2.3 Primary Immunodeficiency

Question 1

DiGeorge Syndrome

Answer 1

22q11 deletion leads to the failure to form the 3rd and 4th pharyngeal pouch

Question 2

What will be the findings with DiGeorge Syndrome?

Answer 2

• Lack of thymus leading T cell deficiency
• Hypocalcemia due to a lack of parathyroids
• Abnormalities of the heart and great vessels

Question 3

Severe Combined Immunodeficiency

Answer 3

Defective cell mediated and humoral immunity

Question 4

What are the major etiologies of SCID?

Answer 4

• Cytokine receptor defects
• Adenosine deaminase dificiency
• MHC Class II deficiency

Question 5

What are SCID patients susceptible to?

Answer 5

• Viral infections
• Fungal infections
• Opportunistic infections

Question 6

What is the treatment for SCID?

Answer 6

Stem Cell Transplant

Question 7

X-linked agammgaglobulinemia

Answer 7

Complete lack of Ig due to disordered B cell maturation into plasma cells

Question 8

What is the mutation in X-linked agammgaglobulinemia?

Answer 8

Bruton Tyrosine Kinase mutation - signalling molecule

Question 9

What is the presentation with X-linked agammgaglobulinemia?

Answer 9

Recurrent enterovirus, bacterial and Giardia infections

Question 10

Common Variable Immunodeficiency

Answer 10

Low Ig due to B cell or helper T cell defects

Question 11

What is the presentation with CVID?

Answer 11

• Recurrent enterovirus, bacterial and Giardia infections

- Increased risk of autoimmune disease and lymphoma

Question 12

IgA Deficiency

Answer 12

Low serum and mucosal IgA

Question 13

What is the presentation of IgA deficiency?

Answer 13

Mucosal infections - this is the most common Ig deficiency

Question 14

What is IgA deficiency associated with?

Answer 14

Celiac Disease

Question 15

Hyper IgM Syndrome

Answer 15

Too much IgM due to mutated CD40L or CD40 receptor

Question 16

What is the purpose of the CD40 stimulus?

Answer 16

Second signal for the activation of CD4+ T cells to create IL-4/5 to cause B cell isotope switch

Question 17

What is the presentation of Hyper IgM Syndrome?

Answer 17

IgA/G/E are all low due to lack of switching so there will be recurrent mucosal and pyogenic infections

Question 18

Wiskott-Aldrich Syndrome Triad of Symptoms

Answer 18

• Thrombocytopenia
• Eczema
• Recurrent Infection

Question 19

Wiskott-Aldrich Syndrome Etiology

Answer 19

Due to a mutation in the Wiskott-Aldrich Protein

Question 20

What results from a C5-C9 deficiency?

Answer 20

Increased risk for Neisseria infections

Question 21

What results from C1 inhibitor deficiency?

Answer 21

Hereditary angioedema with edemoa of the skin - periorbital - and mucosal surfaces