Question 1

Leukocyte adhesion deficiency is caused by a defect in:

Accepted Answer

A)   CD3.
B)   CD18.
C)   CD19.
D)   CD25. B

Question 2

A 6-month-old baby has suffered from recurrent bacterial infections.Flow cytometry results indicate a lack of B cells but the presence of normally functioning T cells.Which is the most likely diagnosis?

Accepted Answer

A)   Severe combined immunodeficiency
B)   Common variable hypogammaglobulinemia
C)   DiGeorge syndrome
D)   Bruton's tyrosine kinase deficiency D

Question 3

A 1-year-old boy is evaluated for a suspected immune deficiency.He has a history since birth of eczema,recurrent rashes,and diarrhea.His white blood cell count (WBC)count is 6.75/uL (normal values: 5.0-10.8 × 103 uL)with a normal differential.Platelet count is 35,000 (normal values: 150,000-350,000/uL),and the platelets are small.His IgG is 750 mg/dL (normal values: 600-1,500 mg/dL).IgM is 30 mg/dL (normal values; 75-150 mg/dL).IgA is 475 mg/dL (normal values: 50-125 mg/dL).IgE is 750 mg/dL (10-50 mg/dL).The boy's blood is typed as O-positive,and he does not have anti-A or anti-B antibodies.Flow cytometry performed on his blood shows 11% CD19 (normal values: 5%-20%)and 50% CD3 cells (normal values: 60%-80%)with a normal ratio of CD4:CD8.T-cell function tests are abnormal.This boy most likely has:

Accepted Answer

A)   Bruton's tyrosine kinase deficiency.
B)   Wiskott-Aldrich syndrome.
C)   DiGeorge anomaly.
D)   ataxia telangiectasia. B

Question 4

The accumulation of immune complexes in renal glomeruli or joints (lupus-like syndromes)can be caused by a deficiency in the complement component:

Accepted Answer

A)   C5.
B)   MASP.
C)   properdin.
D)   C2.

Question 5

Which is true of selective IgA deficiency?

Accepted Answer

A)   It is invariably fatal.
B)   It is very rare.
C)   It mainly occurs in older adults.
D)   Patients may develop an anti-IgA antibody.

Question 6

Patients with recombinase activating gene 1 (RAG-1)or RAG-2 deficiencies have decreased numbers of:

Accepted Answer

A)   monocytes.
B)   granulocytes.
C)   lymphocytes. 
D)  all of the above.

Question 7

A patient's total IgG is in the normal range,but he suffers from recurrent infections with encapsulated bacteria such as Streptococcus pneumoniae and Haemophilus influenza.T-cell functions are all normal.What is the most likely cause of the infections?

Accepted Answer

A)   Tyrosine kinase deficiency
B)   Common variable immunodeficiency
C)   IgG subclass deficiency
D)   Selective IgA deficiency

Question 8

Which of the following diseases results in an acquired or secondary immunodeficiency?

Accepted Answer

A)   HIV infection
B)   Bruton's tyrosine kinase deficiency
C)   Leukocyte adhesion deficiency
D)   Wiskott-Aldrich syndrome

Question 9

A 9-month-old boy is suspected of having an immune deficiency because he had many recurrent infections with Streptococcus pneumoniae.Laboratory tests reveal a normal percentage of T cells and T-cell subsets but a lack of mature B cells and immunoglobulins.This boy most likely has:

Accepted Answer

A)   Wiskott-Aldrich syndrome.
B)   DiGeorge anomaly.
C)   X-linked agammaglobulinemia.
D)   chronic granulomatous disease.

Question 10

Defects in oxidative burst activity can be detected using flow cytometry by labeling patient neutrophils with:

Accepted Answer

A)   nitroblue tetrazolium.
B)   purified protein derivative.
C)   dihydrorhodamine.
D)   phytohemagglutinin.

Question 11

An autosomal-recessive disease characterized by the presence of abnormally large granules primarily affecting the function of lysosomes is known as:

Accepted Answer

A)   Chédiak-Higashi syndrome.
B)   X-linked lymphoproliferative disease.
C)   leukocyte adhesion deficiency.
D)   common variable immunodeficiency.

Question 12

A male baby who has suffered from persistent Candida fungal infections and several bouts of pneumonia before the age of 6 months is found to have some developmental problems as well as low-set ears.Laboratory testing reveals an absence of T cells.What is the most likely diagnosis?

Accepted Answer

A)   Selective IgA deficiency
B)   Common variable immunodeficiency
C)   Waldenström macroglobulinemia
D)   DiGeorge syndrome

Question 13

The most serious impairment of opsonization and antimicrobial defense is caused by a deficiency in complement component:

Accepted Answer

A)   C1q.
B)   factor B.
C)   C3.
D)   C5.

Question 14

Which of the following statements best describes common variable immunodeficiency?

Accepted Answer

A)   Symptoms appear in infancy.
B)   It is inherited as an X-linked recessive.
C)   It is invariably fatal for the patient.
D)   There is a deficiency of IgA, IgG, or both.

Question 15

A 7-month-old boy is seen by a specialist because of hypocalcemia,viral pneumonia,a history significant for recurrent diarrhea,and oral candidiasis.An x-ray reveals the lack of a thymic shadow.A likely diagnosis for this boy is:

Accepted Answer

A)   DiGeorge anomaly.
B)   Wiskott-Aldrich syndrome.
C)   ataxia telangiectasia.
D)   bare lymphocyte syndrome.

Question 16

The buildup of toxic purine metabolites that impair B- and T-cell proliferation is the result of a mutation in the gene coding for:

Accepted Answer

A)   recombinase activating gene 1 or 2.
B)   JAK3 kinase.
C)   mevalonate kinase.
D)   adenosine deaminase.

Question 17

A 9-month-old infant is seen by a physician because of a persistent skin infection.His white and red blood cell counts are normal.However,immunofixation electrophoresis indicates a low level of IgG.When the infant returns to the physician for a follow-up visit in a month,his IgG level has increased.What condition do these results indicate?

Accepted Answer

A)   Severe combined immunodeficiency
B)   Transient hypogammaglobulinemia
C)   Common variable immunodeficiency
D)   DiGeorge anomaly

Question 18

An autosomal-recessive form of severe combined immunodeficiency can be caused by a deficiency in:

Accepted Answer

A)   JAK3.
B)   Bruton's tyrosine kinase.
C)   mevalonate kinase.
D)   ataxia-telangiectasia kinase

Question 19

A child suspected of having an inherited humoral immunodeficiency disease is given a diphtheria/tetanus vaccine.Two weeks after the immunization,his level of antibody to the specific antigens is measured.Which result is expected for this patient if he does have this deficiency?

Accepted Answer

A)   Increased levels of specific antibody
B)   No change in the level of specific antibody
C)   An increase in IgG-specific antibody but not IgM-specific antibody
D)   Increased levels of nonspecific antibody

Question 20

A defective kinase needed for DNA repair and cell cycle control leads to involuntary muscle movements and dermal capillary swelling in which syndrome?

Accepted Answer

A)   Ataxia telangiectasia
B)   Wiskott-Aldrich
C)   Autoimmune lymphoproliferative
D)   Chediak-Higashi

Exam 19: Immunodeficiency Diseases