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Flashcards in Exam 3 Deck (60):
1

A primary immune response against influenza virus produces antibodies that bind to _____.

a. protein toxins
b. variable surface glycoproteins
c. EBNA-1
d. hemagglutinin and neuraminidase
e. gp41 and gp120

d. hemagglutinin and neuraminidase

2

The serotypes of Streptococcus pneumoniae differ in their _____.

a. capsular polysaccharides
b. variable surface glycoproteins
c. superantigen products
d. ability to fix complement
e. rates of gene conversion

a. capsular polysaccharides

3

Shingles is associated with infection by _____.

a. Epstein–Barr virus
b. Staphylococcus aureus
c. Candida albicans
d. Listeria monocytogenes
e. herpes zoster

e. herpes zoster

4

All of the following are associated with superantigens except _____.

a. activate α:β T cells
b. effective at minuscule concentrations
c. processing to peptides is not required for T-cell activation
d. massive production of IL-2, IFN-γ, and TNF-α
e. nonspecific activation of 2–20% of body’s CD8 T cells

e. nonspecific activation of 2–20% of body’s CD8 T cells

5

Which of these characteristics is not true of IFN-γ?

a. When it acts on target cells, it enhances the engulfment and killing of bacteria.
b. It is the major activating cytokine of macrophages.
c. It activates the JAK–STAT signal transduction pathway after binding to its cognate receptor.
d. It is secreted by CD8 cytotoxic T cells, CD4 TH1 cells, and NK cells.
e. It is secreted and functions as a monomer but facilitates the dimerization of its receptor.
f. It is able to render target cells responsive even if they express only one functional allele of IFNγR1.

e. It is secreted and functions as a monomer but facilitates the dimerization of its receptor.

6

Paroxysmal nocturnal hemoglobinuria is caused by _____.

a. a profound deficiency of neutrophils
b. complement-mediated lysis of erythrocytes
c. leukocytosis
d. immune-complex deposition in tissues
e. defects in recruitment of phagocytes to infected tissues

b. complement-mediated lysis of erythrocytes

7

Severe combined immune deficiency (SCID) describes a condition in which neither _____ nor _____ are functional.

a. innate; acquired immune responses
b. classical; alternative pathways of complement
c. T-cell-dependent antibody responses; cell-mediated immune responses
d. MHC class I; MHC class II molecules.

c. T-cell-dependent antibody responses; cell-mediated immune responses

8

Which of the following explains why Streptococcus pneumoniae can infect an individual recurrently?

a. S. pneumoniae is never completely eradicated during an infection and can reactivate if the host is immunocompromised.
b. Previous infection with S. pneumoniae wears down the immune system over time.
c. Anti-capsular antibodies are cleared from the host quickly after an active infection.
d. The capsular polysaccharide antigens of S. pneumoniae do not induce immunological memory.
e. Immune responses against S. pneumoniae are serotype-specific and protect only against strains that
possess the same capsular polysaccharide antigens.

e. Immune responses against S. pneumoniae are serotype-specific and protect only against strains that
possess the same capsular polysaccharide antigens.

9

All of the following contribute to new epidemics and the long-term survival of the influenza virus in the human population, except:

a. The virus loses the capacity to express hemagglutinin, thereby rendering neutralizing antibodies useless.
b. The RNA genome of the influenza virus is subject to point mutations during viral replication.
c. New viral strains possess epitopes not recognized by antibodies made in the previous epidemic.
d. The first influenza strain provoking a primary immune response constrains the types of antibodies
made during a subsequent encounter with a different strain.
e. None of the above.

a. The virus loses the capacity to express hemagglutinin, thereby rendering neutralizing antibodies useless.

10

An epidemic affects _____, whereas a pandemic affects _____.

a. susceptible individuals; immune individuals
b. local populations; global populations.
c. immune individuals; susceptible individuals
d. global populations; local populations
e. local populations; immune individuals

b. local populations; global populations.

11

Trypanosomes escape from adaptive immunity by altering the type of _____ expressed on the parasite surface.

a. variable surface glycoprotein (VSG)
b. neuraminidase
c. capsular polysaccharide
d. hemagglutinin
e. superantigen

a. variable surface glycoprotein (VSG)

12

Which of the following is not a characteristic of staphylococcal enterotoxins?

a. They cause T cells to divide and differentiate into effector T cells.
b. They stimulate between 2% and 20% of the total T-cell population.
c. They cause excessive synthesis and release of cytokines.
d. They bind to MHC class I molecules and T-cell receptors.
e. They induce suppression of the immune response by causing T cells to undergo apoptosis.

d. They bind to MHC class I molecules and T-cell receptors.

