2.3 - Primary immunodeficiency

Question 1

digeorge syndrome is due to failure of which pharyngeal pouches to form?

Answer 1

3rd and 4th

Question 2

digeorge syndrome is due to a microdeletion in ________

Answer 2

22q11

Question 3

how does digeorge syndrome present?

Answer 3

• T cell deficiency
• hypocalcemia
• abnormalities of heart, great vessels, face

Question 4

what are the 3 etiologies of SCID?

Answer 4

• cytokine receptor defects
• ADA deficiency
• MHC II deficiency

Question 5

how do cytokine receptor defects lead to SCID?

Answer 5

signaling is necessary for proliferation and maturation of B and T cells

Question 6

how does ADA deficiency lead to SCID?

Answer 6

buildup of adenosine and deoxyadenosine is toxic to lymphocytes

Question 7

how does MHC II deficiency lead to SCID?

Answer 7

MHC II is necessary for CD4 Th cell activation and cytokine production

Question 8

what is the cause of X linked agammaglobulinemia?

Answer 8

disordered B cell maturation - lack of Ig

Question 9

what enzyme is mutated in X linked agammaglobulinemia?

Answer 9

Bruton tyrosine kinase

Question 10

a 6 month old child presents with recurrent bacterial, enterovirus, and giardia infections - diagnosis?

Answer 10

X linked agammaglobulinemia (possibly CVID)

Question 11

X linked agammaglobulinemia leads to susceptibility from what types of infections?

Answer 11

• bacterial
• enterovirus
• giardia

Question 12

why is there low Ig in CVID?

Answer 12

B cell or Th cell defects

Question 13

CVID predisposes to what types of diseases?

Answer 13

• autoimmune

- lymphoma

Question 14

what is the defect in hyper IgM syndrome?

Answer 14

• mutated CD40L (on Th cells) or CD40 receptor (on B cells)

Question 15

why is so much IgM made in hyper IgM syndrome?

Answer 15

• first activation signal of B cell activation is intact - a lot of IgM gets made
• class switching is defective due to lack of second signal

Question 16

patients with hyper IgM syndrome are susceptible to what type of infections?

Answer 16

pyogenic

Question 17

• thrombocytopenia
• eczema
• recurrent infections

diagnosis?

Answer 17

wiskott aldrich syndrome

Question 18

wiskott aldrich syndrome is due to a mutation in the ______ gene and its inheritance is ___________

Answer 18

• WASP

- X linked

Question 19

what is the major cause of death in wiskott aldrich syndrome?

Answer 19

bleeding

Question 20

which arm of immunity is defective in wiskott aldrich syndrome - humoral / cellular / both?

Answer 20

both

Question 21

C1 inhibitor deficiency results in what disease?

Answer 21

hereditary angioedema