Immunodeficiencies Flashcards Preview

USMLE Step 1 > Immunodeficiencies > Flashcards

Flashcards in Immunodeficiencies Deck (18):
1

X-linked (Bruton) Agammaglobinemia

B-cell
- BTK (tyrosine kinase), u-hc, Iga, BLNK
- X-linked
- No B-cell maturation (increased pro-B-cells)
- Rec. bact/enterovirus/giardia after 6mo
- No peripheral B-cells, Decreased Ig (all), absent/scanty LN's and tonsils
- Avoid live vaccines

2

Selective IgA deficiency

B-cell
- Unknown (most common primary ID)
- Asymptomatic (most)
- Airway and GI
- Autoimmune
- Atopy
- Anaphylaxis with IgA containing blood products
- Associated with celiac disease

3

Common variable immunodeficiency

B-cell
- Many causes
- Defective B-cell differentiation
- Acquired in 20s-30s
- Autoimmune
- Bronchiectasis, Lymphoma, Sinopulmonary infections
- Decreased plasma cells and Ig's
- Low to normal B-cells

4

Thymic aplasia (DiGeorge Syndrome)

T-cell
- 22q11 del (failed 3rd/4th pouches)
- Absent thymus and parathyroid
- Tetany, rec. viral/fungal, conotruncal abnormalities (TOF, TA)
- Decreased T-cells, TRECs, PTH, Ca
- Absent thymic shadow (CXR)

5

IL-12 receptor deficiency

T-cell
- Decreased Th1 response
- AR
- Disseminated mycobacterial and fungal (possible post-BCG vaccine)
- Decreased IFN-y

6

AD hyper-IgE syndrome (Job syndrome)

T-cell
- STAT3 mutation (decreased Th17)
- Impaired recruitment if neutrophils to site of infect
- FATED (coarse Facies, cold (noninflammed) staph. Accesses, primary Teeth, hyper-IgE, Dermatological (eczema), bone fractures
- Increased IgE, decreased IFN-y, eosinophilia

7

Chronic mucocutaneous candidiasis

T-cell
- Many causes
- Noninvasive candida albicans of skin/mucosa
- T-cells don't respond to candida Ag

8

Transient Hypogammaglobinemia of Infancy

B-cell
- IgM, IgG or IgA greater than 2SD below mean
- Normal Ab production to polio and HA vaccines
- intact cellular immunity
- rec. non-serious infections

9

IFN-y receptor def

T-cell
- Disseminated TB early in life (inc. from BCG)

10

Severe Combined Immunodeficiency (SCID)

B and T cell
- IL-2R gamma chain (X-linked), ADA (AR), MHC-II def, JAK3 (AR), IL-7R alpha chain, IKBKB
- Failure to thrive, chronic diarrhea, thrush
- Rec. viral, bact, fungal, protozoal
- Vaccine susceptible
- Decreased TRECs
- Absent thymic shadow, germinal centres, T-cells
- Rx: BM transplant, isolation, gene Tx

11

Ataxia-telangiectasia

B and T cell
- ATM gene
- Failed ds break repair (DNA) causing cell cycle arrest
- Ataxia (cerebellar), spider Angiomas, IgA def.
- Increased AFP
- Decreased IgA, IgG, IgE
- Lymphopenia and cerebellar atrophy

12

Hyper-IgM syndrome

B and T cell
- Defective: CD40L (XR), CD40 (AR)
- Class switching defect
- Severe pyogenic infections early in life
- Opportunistic infections: Pneumocystis, Cryptosporidium, CMV
- Increased IgM
- Decreased IgG, IgA, IgE

13

Wiskott-Aldrich syndrome

B and T cell
- WAS gene (XR)
- T-cells unable to reorganize actin cytoskeleton (necessary for APC - Tcell synapse)
- WATER (Wiskott-Aldrich: Thrombocytopenic purpura, Eczema, Reccurent infections)
- Increased risk of autoimmune and malignancy
- Decreased to normal IgG, IgM
- Increased IgE, IgA
- Fewer and smaller platelets

14

Leukocyte adhesion deficiency (type 1)

Phagocyte
- Defect in LFA-1 integrin (CD18)
- Impaired migration and chemotaxis
- Autosomal recessive
- Rec. bacterial skin and mucosa infections
- No pus formation
- Impaired wound healing
- Delayed separation of umbilical cord (>30days)
- Increased neutrophils (absent at infection site)

15

Leukocyte adhesion deficiency (type 2)

Phagocyte
- RARE, E-selectin ligands (Sialyl-Lewis X or CD15s) absent (no rolling)
- E-selectin contains fucose: if defect with de novo give oral fucose, if defect with fucose transport to golgi, oral does nothing)
- mental retard, short, distinctive facies

16

Chediak-Higashi syndrome

Phagocyte
- Defect: lysosomal trafficking regulator gene (LYST) [AR]
- Microtubule dysfnc in phagosome-lysosome fusion
- Rec. pyogenic infections w/ staph and strep
- Partial albinism
- Peripheral neuropathy
- Progressive neurodegeneration (+ vision)
- Infiltrative lymphohistiocytosis
- Giant granules in granulocytes and platelets
- Pancytopenia, mild coagulation defects, neutropenia

17

Chronic Granulomatous disease

Phagocyte
- NADPH oxidase defect (XR most common)
- Susceptible to catalase positive (Need PLACESS: Nocardia, Pseudomonas, Listeria, Aspergillus, Candida, E. coli, S. aureus, Serratia)
- Acne, gingivitis, massive LAD, 50% have chronic gut inflammation similar to Chron's
- Abnormal dihydrorhodamine (flow cytometry) test
- Nitroblue tetrazolium dye reduction test is negative (colourless)

18

MPO deficiency

Phagocyte
- Most asymptomatic
- increased candida infection
- NBT test positive (blue)