13

Which of the following statements regarding inherited immunodeficiency diseases is correct?

a. Affected individuals are less susceptible to infection.
b. Mortality rates are reduced by the administration of antibiotics to affected individuals.
c. Most deficiency syndromes are caused by dominant gene defects.
d. Women are more likely than men to inherit X-linked immunodeficiencies.
e. Extracellular bacterial infections are common in deficiency syndromes with T-cell defects.

b. Mortality rates are reduced by the administration of antibiotics to affected individuals.

14

Which statement regarding retrovirus proviruses is false?

a. Proviruses are flanked by repetitive sequences called long terminal repeats (LTRs).
b. Proviruses consist of double-stranded DNA.
c. The host cell must provide the transcriptional and translational machinery in order for RNA and
protein products to be made from proviruses.
d. A cDNA intermediate is required in order to produce a provirus.
e. Proviruses form immediately after the RNA genome assembles with viral proteins and infectious
virions are produced.

e. Proviruses form immediately after the RNA genome assembles with viral proteins and infectious
virions are produced.

15

Reverse transcriptase is a _____ encoded by _____.

a. DNA-dependent DNA polymerase; influenza virus
b. DNA-dependent DNA polymerase; HIV
c. RNA-dependent DNA polymerase; influenza virus
d. RNA-dependent DNA polymerase; HIV
e. RNA-dependent RNA polymerase; HIV

d. RNA-dependent DNA polymerase; HIV

16

Which of the following is not mediated by antibodies?

a. type III hypersensitivity
b. type I hypersensitivity
c. type IV hypersensitivity
d. type II hypersensitivity
e. None of the above.

c. type IV hypersensitivity

17

_____ hypersensitivity reactions interact with soluble epitopes and not cell-surface associated epitopes.

a. type I and II
b. type I and IV
c. type II and III
d. type II and IV
e. type I and III

e. type I and III

18

During a primary immune response IgM sometimes switches to IgE. Which of the following best describes the consequence of this early switch?

a. The IgE produced would have low affinity for antigen.
b. The B cell would switch again to IgG3.
c. The B cell would remain in the germinal center but would not differentiate into a plasma cell.
d. The B cell would die by apoptosis.
e. The IgG produced would have low affinity for antigen.

a. The IgE produced would have low affinity for antigen.

19

Which of the following regarding FcεRI is false?

a. It is expressed on the surface of mast cells and basophils.
b. It is a low-affinity receptor involved in type I hypersensitivity reactions.
c. It binds to IgE in the absence of antigen.
d. It is a membrane-bound tetramer.
e. It contains signaling components that re activated following antigen cross-linking.

b. It is a low-affinity receptor involved in type I hypersensitivity reactions.

20

Identify the mismatched pair.

a. TNF-α: immediate release from mast cells
b. connective tissue mast cells: chymotryptase
c. lipid mediator: prostaglandins
d. mucosal mast cell production: T-cell immunodeficiencies
e. leukotrienes: increase vascular permeability.

d. mucosal mast cell production: T-cell immunodeficiencies

21

Which of the following directly inhibits the cyclooxygenase pathway by inhibiting the activity of prostaglandin synthase?

a. aspirin (acetyl salicylate)
b. ADAM10
c. experimental anti-IgE
d. chymotryptase
e. ADAM33.

a. aspirin (acetyl salicylate)

22

Aspirin (acetyl salicylate) inhibits prostaglandin synthesis by binding irreversibly to prostaglandin synthase, the first enzyme in the _____ pathway.

a. carboxypeptidase
b. metalloprotease
c. lipooxygenase
d. cyclooxygenase
e. peroxidase

d. cyclooxygenase

23

During the course of a successful desensitization process, the patient’s antibodies will change from an _____isotype to an _____ isotype.

a. IgG1:IgG4
b. IgG4:IgE
c. IgE:IgG4
d. IgE:IgM
e. IgA:IgM

c. IgE:IgG4

24

Anita Garcia, 17 years old, and her roommate Rosa Rosario were celebrating a friend’s birthday at a dessert buffet at a local restaurant when Anita developed acute dyspnea, and angioedema. She complained of an itchy rash, and then had difficulty swallowing. Rosa drove Anita to the emergency room two blocks away rather than wait for an ambulance. As they approached the hospital, Anita lost consciousness. This medical emergency would most probably result in immediate _____ before any subsequent treatment.

