Immune Deficiency Disorders (Bayer)

Question 1

Which of the following is NOT a component of innate immunity?

A. Epithelial barriers

B. PRRs

C. Complement

D. Phagocytes

E. Lymphocytes

Answer 1

E. Lymphocytes are part of adaptive immunity (with the exception of NK cells, which are lymphocytes that are technically associated with innate immune response)

Question 2

These disorders comprise at least half of all primary immunodeficiency diseases:

A. Humoral

B. Phagocytic

C. Complement

D. Cellular

E. Combined

Answer 2

A.

From most to least:

humoral > combined > phagocytic > cellular > complement

Question 3

most common primary immune deficiency disease and is associated with recurrent sinopulmonary and GI infections, particularly Giardia

Answer 3

IgA deficiency

*also associated with celiac disease!

Question 4

Which of the following deficiencies is NOT generally associated with onset in the first year of life?

A. DiGeorge syndrome

B. Phagocytic defects

C. Common variable immunodeficiency

D. Complement defects

E. SCID

Answer 4

C. Onset of this one tends to occur from 18 months thru adulthood.

Question 5

Which of the following statements is FALSE?

A. People with complement deficiencies are susceptible only to recurrent bacterial infections.

B. People with any kind of PIDD are susceptible to bacterial infections

C. People with any kind of PIDD are susceptible to viral infections.

D. People with combined immunodeficiency will be suceptible to infection by any kind of organism.

E. People with humoral/antibody deficiencies are not susceptible to mycobacterial and fungal infections.

Answer 5

C. People with phagocytic and complement deficiencies will not clinically exhibit problems with viral infections, as they deal with the innate (extracellular) immune response and viruses are intracellular pathogens.

Question 6

Why do babies with SCID present as healthy and thriving until about 3 months of age?

Answer 6

They are born with an infusion of IgG from mom, which begins to wane by about 3 months, when they should be starting to make their own Ig.

Question 7

PIDD that is inhertied via x-linked autosomal recessive pattern and is marked by profound T cell dysfunction and B cell deficiency; clinical presentation is recurrent bacterial, fungal or viral infections

Answer 7

SCID

Question 8

treatment for SCID

Answer 8

HSCT, gene therapy, enzyme supplementation

Question 9

a subtype of SCID in which T cells are produced but not functional

Answer 9

Omenn Syndrome

Question 10

these pieces of DNA are extruded during T cell receptor gene rearrangement and are found circulating in the newborn infant’s blood in high numbers; they are the biomarker that is being evaluated in newborn screening

Answer 10

TRECs (T-cell Receptor Excision Circles)

Question 11

absence of this sign on a chest x ray may indicate SCID or DiGeorge syndrome

Answer 11

thymic shadow

Question 12

PIDD resuting from deletion in chromosome 22, and presents with CATCH:

• Cleft palate
• Absent T cells
• Tetany (seizures)
• Cardiac disease
• Hypocalcemia

Answer 12

DiGeorge syndrome

Question 13

Which of the following statements about Hyper-IgM syndrome is FALSE?

A. When it is inherited via x-linked pattern, there is a CD40L deficiency on T cells

B. When it is inherited as an autosomal recessive mutation, the problem is with CD40 on B cells

C. Failure of the CD40-CD40L interaction results in inability of B cells to undergo Ig class-switching

D. Treatment includes IVIG, HSCT and antimicrobial prophylaxis

E. All of the above are true

Answer 13

E

Question 14

Which of the following statements about x-linked agammaglobulinemia (XLA) is FALSE?

A. XLA has a unique susceptibility to enterovirus infections but no other viruses

B. XLA results from a problem with mature B cells that are unable to undergo class-switching

C. Infections begin at 4-6 months of life when maternal IgG wantes

D. All major classes of Ig are affected - treatment includes IVIG

E. Results in an inability to make antibody response to an antigen

Answer 14

B.

It actually results from the failure of the B cell lineage to develop because of a tyrosine kinase deficiency. This leads to absent B cells and no primary antibody response (T cells are fine!)

Question 15

this PIDD presents after 3 years of age with recurrent sinopulmonary, GI infections and severely decreased serum Ig in the absence of any other defined immunodeficiency state

Answer 15

common variable immunodeficiency

*this is a diagnosis of exclusion

Question 16

Which of the following statistics regarding complement deficiencies is FALSE?

A. C1q: carries >90% risk of early-onset SLE

B. C4: carries >50% risk of early-onset SLE

C. C3: most common hereditary complement deficiency

D. C2: increased risk of infection by encapsulated organisms

E. C5: increased risk of meningitis and bacteremia

Answer 16

C.

C2 is the most common hereditary deficiency, C3 is the most severe

Question 17

people with a NK cell deficiency are particularly susceptible to infections by what organisms?

Answer 17

HSV, HPV

Question 18

this disorder is clinically characterized by the lack of pus formation in tissues, resulting in impaired healing of wounds, and in infancy may present as delayed separation of cord

Answer 18

leukocyte adhesion deficiency 1 (most common of the LADs)

*caused by CD18 deficiency (an integrin that helps rolling leukocytes slow down and stick to the surface of endothelial cells for transmigration into the tissues)

Question 19

this disorder is usually x-linked and results from a defect in NADPH, which neutrophils need to form oxidative intermediates necessary for killing bacteria

Answer 19

chronic granulomatous disease

Question 20

Which of the following is NOT a catalse+ organism known to cause disease in chronic granulomatous disease patients?

A. Klebsiella and Pseudomonas

B. Staph aureus and B. cepacia

C. Candida and Aspergillus

D. Enteric organisms

E. Atypical mycobacteria

Answer 20

A. These organisms are catalase negative