Exam #3: Immunodeficiencies

Question 1

When should you be suspicious for an immunodeficiency?

Answer 1

• Unusually frequent, severe, resistant infections

- Refractory to treatment compared to patients of similar age & exposure risk

Question 2

What is the difference between a primary & secondary immunodeficiency?

Answer 2

Primary= genetically determined

• Genetic defects in B or T lymphocytes
• Usually presents between 6 months & 2 years

Secondary= consequences of cancer, other infections, malnutrition, drugs

Question 3

What are the clinical manifestations of primary immunodeficiencies?

Answer 3

• Recurrent infections

- Failure to thrive

Question 4

What is the consequence of an ADA deficiency in lymphocyte development?

Answer 4

No pro-B or T cells

Question 5

What is defect in lymphocyte development seen in X-Linked Agammaglobulinemia?

Answer 5

Pre-B cells are unable to mature

Question 6

What is defect in lymphocyte development seen in Hyper IgM-Syndrome?

Answer 6

Lack of:

• CD40L
• Activation induced deaminase

*****Immature B-cells can mature into IgM but NOT other isotypes

Question 7

What is defect in lymphocyte development seen in X-Linked SCID?

Answer 7

Cytokine gamma chain= pro T-cell cannot become immature T-cell

Question 8

What is defect in lymphocyte development seen in Di George Syndrome?

Answer 8

Immature T-cell cannot mature

Question 9

What is X-Linked Agammaglobuliemia of Burton?

Answer 9

• X-linked recessive disorder of males caused by mutation in Burton’s Tyrosine Kinase (BTK)gene
• Responsible for B-cell maturation via pro/pre-B cell signal transduction

*****B-cells don’t mature & can’t produce antibodies

Question 10

What is agammaglobulinemia?

Answer 10

No antibody production i.e. absence of mature B-cells in the blood

Question 11

When does Burton’s Agammaglobulinemia onset?

Answer 11

After maternal antibodies have been depleted, which is ~6months

Question 12

What is the clinical presentation of Burton’s Agammablobulinema?

Answer 12

• Recurrent sinusitis
• Oropharyngeal
• Respiratory infections

*****All due to pyogenic bacteria that would normally be opsonized by circulating antibodies

Question 13

What are the three major pyogenic bacteria that are opsonized by circulating antibodies?

Answer 13

1) Staphylococcus aureus
2) Streptococcus pneumoniae
3) H. Influenza

Question 14

What are the viral & protozoal infections are patients with Burton’s Agammaglobulinemia are susceptible to?

Answer 14

Enteric viruses & giardia lamblia

Question 15

What vaccination is especially dangerous for patients with Burton’s Agammaglobulinemia?

Answer 15

Polio from live vaccine–>leads to paralytic polio

Question 16

When does Burton’s Agammaglobulinemia onset?

Answer 16

After maternal antibodies have been depleted

Question 17

What is the treatment for Burton’s Agammagloulinemia?

Answer 17

Parenteral immuoglobulin replacement

Question 18

What is Common Variable Immunodeficiency?

Answer 18

Variable group of disorders that occur later in life

Question 19

What are the mechanisms of Common Variable Immunodeficiency?

Answer 19

The mechanisms of CVID are variable and include:

1) Intrinsic B-cell defects
2) Abnormal T-cell signaling to B-cells

*****Both lead to an inability of B-cells to become plasma cells

Question 20

What are the lab findings associated with Common Variable Immunodeficiency?

Answer 20

Hypogammaglobulinemia, usually all antibody classes but occasionally isolated IgG

Question 21

What are the clinical features of Common Variable Immunodeficiency?

Answer 21

• Recurrent bacterial infections of the sinuses & respiratory tract
• Increased enteroviral infections & chronic diarrhea due to Giardia Lamblia infection
• Paradoxical increase in autoimmune disorders

Question 22

What are patients with Common Variable Immunodeficiency at increased risk for?

Answer 22

• Autoimmune disorders
• B-cell Lymphoma
• Gastric Cancer

Question 23

What are the lab findings associated with Common Variable Immunodeficiency?

Answer 23

Hypogammaglobulinemia, usually all Ab but occasionally isolated IgG

Question 24

What is selective IgA deficiency?

Answer 24

Isolated IgA deficiency in which infected individuals have low levels of serum & secretory IgA

Question 25

What is the most common immunodeficiency?

Answer 25

Selective IgA deficiency (European)

Question 26

What is acquired IgA deficiency associated with?

Answer 26

• Measles
• Toxoplasmosis
• Other viral infections

Question 27

Describe the clinical features of Selective IgA Deficiency.

Answer 27

IgA is the major Ig in secretions; thus, infections are common in the:

1) Respiratory
2) GI
3) GU tracts

Question 28

What do you need to remember about patients with Selective IgA Deficiency?

Answer 28

Blood transfusion with blood containing normal levels of IgA can induce anaphylaxis