a. intravenous injection of corticosteroids
b. intravenous injection of antihistamine
c. intravenous injection of antibiotics
d. subcutaneous injection of epinephrine
e. intravenous injection of a nonsteroidal anti-inflammatory drug.

d. subcutaneous injection of epinephrine

25

The underlying molecular basis for distinguishing blood-group antigens A, B and O is _____ at the erythrocyte surface.

a. structural polymorphisms in the Rhesus D antigen
b. the presence or absence of fucose in glycolipids
c. the levels of MHC class I and class II molecules.
d. differences in the peptide attached to the lipid ceramide
e. differences in the oligosaccharide attached to the lipid ceramide

e. differences in the oligosaccharide attached to the lipid ceramide

26

Which of the following is a permissible match between a blood donor and a recipient (donor: recipient)?

a. O +: AB –
b. AB +: O –
c. A +: A –
d. O –: AB +
e. AB –: O +

d. O –: AB +

27

The direct pathway of allorecognition involves interaction of _____, whereas the indirect pathway of alloreaction involves interaction of _____.

a. recipient T cells with allogeneic HLA molecules on donor dendritic cells; recipient T cells with peptides of allogeneic HLA molecules on recipient dendritic cells
b. donor T cells with allogeneic HLA molecule on recipient dendritic cells; recipient T cells with allogeneic HLA molecules on donor dendritic cells
c. recipient T cells with allogeneic HLA molecules on donor dendritic cells; donor T cells with allogeneic HLA molecule on recipient dendritic cells
d. recipient T cells with peptides of allogeneic HLA molecules on recipient dendritic cells; donor T cells with peptides of allogeneic HLA molecules on donor dendritic cells.

a. recipient T cells with allogeneic HLA molecules on donor dendritic cells; recipient T cells with peptides of allogeneic HLA molecules on recipient dendritic cells

28

The risk of _____ is the primary complication in bone marrow transplants.

a. acute host-versus-graft disease
b. acute graft-versus-host disease
c. hyperacute rejection
d. chronic rejection
e. cancer

b. acute graft-versus-host disease

29

_____ from a bone marrow transplant facilitate alloreactive responses, causing the condition defined as acute graft-versus-host disease.

a. Natural killer cells
b. Dendritic cells
c. Thymocytes
d. Mature B cells
e. Mature T cells

e. Mature T cells

30

Males engrafted with HLA-identical bone marrow from their sisters develop graft-versus- host disease because _____.

a. NK-cell alloreactions occur
b. T cells develop in the male thymus that are not tolerant to minor histocompatibility
antigens expressed by the sister
c. there are differences between the sexes in how self proteins are modified post-
translationally
d. mature T cells in the graft have specificity for male-specific minor histocompatibility antigens
e. residual female hormones in the graft cause upregulation of HLA class I on male dendritic cells presenting minor histocompatibility antigens.

d. mature T cells in the graft have specificity for male-specific minor histocompatibility antigens

31

George Cunningham was diagnosed with Crohn’s disease when 23 years old. He was experiencing acute abdominal pain, diarrhea, rectal bleeding, anemia and weight loss. He did not respond to conventional immunosuppressive therapies and was given a course of infliximab, an anti-TNF-α monoclonal antibody that suppresses inflammation by blocking TNF-α activity. On day 12 after receiving his first infusion, he developed a mild fever, generalized vasculitis, swollen lymph glands, swollen joints and joint pain. Traces of blood and protein were detected in his urine. Which of the following is the most likely cause of these recent symptoms?

a. Type III hypersensitivity caused by immune complex deposition in blood vessels.
b. Type II hypersensitivity leading to thrombocytopenia.
c. Type I hypersensitivity involving anaphylaxis.
d. Type II hypersensitivity leading to hemolytic anemia.
e. Type IV hypersensitivity involving CD8 T-cell cytotoxicity.

a. Type III hypersensitivity caused by immune complex deposition in blood vessels.

