Deck 12: Congenital and Acquired Immunodeficiencies

Question 1

Which of the following strategies would be expected to be LEAST effective in the prevention and/or treatment of AIDS?

A)Abstinence from intravenous drug use and unprotected sexual intercourse
B)Vaccination with recombinant gp120 protein to elicit antibodies against HIV
C)Chronic administration of a single non-nucleoside reverse transcriptase inhibitor
D)Chronic administration of highly active antiretroviral therapy (HAART)
E)Short-term administration of a nucleoside reverse transcriptase inhibitor to HIV-positive pregnant women during labor and the months preceding delivery

Answer 1

Vaccination with recombinant gp120 protein to elicit antibodies against HIV

Question 2

A 36-year-old man with a history of a positive anti-HIV antibody test comes to the clinic with fever, sore throat, nonproductive cough, and weight loss. This patient has had a partner for 8 years with whom he has frequently engaged in unprotected sexual intercourse. The partner is a healthy 29-year-old man who is HIV negative. The partner's relative "resistance" to HIV infection may be due to a loss-of-function mutation in which of the following proteins?

A)CD4
B)CD8
C)CCR5
D)Tumor necrosis factor (TNF)
E)NF-ĸB

Answer 2

CCR5

Question 3

A 7-month-old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. Careful examination of this infant reveals white plaques along the buccal mucosa, palate, and tongue, consistent with oral candidiasis (thrush). Analysis of blood cells reveals normal numbers of B cells and very few CD3⁺ cells. In addition, maternally-derived T cells, as determined by HLA typing, are detectable. The infant's mother reports that two of her three brothers died of infection as young children. Collectively, this presentation and history are most consistent with which of the following disorders?

A)X-linked agammaglobulinemia
B)X-linked severe combined immunodeficiency disease (X-linked SCID)
C)Common variable immunodeficiency
D)X-linked hyper-IgM syndrome
E)Adenosine deaminase deficiency (ADA)

Answer 3

X-linked severe combined immunodeficiency disease (X-linked SCID)

Question 4

Which one of the following is typically NOT associated with T cell immunodeficiencies?

A)Cancer
B)Viral infection
C)Autoimmunity
D)Infection with intracellular microbes
E)Infection with pyogenic bacteria

Question 5

All of the following have a direct role in mediating human immunodeficiency virus (HIV) entry into susceptible cells EXCEPT:

A)CD4
B)MHC class I
C)CCR5
D)CXCR4
E)Env

Question 6

A 3-year-old boy is taken to the pediatrician because of a nosebleed (epistaxis). He has a history of severe, recurrent sinopulmonary infection. Physical examination is remarkable for dry, red patches of skin (eczema) and multiple petechiae (tiny hemorrhagic spots). Laboratory findings include thrombocytopenia and reduced IgM levels. The boy's maternal uncle died of bleeding complications after an emergency appendectomy. Which of the following represents a curative therapy currently available for this patient?

A)Passive immunization with gamma globulin
B)Bone marrow transplantation
C)Treatment with corticosteroids
D)Enzyme replacement
E)Gene therapy

Question 7

All of the following may result in an acquired immunodeficiency EXCEPT:

A)Malnutrition
B)Treatment with corticosteroids
C)Disseminated cancer
D)Inherited defect in B cell maturation
E)Infection with human immunodeficiency virus (HIV)

Question 8

An 18-month-old girl is brought to the pediatrician because of recurrent upper respiratory tract infections. She has a fever, labored breathing, and a dry cough. Diagnostic tests confirm infection with Pneumocystis jiroveci. Serum studies are remarkable for negligible levels of IgG and IgA in the presence of high concentrations of IgM. The family history is unremarkable; in particular, the patient's three older brothers are in excellent health. This patient most likely carries a mutation in which of the following molecules?

A)CD18
B)CD40L
C)ZAP-70
D)B7
E)CD40

Question 9

A 7-month-old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. Based on the findings described, which one of the following should be excluded from the differential diagnosis?

