Immune Disorders

Question 1

C1 esterase inhibitor deficiency

Answer 1

cannot prevent complementation activation on self-cells (i.e. RBC) –> hereditary angioedema.

ACE inhibitors are contraindicated

Question 2

C3 deficiency

Answer 2

no opsonization
increased risk of recurrent pyogenic infections.
incr. TYPE III hypersensitivity

Question 3

C5-C9 deficiency

Answer 3

inability to have neutrophil chemotaxis. No MAC complex. recurrent Neisseria bacteremia. too much IgA –> DIC

Question 4

DAF (GP1 anchored enzyme) deficiency

Answer 4

inability to inhibit complement activation on RBCs –> paroxysmal nocturnal hemoglobinuria

Question 5

X-linked Bruton agammaglobulinemia

Answer 5

recurrent bacterial / enteroviral infections after 6 months (no maternal IgG)

Question 6

X-linked agammaglobulinemia findings

Answer 6

normal B cell count, deg. IgG, no lymph nodes / tonsils

Question 7

X-linked agammaglobulinemia pathophys

Answer 7

defected BTK (tyrosine kinase) –> no B cell maturation

Question 8

selective igA deficiency presentation

Answer 8

mostly Asymptomatic. Airway / GI infections. Autoimmune disease. Atopy, Anaphylaxis to IgA products. normal Ig G / IgM levels

Question 9

common variable immunodeficiency defect / presentation

Answer 9

acquired in 20s-30s. increased risk of autoimmune disease. bronchiectasis, lymphoma, sinopulmonary infections.

findings: dec. plasma cells / Igs

Question 10

thymic aplasia presentation

Answer 10

absent thymus / parathyroids –> low Ca2+ / PTH / T cells. recurrent viral / fungal infections, conotruncal abnormalities (tetralogy of Fallot, truncus arteriosus), tetany

Question 11

IL-12 receptor deficiency

Answer 11

dec. Th1 response / IFN-y. disseminated mycobacterial / fungal infections.

Question 12

AD hyperIgE syndrome

Answer 12

STAT3 mutation –> def. Th17 -> impaired neutrophil recruitment.

Question 13

FATED acronym + Job Syndrome (AD hyper IgE syndrome)

Answer 13

coarse Facies, noninflamed staph Abscesses, primary Teeth, incr. IgE, Derm problems (Eczema)

Question 14

chronic mucocutaneous candidiasis

Answer 14

T cell dysfunction –> no T-cell proliferation in response to candidda –> repeated candida infections

Question 15

severe combined immunodeficiency defects

Answer 15

1) IL-2r gamma chain (x-linked)

2) adenosine deaminase deficiency (AR)

Question 16

SCID presentation

Answer 16

1) recurrent viral, bacterial, fungal, protozal infections
2) failure to thrive, diarrhea, thrush
3) treatment: bone marrow transplant

Question 17

SCID findings

Answer 17

1) dec. T cell receptor exceision circles

2) absent thymic shadow, germinal ceners, T-cells on flow cytometry

Question 18

Ataxia-telangiectasia

Answer 18

defects in ATM –> dsDNA breaks –> cell cycle arrest:

1) ataxia
2) spider Angiomas
3) IgA deficiency

Question 19

ataxia telangiectasia findings

Answer 19

incr. AFP, dec. IgA,IgG,IgE

Question 20

Hyper IgM syndrome

Answer 20

defective CD40L on Th cells –> no class switching –> severe pyogenic infections + opportunistic infection (pneumocystis, cryptosporidium, CMV).

labs: lots of IgM. Low IgG, IgA, IgE

Question 21

wiskott-aldrich syndrome

Answer 21

T cells don’t recognize actin cytoskeleton.

1) thrombocytopenia + purpura
2) eczema
3) recurrent infections
4) increased risk of autoimmune disease / malignancy

Question 22

Leukocyte Adhesion Deficiency (type 1)

Answer 22

defective LFA-1 / Cd18 –> impaired migration, chemotaxis. –> recurrent bacterial infections. NO PUS. delayed umbilical cord separation (>30 days). increased neutrophils, but absence of neutrophils at site of infection

Question 23

chediak-Higashi syndrome defect

Answer 23

defect in lysosomal trafficking regulator gene (LYST) –> microtubule dysfunction in phagosome-lysosome fusion. autosomal recessive

Question 24

chediak-Higashi presentation + labs

Answer 24

1) recurrent pyogenic infections w/ stpah / strep
2) albinism
3) peripheral neuropathy
4) neurodegeneration
5) infiltrative lymphohistiocytosis

labs:

1) giant granules in neutrophils / platelets
2) pancytopenia
3) coagulation defects

Question 25

chronic granulomatous disease pathophys

Answer 25

defective NADPH oxidase –> dec. ROS / superoxide

Question 26

CGD presentation

Answer 26

incr. susceptibility to catalase + organisms (Pseudomonas, Listeria, Aspergillus, Candida, E Coli, S. Aureus, Serratia)

Question 27

CGD labs

Answer 27

abnormal dihydrorhodamine (flow cytometry).
nitroblue tetrazolium dye reduction test is negative