32

The term _____ is used to describe polymorphic antigens that vary between individuals of the same species.

a. xenoantigens
b. immunoantigens
c. histoantigens
d. autoantigens
e. alloantigens

e. alloantigens

33

Which of the following best explains why a bone marrow donor needs to be HLA-matched to the recipient?

a. Reconstituted T cells are restricted by donor, not recipient, HLA allotypes.
b. The bone marrow transplant contains enough mature T cells to reconstitute the recipient
and the recipient provides the antigen-presenting cells.
c. Without an HLA match, the donor-derived thymocytes undergo negative selection.
d. The recipient’s MHC molecules mediate positive selection of thymocytes in the thymus
that interact with donor-derived MHC molecules in the periphery.
e. If the donor is not HLA matched, the reconstituted T cells will be autoreactive.

d. The recipient’s MHC molecules mediate positive selection of thymocytes in the thymus
that interact with donor-derived MHC molecules in the periphery.

34

Richard French, 53 years old, was diagnosed with chronic myelogenous leukemia. His elder brother Don is HLA-haploidentical and will donate bone marrow. Richard’s oncologist has recommended him to a medical center that favors using bone marrow depleted of mature T cells prior to infusion. The most likely rationale for employing the practice of T-cell depletion is that _____.

a. because Don is HLA-haploidentical and male, there is no risk of alloreactivity toward major or minor histocompatibility antigens
b. mature T-cell chimerism is required to establish long-term tolerance
c. T-cell depletion will remove alloreactive T cells from the donor and prevent the potential for graft-versus-host disease (GVHD)
d. because of Don’s age, the expected bone marrow harvest is already marginal for successful engraftment, and depletion measures would compromise the yield of stem cells
e. the benefit of using a cocktail of immunosuppressive drugs outweighs the risk of contaminating the bone marrow during T-cell depletion.

c. T-cell depletion will remove alloreactive T cells from the donor and prevent the potential for graft-versus-host disease (GVHD)

35

Forty-four-year old Danielle Bouvier is on the waiting list for a kidney transplant and is receiving weekly dialysis. Her HLA type is: HLA-A: 0101/0301; HLA-B: 0702/0801; HLA-DRB1: 0301/0701. Today, Danielle’s physician informed her that several potential kidney donors are available. Which of the following would be the most suitable?

a. A: 0301/0201; B: 4402/0801; DRB1: 0301/0403
b. A: 0101/0101; B: 5701/0801; DRB1: 0701/0701
c. A: 0101/0301; B: 0702/5701; DRBA: 0403/0301
d. A: 0301/2902; B: 1801/0801; DRB1: 0301/0701
e. A: 2902/0201; B: 0702/0801; DRB1: 0301/13011

b. A: 0101/0101; B: 5701/0801; DRB1: 0701/0701

36

What type of hypersensitivity reaction would result from a mismatched blood transfusion?

a. Type IV
b. Type III
c. Type I
d. Type II

d. Type II

37

If _____ occurs in an organ to be transplanted, endothelial activation, leukocyte infiltration, inflammatory cytokine production, and complement activation may occur.

a. ischemia
b. a mixed lymphocyte reaction
c. the transfusion effect
d. kidney dialysis
e. myeloablative therapy

a. ischemia

38

Acute rejection of a kidney graft involves the activation of recipient T cells by _____ of _____ origin.

a. B cells; recipient
b. dendritic cells; recipient
c. macrophages; recipient
d. B cells; donor
e. dendritic cells; donor

e. dendritic cells; donor

39

When donor MHC:donor self-peptide complexes activate recipient T cells, _____.

a. suppression occurs and transplanted organs are tolerated
b. hyperacute rejection of transplanted organs occurs
c. complement pathways are activated
d. acute rejection of transplanted organs occurs
e. an indirect pathway of allorecognition occurs

d. acute rejection of transplanted organs occurs

40

The extent to which an individual’s T cells respond to allogeneic HLA expressed on irradiated donor cells can be measured in vitro using _____.

a. the mixed lymphocyte reaction
b. the panel reactive antibody test
c. a cross-match test
d. a superantigen recognition test
e. the transfusion effect assay

a. the mixed lymphocyte reaction

41

In chronic rejection, effector T cells respond to _____ complexes on _____-derived dendritic cells.

a. donor MHC class I:donor self peptide; donor
b. recipient MHC class II:donor MHC peptide; recipient
c. recipient MHC class II:donor MHC peptide; donor
d. donor MHC class II:donor self peptide; donor
e. recipient MHC class I:donor MHC peptide; recipient

b. recipient MHC class II:donor MHC peptide; recipient

42

Alloantibody production after organ transplantation involves _____.

