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USMLE Step 1 > Immunology > Flashcards

Immunology Flashcards

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USMLE® Step 1 flashcards
1
Q

What cell types are found in the lymph nodes?

A
  • Macrophages: filter and clean out lymphatic fluid
  • Lymphocytes: B and T-cells – activation, proliferation and differentiation
  • Plasma cells producing antibodies
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2
Q

What lymph nodes does the following area drain to?

Head and neck

A

Cervical/Neck

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3
Q

What lymph nodes does the following area drain to?

Upper extremity, breast and skin above umbilicus

A

Axillary nodes

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4
Q

What lymph nodes does the following area drain to?

Dorsolateral foot and posterior calf

A

Popliteal nodes

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5
Q

What lymph nodes does the following area drain to?

Thigh

A

Superficial inguinal nodes

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6
Q

What lymph nodes does the following area drain to?

Lungs

A

Hilar nodes

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7
Q

What lymph nodes does the following area drain to?

Trachea and esophagus

A

Mediastinal nodes

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8
Q

What lymph nodes does the following area drain to?

Stomach, liver, spleen and pancreas

A

Celiac nodes

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9
Q

What lymph nodes does the following area drain to?

Duodenum, jejunum, ileum and colon up to splenic flexure

A

Superior mesenteric nodes

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10
Q

What lymph nodes does the following area drain to?

Splenic flexure to upper rectum

A

Colonic nodes >> Inferior mesenteric nodes

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11
Q

What lymph nodes does the following area drain to?

  • Lower rectum to anal canal above the pectinate line
  • Bladder and prostate
  • Middle third of vagina
A

Internal iliac nodes

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12
Q

What lymph nodes does the following area drain to?

Testes and ovaries

A

Para-aortic nodes

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13
Q

What lymph nodes does the following area drain to?

Anal canal below the pectinate line

A

Superficial inguinal nodes

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14
Q

What lymph nodes does the following area drain to?

Kidneys

A

Para-aortic nodes

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15
Q

What lymph nodes does the following area drain to?

Scrotum

A

Superficial inguinal nodes

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16
Q

What genes code for MHC-I complexes?

A
  • HLA-A
  • HLA-B
  • HLA-C
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17
Q

What genes code for MHC-II complexes?

A
  • HLA-DR
  • HLA-DP
  • HLA-DQ
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18
Q

What are the T-cell surface markers?

A

All T-cells: CD3
T-helper cells: CD4, CD40L (binds to CD40 on B cells)
Cytotoxic T-cells: CD8

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19
Q

Which cells express MHC-I molecules?

A

All cells except RBCs

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20
Q

Which cells express MHC-II molecules?

A

ONLY antigen-presenting cells (APCs)

Therefore, APCs express both MHC-I and MHC-II complexes

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21
Q

What diseases are associated with HLA-B27?

A

Seronegative arthropathies (PAIR)

  • Psoriatic arthritis
  • Ankylosing spondylitis
  • Inflammatory bowel disease
  • Reactive arthritis/Reiter syndrome
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22
Q

What diseases are associated with HLA-DR3?

A
  • Diabetes mellitus type I
  • Systemic lupus erythematosus (SLE)
  • Graves disease
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23
Q

What diseases are associated with HLA-DR4?

A
  • Diabetes mellitus type I
  • Rheumatoid arthritis
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24
Q

What surface molecules are expressed by dendritic (antigen-presenting) cells?

A
  • MHC-I
  • MHC-II
  • B7 (CD80 or CD86): as a co-stimulatory molecule
  • CD40: to allow the binding Th-cell to stimulate other antigen presenting cells
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25
Q

What is the name of a dendritic cell that is scavenging for antigens?

A

Peripheral sentinel
>> Also known as “immature state” or “antigen-capturing state”

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26
Q

How do peripheral sentinels capture antigens?

A
  • Peripheral sentinels = immature dendritic cells/antigen-capturing dendritic cells
  • By any of these following 3 mechanisms:
    >> Phagocytosis
    >> Receptor-mediated endocytosis
    >> Pinocytosis
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27
Q

What is different in an antigen-presenting dendritic cell from an antigen-capturing dendritic cell/peripheral sentinel?

A
  • Increased expression of MHC-II
  • Increased expression of co-stimulatory molecules (B7 - CD80/CD86)
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28
Q

What are the two different types of dendritic cells?

A
  • Langerhans cell: epidermis
  • Interstitial dendritic cell: interstitium of all tissues except the brain
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29
Q

What is the pathology of Langerhans cell histiocytosis?

A

Proliferative disorder of Langerhans dendritic cells – functionally immature and do not efficiently stimulate primary T lymphocytes via antigen presentation

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30
Q

What are the tumour markers for Langerhans cell histiocytosis?

A
  • S-100
  • CD1a
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31
Q

What is the characteristic microscopic finding for Langerhans cell histiocytosis?

A

Birbeck granules (“tennis rackets”) on electron microscopy

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32
Q

How does Langerhans cell histiocytosis present?

