55,56),27,40(60,61)13,41,47,48

A) The donor would experience platelet refractoriness because A3 and A11 and B13 and B42 are not cross-reactive
B) The donor would benefit from this transfusion because A3 and A11 and B13 and B42 are cross-reactive
C) The recipient would experience platelet refractoriness because A3 and A11 and B13 and B42 are not cross-reactive
D) The recipient would benefit from this transfusion because A3 and A11 and B13 and B42 are cross-reactive

Question 28

When the entire set of A, B, C, DR, DQ, and DP antigens are located on one chromosome, it is called a:

A) phenotype.
B) genotype.
C) haplotype.
D) karyotype.

Question 29

Which of the following is acceptable for cytotoxicity techniques?

A) EDTA
B) ACD
C) Serum
D) CPDA-1

Question 30

Recipient lymphocytotoxic HLA-antibody to donor antigens is associated with:

A) accelerated graft rejection.
B) platelet refractoriness.
C) respiratory distress.
D) both A and B.

Question 31

What does the "R" signify in the HLA-DR locus?

A) Recessive gene
B) Red cell predominance
C) RNA
D) Subregion of D

Question 32

What kidney transplant strategy is satisfied through matching of the donor and recipient antigens?

A) Use of immunosuppressive agents
B) Reduction of graft "foreignness"
C) Induction of tolerance
D) None of the above

Question 33

The genetic region that contains surface antigens or receptors responsible for the recognition and elimination of foreign tissues is referred to as:

A) D-related locus.
B) major histocompatibility complex.
C) deoxyribonucleic acid.
D) complement-dependent microlymphocytotoxicity

Question 34

Why are T cells unacceptable for cytotoxicity testing using fluorescent labeling?

A) T cells are not involved in cytotoxicity testing
B) T cells do not adhere to nylon wool
C) T cells lack immunoglobulin on their surface
D) The suppressor activity of T cells renders the membrane protein inaccessible to the label antibody

Question 35

MHC class II molecules are expressed on all of the following except:

A) monocytes.
B) endothelial cells.
C) B lymphocytes.
D) platelets.

Question 36

Kidney transplants are used to treat which disease?

A) Di Guglielmo's syndrome
B) End-stage renal disease
C) Graves' disease
D) Erythropoietin deficiency

Question 37

A common technique used for HLA class II typing that involves amplification of specific DNA sequences for hybridization is called:

A) complement-dependent cytotoxicity (CDC).
B) mixed lymphocyte reaction (MLR).
C) polymerase chain reaction (PCR).
D) lymphocytotoxicity.

Question 38

In HLA testing, what is the purpose of mineral oil contained in the testing well?

A) To prevent evaporation of antisera during incubation
B) To create a viscous microenvironment
C) To act as an antigen-antibody complex potentiator
D) To provide height to the testing well

Question 39

What is the main purpose of crossmatching before transplantation?

A) To identify antibody in the potential donor to antigen present on recipient cells
B) To identify antibody in the serum of the potential recipient to antigens present on donor tissues
C) To identify antigen in the recipient cells to antibody present in donor serum
D) To identify antigen present on donor tissues to antibody present in recipient serum

Question 40

Which MHC region encodes for complement proteins?

A) Class I
B) Class II
C) Class III
D) None of the above

Question 41

Patients who have been presensitized to HLA antigens have a much higher graft survival rate in liver transplantation than nonsensitized patients.

Question 42

The HLA-A locus antigens A2, A23, A24, and A28 make up the:

A) A4-CREG
B) A3-CREG
C) A2-CREG
D) A8-CREG

Question 43

The primary indication for pancreas transplantation is:

A) Fabry's disease.
B) Karposi's sarcoma.
C) diabetes.
D) Crohn's disease.

Question 44

A double-lung transplant is indicated in which of the following disorders?

A) Pneumonia
B) Pulmonary fibrosis
C) Primary hypertension
D) Cystic fibrosis

Question 45

A patient who has been presensitized to foreign HLA antigens will demonstrate___________ if the donor tissue expresses the same antigens.

A) graft survival
B) graft rejection
C) chimerism
D) ABO conversion

Question 46

The majority of cross-reactive alloantibodies detect HLA specificities of allelic molecules coded by the same locus.