Question 1

A generalized deficiency in the ability to mount delayed-type hypersensitivity (DTH)responses,as described in question 3,is called:&#10;A)Clinical atopy&#10;B)Clonal ignorance&#10;C)Clinical anergy&#10;D)Clonal deletion&#10;E)Seroconversion&#10;

Accepted Answer

A generalized deficiency in delayed-type hypersensitivity (DTH)responses is called clinical anergy.Note that clonal (or lymphocyte)anergy refers to the failure of clones of T or B cells to react to antigen.Anergy may be a mechanism of maintaining immunologic tolerance to self.Atopy refers to allergic disease.Clonal ignorance and clonal deletion are mechanisms of tolerance to antigens.Seroconversion refers to the appearance in the serum of antibodies specific for a particular antigen after infection or immunization.
Matching

Question 2

Match each of the following descriptions in questions with the appropriate disease (A-G).
Impaired CD4+ T cell development and activation,resulting in defective cell-mediated immunity and impaired T cell-dependent humoral immunity
H.

A)X-linked agammaglobulinemia
B)X-linked hyper-IgM syndrome
C)X-linked lymphoproliferative syndrome
D)Class II MHC deficiency
E)Chronic granulomatous disease (CGD)
F)Leukocyte adhesion deficiency-1 (LAD-1)
G)Leukocyte adhesion deficiency-2 (LAD-2)

Class II MHC deficiency

Accepted Answer

LAD-1 is a rare disorder in which integrins with the CD18 chain,such as LFA-1,are not expressed.Migration and function of neutrophils,monocytes,and lymphocytes are all impaired.

Question 3

Match each of the following descriptions in questions with the appropriate disease (A-G).
Impaired CD4+ T cell development and activation,resulting in defective cell-mediated immunity and impaired T cell-dependent humoral immunity
H.

A)X-linked agammaglobulinemia
B)X-linked hyper-IgM syndrome
C)X-linked lymphoproliferative syndrome
D)Class II MHC deficiency
E)Chronic granulomatous disease (CGD)
F)Leukocyte adhesion deficiency-1 (LAD-1)
G)Leukocyte adhesion deficiency-2 (LAD-2)

Class II MHC deficiency

Accepted Answer

Class II MHC deficiency is a form of severe combined immunodeficiency disease (SCID)caused by inherited mutations in genes encoding factors required for class II MHC transcription.The absence of class II MHC in the thymus results in a lack of positive selection and maturation of CD4+ T cells.

Question 4

All of the following may result in an acquired immunodeficiency EXCEPT:&#10;A)Malnutrition&#10;B)Treatment with corticosteroids&#10;C)Disseminated cancer&#10;D)Inherited defect in B cell maturation&#10;E)Infection with human immunodeficiency virus (HIV)&#10;

Accepted Answer

An inherited defect in B cell maturation is,by definition,a primary immunodeficiency,not an acquired immunodeficiency.In particular,abnormalities in B lymphocyte development and function result in deficient antibody production and increased susceptibility to infection by extracellular microbes.In contrast,malnutrition,treatment with corticosteroids,disseminated cancer,and infection with human immunodeficiency virus (HIV)would all result in acquired,or secondary,immunodeficiencies.Administration of corticosteroids to intentionally create an immunosuppressive state,such as in the treatment of inflammatory diseases or the prevention of tissue allograft rejection,is referred to as iatrogenic immunosuppression.

Question 5

Match each of the following descriptions in questions with the appropriate disease (A-G).
Impaired CD4+ T cell development and activation,resulting in defective cell-mediated immunity and impaired T cell-dependent humoral immunity
H.

A)X-linked agammaglobulinemia
B)X-linked hyper-IgM syndrome
C)X-linked lymphoproliferative syndrome
D)Class II MHC deficiency
E)Chronic granulomatous disease (CGD)
F)Leukocyte adhesion deficiency-1 (LAD-1)
G)Leukocyte adhesion deficiency-2 (LAD-2)

Class II MHC deficiency

Accepted Answer

X-linked lymphoproliferative syndrome is characterized by a severe CD8+ T cell response to Epstein-Barr virus (EBV),the virus that causes infectious mononucleosis.In a way,this is an example of a lethal exaggerated response to an infection,rather than a true immunodeficiency.