A
  • Lytic bone lesions
  • Skin rash
  • Recurrent otitis media with a mass involving the mastoid bone
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33
Q

What are 3 cell types that are known for presenting antigens to T cells?

A
  • Macrophages
  • Dendritic cells
  • B cells

>> All three cell types have CD40 as one of their surface markers

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34
Q

What is the embryological origin of the thymus?

A

Third branchial/pharyngeal pouch

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35
Q

What is the action of IL-2?

A
  • Proliferation of cytotoxic T-cells
  • Proliferation of T1 helper cells
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36
Q

What is the action of IL-4?

A
  • Stimulates the differentiation to CD8+ cytotoxic T-cells
  • Stimulates activation and proliferation B-cells for antibody production
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37
Q

What is the action of IL-5?

A
  • Proliferation and activation of B-cells for antibody production
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38
Q

What is the action of IL-10?

A
  • To inhibit T1 helper cells from activating macrophages and cytotoxic T-cells
  • To inhibit macrophages
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39
Q

What is the action of IL-12?

A

To stimulate the differentiation of Th0 cells to Th1 cells

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40
Q

What is the action of IFN-gamma?

A
  • To stimulate macrophages for phagocytosis
  • Inhibits proliferation of Th2 cells
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41
Q

What cytokines activate Th1 cells, and what cytokines are produced by Th1 cells?

A

Activation: IL-12
Production: IL-2, IFN-gamma

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42
Q

What cytokines activate Th2 cells and what cytokines do they produce?

A

Activation: IL-4

Cytokins produced:

  • IL-2
  • IL-4
  • IL-5
  • IL-10
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43
Q

What cytokines activate macrophages, and what cytokines are produced by it?

A

Activation: IFN-gamma

Production:

  • IL-12 (stimulates Th0 differentiation to Th1, and activates NK cells)
  • IL-8 (neutrophil chemotactic agent)
  • Acute phase reactants: IL-1 (fever), IL-6 (fever) and TNF-alpha (septic shock)
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44
Q

What is the function of regulatory T-cells?

A
  • Inhibit B cells from producing antibodies
  • Inhibit Th cells and Tc cells
  • Produce IL-10 and other anti-inflammatory cytokines
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45
Q

How do cytotoxic T-cells kill?

A

Two mechanisms

  1. Induce the release of granyme, granulysin and perforin from cytotoxic granules
  2. Express Fas ligands to Fas receptors on infected cells
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46
Q

What cytokines enhance the activity of NK cells?

A
  • IL-2
  • IL-12
  • IFN-alpha
  • IFN-beta

>> IFN-alpha and beta also inhibit nearby cells of the virally infected cell to reduce viral protein synthesis as an anti-viral effect

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47
Q

What cytokines do NK cells release?

A
  • IFN-gamma: to activate macrophages
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48
Q

What cells do NK cells target?

A
  • Nonspecific activation signal on target cell
  • Cells with no Class I MHC on cell surface
    >> Sometimes virally-infected cells or cancer cells may downregulate their MHC class Is on their surfaces to “hide” from the immune system
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49
Q

How do NK cells kill?

A
  1. Release IFN-gamma to attract macrophages to the site for phagocytosis
  2. Target cells with no MHC class I molecules on their cell surfaces with granzyme and perforin release >> apoptosis induction
  3. Target cells with nonspecific signals with granzyme and perforin release >> apoptosis induction
  4. Antibody-dependent cell-mediated cytotoxicity (ADCC) with CD16 – binds to the constant region of antibodies >> induces apoptosis on cells coated with (opsonized) with antibodes — linkage with the adaptive immunity
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50
Q

What surface molecules do NK cells express?

A
  • CD16: regulates antibody-dependent cell-mediated cytotoxicity (ADCC)
  • CD56
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51
Q

What cells express CD16?

A
  • Natural killer cells (NK cells)
  • Neutrophils
  • Some macrophages/monocytes
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52
Q

Which cytokines inhibit Th1 cells? Which inhibit Th2 cells?

A
  • Th1 cells are inhibited by IL-10
  • Th2 cells are inhibited by IFN-gamma
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53
Q

Which cytokines are produced by Th1 cells? Which cytokines are produced by Th2 cells?

A

Th1 cells

  • IL-2: activates cytotoxic T-cells and Th cells
  • IFN-gamma: activates macrophages and inhibits Th2 cells

Th2 cells

  • IL-2: activates cytotoxic T-cells and Th cells
  • IL-4: activates Th2 cells and B cells
  • IL-5: activates B cells
  • IL-10: inhibits Th1 cells
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54
Q

Name the disease.

Anti-IgG Antibodies

A

Rheumatoid arthritis

>> Anti-IgG antibodies = rheumatoid factor (RF)

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55
Q

Name the disease.

Anti-centromere antibody

A

CREST scleroderma

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56
Q

Name the disease.

