Primary immunodeficiency/Immunology

Question 1

Features of IgA deficiency (4)

Answer 1

Asymptomatic
Autoimmune disease
Atopy
Anaphylaxis to IgA in blood products

increased risk for airway and GI infections (giardiasis)

Question 2

Difference between morphology of lymph nodes in X-linked agammaglobulinemia and SCID

Answer 2

X-linked agammaglobulinemia: absence of primary follicles, germinal centers. Abscence of B cells
SCID: Absence of germinal centers but primary follicles present. Absence of T cells

Question 3

Features of X-linked agammaglobulinemia (6)

Answer 3

defect in BTK
no B cell maturation
in Boys (X-linked recessive)
absent of LN and tonsils (no primary follicles and germinal centers)
Live vaccines contraindicated
Recurrent infections 6mths after birth

Question 4

Features of CVID (2)

Answer 4

Defect in B cell differentiaion

Low in plasma cells and Ig

Question 5

Features of Digeorge syndrome (3)

Answer 5

• 22q11 microdeletion
• failure to develop 3th, 4th pharyngeal pouch (absence of thymus, parathyroid)
• CATCH-22: conotruncal cardiac abnormality, abnormal facies, thymic hypoplasia (T cell deficiency), cleft palate, Hypocalcemia

Question 6

Features of Job syndrome (4)

Answer 6

• STAT3 mutation
  -Deficiency in Th17 cells
  -Impaired neutrophils recruitment
  -learn ABCDEF to get a JOB!
  Abscess (cold staph), Baby teeth retained, Coarse facies, Dermatological prob (eczema), IgE raised, Fractures of bones (pathological)

Question 7

Subtypes of SCID? (2) Common pathological pathway of both subtypes? Features of SCID. (4)

Answer 7

X-linked rec.: IL-2R gamma chain defect
auto. rec.: adenosine adeaminase (ADA) deficiency
both causing RAG mutation (VDF recombination defect)

• Absence of thymic shadow, germinal center (lymph node, T cells
• lack of T cell receptor excision circle

Question 8

Features of ataxic telangiectasia (5)

Answer 8

-5As: Ataxia (cerebellar), spider Angioma (telangiectasia), IgA deficiency, ATM gene defect, Autosomal recessive

Question 9

Features of hyper IgM syndrome

Answer 9

high IgM, low other Ig.

Failure to make germinal center

Question 10

Features of hyper IgM syndrome (4)

Answer 10

• CD40L defective (cant class switch)
• X-linked recessive
• high IgM, low other Ig.
• Failure to make germinal center

Question 11

Features of Wiskott-Aldrich syndrome (5)

Answer 11

• mutation in WAS gene
• defective antigen presenting
• X-linked recessive
• WATER: Wiskott-Aldrich, Thrombocytopenia, Eczema, Recurrent infections
• the only 2 vowels in WATER: AE (high in IgA, IgE)

Question 12

Features of chronic granulomatous disease (5)

Answer 12

• lack of NADPH oxidase (cant form ROS)
• X-linked recessive
• susceptible to catalase + organisms and formation of granulomas
• dihydrorhodamine test abnormal
• nitroblue tetrazoline test fail

Question 13

Features of Chediak Higashi syndrome (5)

Answer 13

-LYST gene mutation
-microtubule dysfunction causing lysosome and phagosome cant fuse
Think of Adamwise Lam (4): partial albinism, lymphohistiocytosis (too many WBC that half body turn white), progressive neurodegeneration, peripheral neuropathy,
-Giant granules
-Pancytopenia

Question 14

Leukocyte adhesion deficiency

Answer 14

-defect in LFA-1 integrin (Leukocyte’s Fucked Adhesion) (CD18)
-impaired neutrophil migration and chemotaxis
Delayed umbilical cord sloughing
No pus, dysfunctional neutrophils but high neutrophils in blood

Question 15

State function of IL1 to IL12, (x IL7, 9, 11), TN-alpha, IFN-gamma

Answer 15

IL1: HOT
IL2: T
IL3: bone
IL4: 2 B.E.G. 4 help (helper 2)
IL5: 5 B.A.E. (eosinophils)
IL6: increase aKute phase protein production
IL8: neutrophil chemotaxis
IL10: anti inflammatory
IL12: I want (1) 2 Help NK (helper 1)
TNF-alpha: activates leukocytes leakage and recruitment, cause cachexia in malignancy
IFN-gamma: activate NK, activate macrophages for granuloma formation

Question 16

Chronic mucocutaneous candidiasis

Features (2)

Answer 16

Multiple, recurrent candidiasis

Defect in Th17 cells, causing low in IL-17