a. the transfusion effect
b. a mixed lymphocyte reaction
c. activation of regulatory CD4 T cells
d. the indirect pathway of allorecognition by CD4 T cells
e. a switch from a chronic to an acute state of organ rejection

d. the indirect pathway of allorecognition by CD4 T cells

43

Patients who have previously received a blood transfusion that has HLA-DR allotypes in common with their kidney transplant are _____.

a. more likely to reject the graft owing to the presence of HLA alloantibodies
b. less likely to reject the graft owing to negative selection of alloreactive T-cell clones
c. less likely to reject the graft owing to the presence of regulatory CD4 T cells
d. at risk of developing a hyperacute rejection
e. at risk of developing graft-versus-host disease

c. less likely to reject the graft owing to the presence of regulatory CD4 T cells

44

_____ is a nitrogen mustard compound converted to a DNA-alkylating agent in the body that is used to inhibit cell proliferation after transplantation.

a. Methotrexate
b. Cyclophosphamide
c. Mycophenolate mofetil
d. Rapamycin
e. FK506

b. Cyclophosphamide

45

Corticosteroids interfere with chemotaxis of leukocytes by _____.

a. inhibiting the expression of adhesion molecules on endothelial vessels
b. decreasing the production of GM-CSF and IL-1
c. inducing apoptosis
d. suppressing the activity of phospholipase A2
e. reducing nitrogen oxide synthase (NOS) activity

a. inhibiting the expression of adhesion molecules on endothelial vessels

46

Which type of autoimmune disease is correctly matched with its cause?

a. type III: immune complex deposition in tissues
b. type V: cell-surface components
c. type IV: extracellular matrix-associated autoantigens
d. type I: IgE-mediated
e. type II: effector T cells

a. type III: immune complex deposition in tissues

47

Which of the following is an example of a type IV autoimmune response?

a. pemphigus vulgaris
b. autoimmune thrombocytopenia purpura
c. subacute bacterial endocarditis
d. type 1 diabetes
e. systemic lupus erythematosus

d. type 1 diabetes

48

_____ is a highly variable type III autoimmune disease in which immune complexes form and may cause glomerulonephritis of the kidney, arthritis of the joints, and vasculitis of the face.

a. Rheumatoid arthritis
b. Pemphigus vulgaris
c. Multiple sclerosis
d. Systemic lupus erythematosus
e. Goodpasture’s syndrome

d. Systemic lupus erythematosus

49

Which of the following describes myasthenia gravis?

a. Ectopic lymphoid tissue forms and impairs endocrine function.
b. The neuromuscular junction is compromised.
c. Chronic inflammation of the gut mucosa.
d. Disruption of adhesion molecules of cellular junctions.
e. Autoimmune response to proteins of anterior chamber of the eye.

b. The neuromuscular junction is compromised.

50

The reason why babies born to mothers with Graves’ disease suffer passively from the disease for only a short while after birth is that _____.

a. the newborn’s regulatory T cells suppress autoantibody production
b. very little IgM is transported across the placenta
c. the newborn’s thyroid gland develops resistance to the effects of maternal autoantibodies
d. thyroglobulin synthesis does not commence until months after birth
e. only antibodies, and not the B cells making the autoantibodies, cross the placenta

e. only antibodies, and not the B cells making the autoantibodies, cross the placenta

51

A(n) _____ binds to the antigen-binding site of another antibody.

a. cryptic epitope
b. molecular mimic
c. receptor antagonist
d. anti-idiotypic antibody
e. autoantibody

d. anti-idiotypic antibody

52

Thyroid-stimulating hormone is made in the _____ and induces the release of thyroid hormones after proteolytic processing of _____.

a. hypothalamus; thyroxine
b. pancreas; thyroglobulin
c. pituitary gland; thyroglobulin
d. pituitary gland; thyroid-stimulating hormone receptor
e. thyroid gland; thyroid peroxidase

c. pituitary gland; thyroglobulin

53

Graves’ disease causes _____, whereas Hashimoto’s disease causes _____.

a. hypoglycemia; hyperglycemia
b. hypothyroidism; hyperthyroidism
c. hyperglycemia; hypoglycemia
d. hyperthyroidism; hypothyroidism
e. glomerulonephtitis; systemic vasculitis

d. hyperthyroidism; hypothyroidism

54

Which of the following are correctly matched?