A)X-linked agammaglobulinemia
B)X-linked severe combined immunodeficiency disease (X-linked SCID)
C)Common variable immunodeficiency
D)X-linked hyper-IgM syndrome
E)Adenosine deaminase deficiency (ADA)

Question 10

A 3-year-old boy is taken to the pediatrician because of a nosebleed (epistaxis). He has a history of severe, recurrent sinopulmonary infection. Physical examination is remarkable for dry, red patches of skin (eczema) and multiple petechiae (tiny hemorrhagic spots). Laboratory findings include thrombocytopenia and reduced IgM levels. The boy's maternal uncle died of bleeding complications after an emergency appendectomy. Which of the following is the most likely diagnosis?

A)Reticular dysgenesis
B)Wiskott-Aldrich syndrome (WAS)
C)Chédiak-Higashi syndrome
D)Ataxia-telangiectasia
E)DiGeorge syndrome

Question 11

A 36-year-old man with a history of a positive anti-HIV antibody test comes to the clinic with fever, sore throat, nonproductive cough, and weight loss. The patient has a high serum viral load, quantified by reverse transcriptase polymerase chain reaction (RT-PCR). This patient is LEAST likely to suffer from which of the following?

A)Kaposi's sarcoma
B)Pneumocystis jiroveci pneumonia
C)Encephalopathy
D)Cachexia
E)T cell lymphoma

Question 12

A 7-month-old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. Based on this family's history and clinical presentation, a mutation in which of the following genes is most likely to be found in this patient?

A)JAK3 kinase
B)Adenosine deaminase
C)Common cytokine receptor ƴ chain
D)RAG2
E)Purine nucleoside phosphorylase

Question 13

Which of the following is the most common known primary immunodeficiency with a prevalence of 1 in 700 white individuals?

A)X-linked agammaglobulinemia
B)Selective IgA deficiency
C)Common variable immunodeficiency
D)Chronic granulomatous disease
E)Chédiak-Higashi syndrome

Question 14

Which of the following patients is particularly susceptible to infection with Streptococcus pneumoniae, an encapsulated bacterium?

A)A 23-year-old man with malaise, rash, and diffuse lymphadenopathy consistent with early infection with human immunodeficiency virus
B)A 54-year-old woman receiving local corticosteroid injections for knee pain
C)A 35-year-old man with Hodgkin's disease and a deficient delayed-type hypersensitivity (DTH) response to Candida antigen
D)A 6-year-old boy with sickle cell anemia who had a splenectomy
E)A 77-year-old woman on chronic renal dialysis and a strict low-protein diet

Question 15

A 7-month-old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. This infant should NOT be given the measles-mumps-rubella (MMR) vaccination because:

A)The vaccine would have no effect because he is not susceptible to infection with measles, mumps, or rubella.
B)The vaccine would have no effect because he cannot mount an appropriate humoral response.
C)The vaccine could be dangerous because he is predisposed to develop a type I hypersensitivity response to the MMR vaccine.
D)The vaccine could be dangerous because vaccination with MMR would put him at risk for developing a fatal infection.
E)Vaccination with MMR is not contraindicated in his case and should be performed to prevent future infection.

Question 16

A 7-month-old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. The gene identified in this patient plays a critical role in receptor binding to all of the following ligands EXCEPT:

A)Interleukin (IL)-2
B)IL-4
C)IL-7
D)IL-12
E)IL-15

Question 17

A lymph node biopsy from a young boy with X-linked agammaglobulinemia is expected to show which of the following histologic features?

A)Marked perivascular lymphocytic infiltrate
B)Abundant polymorphonuclear inflammation
C)Reduced follicles and germinal centers
D)Nearly absent parafollicular cortical regions
E)Enlarged follicles

Question 18

Human immunodeficiency virus (HIV) is NOT a:

A)Herpesvirus
B)RNA virus
C)Enveloped virus
D)Retrovirus
E)Lentivirus