Question 6

In which of the following conditions would you be LEAST likely to see a robust delayed-type hypersensitivity (DTH)response to a Candida antigen skin challenge?&#10;A)X-linked agammaglobulinemia&#10;B)DiGeorge syndrome&#10;C)Selective IgA deficiency&#10;D)Common variable immunodeficiency&#10;E)Chronic granulomatous disease&#10;

Accepted Answer

A delayed-type hypersensitivity (DTH)response is an immune reaction in which T cell-dependent macrophage activation and inflammation cause tissue injury.The severity of the reaction to the subcutaneous injection of antigen is used as an assay for cell-mediated immunity.A deficient cutaneous DTH response to common microbial antigens,such as Candida antigens,suggests a T cell immunodeficiency.DiGeorge syndrome is a selective T cell deficiency caused by a congenital malformation that results in defective development of the thymus and other embryologically associated structures.In contrast,X-linked agammaglobulinemia,selective IgA deficiency,and common variable immunodeficiency are B cell immunodeficiencies.Chronic granulomatous disease is a congenital disorder in which phagocytes cannot generate free radicals and kill ingested microbes.

Question 7

Which of the following is not a valid explanation for why patients cannot eradicate HIV infections?&#10;A)HIV does not stimulate a CD8+ CTL response.&#10;B)HIV mutation rate is high,leading to evasion of immune recognition.&#10;C)A reservoir of latently infected cells invisible to the immune system is established rapidly after infection.&#10;D)CD4+ T cells are destroyed,impairing the immune response to the virus.&#10;

Accepted Answer

Patients infected with HIV typically mount a strong early CD8+ T cell response against viral antigens,and an antibody response to various HIV antigens.But for the reasons given in the other choices,these Reponses are not sufficient to eradicate the infection.

Question 8

Match each of the following descriptions in questions with the appropriate disease (A-G).
Impaired CD4+ T cell development and activation,resulting in defective cell-mediated immunity and impaired T cell-dependent humoral immunity
H.

A)X-linked agammaglobulinemia
B)X-linked hyper-IgM syndrome
C)X-linked lymphoproliferative syndrome
D)Class II MHC deficiency
E)Chronic granulomatous disease (CGD)
F)Leukocyte adhesion deficiency-1 (LAD-1)
G)Leukocyte adhesion deficiency-2 (LAD-2)

Class II MHC deficiency

Accepted Answer

Btk is required for pre-B cell receptor signaling and maturation from pre-B to immature B cells.In females carrying the mutated Btk gene on one X chromosome,the B cells that do mature have all inactivated the X chromosome carrying the mutant allele;thus,these individuals do not show a clinical phenotype.This disease is effectively controlled by injections of pooled gamma globulin.

Question 9

Match each of the following descriptions in questions with the appropriate disease (A-G).
Impaired CD4+ T cell development and activation,resulting in defective cell-mediated immunity and impaired T cell-dependent humoral immunity
H.

A)X-linked agammaglobulinemia
B)X-linked hyper-IgM syndrome
C)X-linked lymphoproliferative syndrome
D)Class II MHC deficiency
E)Chronic granulomatous disease (CGD)
F)Leukocyte adhesion deficiency-1 (LAD-1)
G)Leukocyte adhesion deficiency-2 (LAD-2)

Class II MHC deficiency

Accepted Answer

Chronic granulomatous disease (CGD)is a disorder of the innate immune system.The failure to generate reactive oxygen intermediates (free radicals)leads to persistent intracellular bacterial infections,with chronic T cell stimulation of macrophages and development of granulomas.

Question 10

Which one of the following is typically NOT associated with T cell immunodeficiencies?&#10;A)Cancer&#10;B)Viral infection&#10;C)Autoimmunity&#10;D)Infection with intracellular microbes&#10;E)Infection with pyogenic bacteria&#10;

Accepted Answer

B cell,not T cell,immunodeficiencies are associated with increased incidence of infection with pyogenic bacteria.In contrast,increased incidence of cancer is most often seen in T cell immunodeficiencies,because T cells are critical for surveillance against oncogenic viruses and the tumors they cause.Defects in cell-mediated immunity lead to infection by viruses and other intracellular microbes.Interestingly,certain immunodeficiencies are associated with increased incidence of autoimmunity;the mechanism for this phenomenon may reflect a deficiency of regulatory T cells that normally serve to maintain self-tolerance.

Question 11

The progression of HIV infection to AIDS is most directly due to which of the following?&#10;A)A loss of CD4+ T cells to numbers insufficient to prevent infections&#10;B)Reduction in serum IgG levels to levels insufficient to prevent infections&#10;C)Increased amount of virus in the blood&#10;D)Loss of weight&#10;E)Reduction in CD8+ CTLs specific for HIV&#10;

Accepted Answer

The answer of The progression of HIV infection to AIDS...

Question 12

Which molecules on the T cell surface are directly involved in HIV infection?&#10;A)CD4 and CD25&#10;B)CCR5 and CD25&#10;C)CD3 and CD4&#10;D)CD8 and CCR5&#10;E)CD4 and CCR5&#10;

Accepted Answer

The answer of Which molecules on the T cell surface...

Deck 8: Immunodeficiency-Diseases