immunodeficiencies

Question 1

caused by dysfunction of phagocytes

Answer 1

leukocyte adhesion deficiency
chediak-hagashi syndrome
chronic granulomatous disease

Question 2

leukocyte adhesion deficiency mechanism

Answer 2

defect in LFA-1 integrin (CD18) on phagocytes

leads to impaired neutrophil migration

Question 3

leukocyte adhesion deficiency clinical presentation

Answer 3

absence of neutrophils at infection site

delayed detachment of umbilical cord, no pus, impaired wound healing, recurrent skin and mucosal bacterial infections

Question 4

Chediak-Hagashi syndrome mechanism

Answer 4

defect in lysosomal trafficking regulator gene (LYST)

microtubule dysfunction in phagosome-lysosome fusion

Question 5

Chediak-Hagashi syndrome clinical presentation

Answer 5

partial albinims, peripheral neuropathy

giant granules in platelets and PMNs

Question 6

chronic granulomatous disease mechanism

Answer 6

defective NADPH oxidase (failure to generate oxygen radicals for respiratory burst in neutrophils)

Question 7

caused by dysfunction of B cells

Answer 7

x-linked agammaglobulinemia (Bruton’s agammaglobulinemia)
selective IgA deficiency
common variable immunodeficiency

Question 8

x-linked agammaglobulinemia mechanism

Answer 8

defect in BTK gene leading to lack of B cell maturation

Question 9

x-linked agammaglobulinemia clinical presentation

Answer 9

recurrent bacterial and enteroviral infections, absent/scanty lymph nodes and tonsils, absent B cells, decreased immunoglobulins

Question 10

common variable immunodeficiency mechanism

Answer 10

defect in B cell differentiation

Question 11

common variable immunodeficiency clinical presentation

Answer 11

low plasma cells, low immunoglobulins, delayed presentation (due to Ig’s from mother)

Question 12

caused by dysfunction of T cells

Answer 12

IL-12 receptor deficiency
Job syndrome
Chronic mucocutaneous candidiasis
Thymic aplasia (diGeorge syndrome)
Autoimmune polyendocrinopathy syndrome (APECED)
IPEX syndrome

Question 13

IL-12 receptor deficiency mechanism

Answer 13

leads to lack of Th1 cell response and low IFN-gamma

Question 14

Job syndrome mechanism

Answer 14

hyper-IgE syndrome

Th17 deficiency leads to an impaired ability to recruit neutrophils to the site of infection

Question 15

Job syndrome clinical presentation

Answer 15

FATED- abnormal facies, staph abscesses, retained primary teeth, hyper-IgE, dermatologic issues (eczema)
elevated IgE and eosinophils, decreased IFN-gamma

Question 16

chronic mucocutaneous candidiasis mechanism

Answer 16

T cell dysfunction (often a defect in IL-17 pathway)

Question 17

chronic mucocutaneous candidiasis clinical presentation

Answer 17

noninvasive candida infections of skin and mucous membranes

Question 18

thymic aplasia (diGeorge syndrome) mechanism

Answer 18

22q11 deletion leading to an absent thymus and parathyroids

Question 19

thymic aplasia (diGeorge syndrome) clinical presentation

Answer 19

CATCH-22- cleft palate, abnormal facies, thymic aplasia (T cell deficiency), conotruncal abnormalities, hypoglycemia
low Ca2+, absent thymic shadow, decreased T cells and PTH

Question 20

Autoimmune polyendocrinopathy syndrome (APECED) mechanism

Answer 20

mutation in AIRE gene leads to ineffective negative selection of T cells

Question 21

IPEX syndrome mechanism

Answer 21

deficiency of FOXP3 leading to non-functional regulatory T cells

Question 22

caused by dysfunction of B and T cells

Answer 22

Severe combined immunodeficiency (SCID)
ataxia-telangctasia
Wiskott-Aldrich syndrome
Hyper-IgM syndrome

Question 23

Severe combined immunodeficiency (SCID) mechanism

Answer 23

defective IL-2 receptor or defective adenosine deaminase (leads to buildup of purines which is toxic to lymphocytes)

Question 24

Severe combined immunodeficiency (SCID) clinical presentation

Answer 24

absent thymic shadow, absent T cells, absent germinal centers

Question 25

Ataxia-telangctasia mechanism

Answer 25

defect in the ATM gene (leads to an inability to repair dsDNA breaks- leads to cell cycle arrest)

Question 26

Ataxia-telangctasia clinical presentation

Answer 26

decreased IgA/IgG/IgE, lymphopenia | triad- ataxia (cerebellar atrophy), angiomas, IgA deficiency

Question 27

Wiskott-Aldrich syndrome mechanism

Answer 27

mutation in WASp gene (leads to inability of leukocytes and platelets to reorganize the actin cytoskeleton --> defective antigen presentation and platelets)

Question 28

Wiskott-Aldrich syndrome clinical presentation

Answer 28

WATER- thrombocytopenia, eczema, recurrent pyogenic infections elevated IgE and IgA

Question 29

Hyper IgM syndrome mechanism

Answer 29

mutated CD40L on helper T cells, leads to a lack of class switching

Question 30

Hyper IgM syndrome clinical presentation

Answer 30

increased IgM, decreased IgG/IgA/IgE, absence of germinal centers

Question 31

cause by type 2 hypersensitivity reactions

Answer 31

grave's disease myasthenia graves autoimmune hemolytic anemia goodpasture's syndrome

Question 32

grave's disease mechanism

Answer 32

autoantibodies that bind TSH receptor

Question 33

myasthenia gravis mechanism

Answer 33

autoantibodies that bind acetylcholine receptor

Question 34

autoimmune hemolytic anemia mechanism

Answer 34

autoantibodies that bind RBC surface antigens

Question 35

caused by type 3 hypersensitivity reactions

Answer 35

rheumatoid arthritis | systemic lupus erythematosus (SLE)

Question 36

rheumatoid arthritis mechanism

Answer 36

rheumatoid factor IgG complexes

Question 37

systemic lupus erythematosus (SLE) diagnosis

Answer 37

anti-dsDNA is specific for diagnosis | anti-nuclear antibodies (ANA) also positive

Question 38

caused by type 4 hypersensitivity reactions

Answer 38

type 1 DM multiple sclerosis hashimoto's thyroiditis sjogren syndrome

Question 39

type 1 DM mechanism

Answer 39

critical role of CD8+ T cells; pancreatic beta cell antigen

Question 40

multiple sclerosis mechanism

Answer 40

critical role of CD4+ T cells