Immune Deficiencies Defects

Question 1

X-Linked (Bruton) agammaglobulinemia

Answer 1

[BRUTON’s BTK] Defect in BTK, a tyrosine kinase gene leading to no B cell maturation. X-linked recessive (increased in Boys)

Question 2

Selective IgA deficiency

Answer 2

Unknown. most common primary immunodeficiency.

Question 3

Common variable immunodeficiency

Answer 3

Defect in B-cell differentiation. Many causes.

Question 4

Thymic aplasia (DiGeorge syndrome)

Answer 4

22q11 deletion; failure to develop 3rd and 4th pharyngeal pouches leading to absent thymus and parathyroids

Question 5

IL-12 receptor deficiency

Answer 5

Decreased Th1 response. Autosomal recessive.

Question 6

Autosomal dominant hyper-IgE syndrome (Job syndrome)

Answer 6

Deficiency of Th17 cells due to Stat3 mutation leading to impaired recruitment of PMNs to sites of infection

Question 7

Chronic mucocutaneous candidiasis

Answer 7

T-cell dysfunction. Many causes

Question 8

Severe combined immunodeficiency (SCID)

Answer 8

Several types including defective IL-2R gamma chain (most common, X-linked), adenosine deaminase deficiency (aut. rec.)

Question 9

Ataxia-telangiectasia

Answer 9

Defects in ATM gene leading to DNA double strand breaks and cell cycle arrest

Question 10

Hyper-IgM syndrome

Answer 10

Most commonly due to defective CD40L on Th cells = class switching defect; X-linked recessive

Question 11

Wiskott-Aldrich syndrome

Answer 11

Mutation in WAS gene (X-linked rec.); T cells unable to reorganize actin cytoskeleton

Question 12

Leukocyte adhesion deficiency (type 1)

Answer 12

Defect in LFA-1 integrin (CD18) protein on phagocytes; impaired migration and chemotaxis; aut. rec.

Question 13

Chediak-Higashi syndrome

Answer 13

Defect in lysosomal trafficking regulator gene (LYST). Microtubule dysfunction in phagosome-lysosome fusion; aut. rec.

Question 14

Chronic granulomatous disease

Answer 14

Defect of NADPH oxidase leads to decreased ROS and absent respiratory burst in PMNs; X-linked rec.