a. beta cells of pancreas: insulin production
b. alpha cells of pancreas: insulin production
c. exocrine tissue: islets of Langerhans
d. type 2 diabetes: insulin-dependent diabetes mellitus
e. alpha cells of pancreas: somatostatin production

a. beta cells of pancreas: insulin production

55

_____ is the term used to describe how pathogen antigens resemble host antigens and can sometimes trigger autoimmune disease.

a. intramolecular epitope spreading
b. molecular mimicry
c. intermolecular epitope spreading
d. sympathetic senescence
e. linkage equilibrium

b. molecular mimicry

56

A(n) _____ is an epitope that is typically not accessible to the immune system but is revealed under inflammatory or infectious states.

a. cryptic epitope
b. molecular mimic
c. regulatory peptide
d. carrier
e. adjuvant

a. cryptic epitope

57

Amanda Chenoweth, 21 years of age, returned from a summer job as a pianist on a cruise ship where she was exposed daily to excessive sun; she developed a rash on her cheeks. She complained that her finger joints were stiff and painful, which made it difficult to play the piano, and that her hips became painful after sitting at the piano for long periods. Her blood sample tested positive for anti-nuclear antibodies and had decreased serum C3 levels. A urine albumin test showed elevated protein levels. A course of prednisone (an anti-inflammatory steroid) in combination with naprosyn (a nonsteroidal anti-inflammatory agent) was begun and her condition improved rapidly. What is the most likely cause and clinical name of her condition?

a. immune complexes fixing complement in kidney, joints, and blood vessels; systemic lupus erythematosus
b. consumption of seafood to which she was allergic; acute systemic anaphylaxis
c. deterioration of the central nervous system; multiple sclerosis
d. cartilage destruction by bone-cell enzymes; rheumatoid arthritis
e. autoantibodies against acetylcholine receptor at the neuromuscular junction; myasthenia gravis

a. immune complexes fixing complement in kidney, joints, and blood vessels; systemic lupus erythematosus

58

At 42 years old, Stephanie Goldstein developed occasional blurred and double vision, numbness and ‘pins and needles’ in her arms and legs (paresthesia), and bladder incontinence. After a month of these symptoms she went to her doctor, who sent her to the neurology specialist. An MRI scan revealed areas of demyelination in the central nervous system (CNS), and Stephanie was diagnosed with the autoimmune disease multiple sclerosis (MS). Which of the following best explains why some people are susceptible to the development of MS?

a. Regulatory T cells fail to activate autoreactive T cells in secondary lymphoid organs.
b. Apoptosis of autoreactive B cells occurs in the bone marrow during B-cell development.
c. Negative selection of autoreactive T cells occurs during T-cell development.
d. An immunodeficiency inhibiting somatic recombination of immunoglobulins and T-cell receptors
results in impaired lymphocyte development.
e. An inability to produce immunological tolerance toward CNS-derived constituents results in the generation of self-reactive lymphocytes.

e. An inability to produce immunological tolerance toward CNS-derived constituents results in the generation of self-reactive lymphocytes.

59

Anders Anderson, was seen by his pediatrician at 24 months old after a recent bout of diarrhea and vomiting. He had lost his appetite and complained that his stomach hurt. Anders was in the 5% centile for weight, had slender limbs, wasted buttocks, and a protuberant abdomen. Jejunal biopsy revealed abnormal surface epithelium, and villous atrophy with hyperplasia of the crypts. Which of the following would be a likely clinical finding in this patient?

a. urticarial rash
b. chronic wheezing
c. glomerulonephritis
d. low blood pressure
e. anti-gliadin IgA antibodies

e. anti-gliadin IgA antibodies

60

Seventeen-year-old Lisa Montague practiced piano for 3–4 hours each day while preparing for music college auditions. Some of her pieces required sustained arm-muscle activity and she began to find them hard to play, even though she had previously played them easily. When she also started to have difficulty swallowing and chewing, she told her mother, who took her to the emergency room, where the physician noticed drooping eyelids and limitation of ocular motility. An electromyogram detected impaired nerve-to-muscle transmission. Administration of pyridostigmine rapidly improved Lisa’s symptoms. Which of the following blood-test results would be most consistent with her condition?

a. elevated anti-acetylcholine receptor antibodies
b. elevated rheumatoid factor
c. elevated anti-myelin basic protein antibodies
d. elevated anti-nuclear antibodies
e. elevated anti-Rh antibodies.

a. elevated anti-acetylcholine receptor antibodies