Anti-citrullinated protein antibodies (ACPA)

A

Rheumatoid arthritis

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57
Q

Name the disease.

Anti-Scl-70 antibody

A

Diffuse scleroderma

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58
Q

Name the disease.

Anti-histone antibody

A

Drug-induced lupus

>> SHIPP

  • Sulfonamides
  • Hydralazine
  • Isoniazid
  • Procainamide
  • Phenytoin
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59
Q

Name the disease.

Anti-dsDNA antibodies

A

Systemic lupus erythematosus (SLE), specific for lupus nephritis

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60
Q

Name the disease.

Anti-DNA topoisomerase antibodies

A

Diffuse scleroderma

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61
Q

Name the disease.

Anti-nuclear antibodies (ANA)

A

Systemic lupus erythematosus

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62
Q

Name the disease.

Anti-Jo-1 antibodies

A

Polymyositis and dermatomyositis

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63
Q

Name the disease.

Anti-Smith antibodies

A

Systemic lupus erythematosus (SLE)

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64
Q

Name the disease.

Anti-SSA (anti-Ro) antibodies

A

Sjogren’s syndrome

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65
Q

Name the disease.

Anti-U1-RNP antibodies

A

Mixed connective tissue disorder

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66
Q

Name the disease.

Anti-desmoglein antibody

A

Pemphigus vulgaris

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67
Q

Name the disease.

Anti-SSB (anti-La)

A

Sjogren’s syndrome

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68
Q

Name the disease.

Anti-acetylcholine receptor antibodies

A

Myasthenia gravis

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69
Q

Name the disease.

Anti-endomysial (anti-tissue transglutaminase) antibodies

A

Celiac disease

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70
Q

Name the disease.

Anti-gliadin antibodies

A

Celiac disease

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71
Q

Name the disease.

Anti-mitochondrial antibodies

A

Primary biliary cirrhosis

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72
Q

Name the disease.

Anti-smooth muscle antibodies

A

Autoimmune hepatitis

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73
Q

Name the disease.

Anti-glutamate decarboxylase

A

Type I Diabetes Mellitus

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74
Q

Name the disease.

Anti-thyrotropin receptor antibodies

A

Graves disease

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75
Q

Name the disease.

Anti-thyroid peroxidase (TPO) antibodies

A

Hashimoto’s thyroiditis

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76
Q

Name the disease.

Anti-thyroglobulin antibodies

A

Hashimoto’s thyroiditis, Graves disease

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77
Q

Name the disease.

Anti-basement membrane antibody

A

Goodpasture syndrome

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78
Q

Name the disease.

c-ANCA

A

Wegener’s disease: granulomatosis with polyangiitis

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79
Q

Name the disease.

p-ANCA

A
  • Microscopic polyangiitis
  • Pauci-immune crescentic glomerulonephritis
  • Churg-Strauss syndrome
80
Q

Name some live-attenuated vaccines.

A
  • MMR
  • VZV (varicella)
  • Yellow fever
  • Intranasal influenza
  • Sabin (oral) polio
  • Smallpox
81
Q

Name some killed vaccines.

A
  • Hepatitis A
  • Salk (injected) polio
  • Injected influenza
  • Rabies
82
Q

Name 4 diseases treated with passive immunization.

A

To Be Healed Rapidly

  • Tetanus infection/exposure
  • Botulinum infection/exposure
  • HBV infection/exposure
  • Rabies infection/exposure
83
Q

Which viral vaccines are potentially dangerous to patients with an egg allergy?

A
  • Influenza
  • Yellow fever

(Maybe MMR - but the egg amount is so tiny it is usually not clinically significant)

84
Q

What are the two most important opsonins in the body?

A
  • IgG
  • C3b
85
Q

What are the differential diagnoses for serum eosinophilia?

A

DNAAACP (DN-triple-A-CP)

  • Drugs: NSAIDs, penicillins/cephalosporins
  • Neoplasms
  • Allergies, asthma, allergic bronchopulmonary aspergillosis
  • Acute interstitial nephritis
  • Adrenal insufficiency
  • Parasites

+ HIV
+ Hyper-IgE syndrome
+ Hypereosinophilic syndrome
+ Coccidioidomycosis

86
Q

What are the four types of transplant rejection?

A
  • Hyperacute
  • Acute
  • Chronic
  • Graft-versus-host disease
87
Q

What is the function of the spleen?

A
  • Macrophages found in the spleen (marginal zone) destroy dysfunctional RBCs and encapsulated bacteria
  • Sequester and store platelets and red cells
88
Q

What are the possible causes of asplenia?

A
  • Autoinfarction in sickle cell anemia
  • Surgical asplenia (splenectomy) due to:
    >> Trauma
    >> Treatment for hereditary spherocytosis
89
Q

What are the microscopic signs of asplenia?

A
  • Howell-Jolly bodies (nuclear remnants)
  • Target cells
  • Thrombocytosis
90
Q

What is the monocyte derivative in:

Blood, alvoeli and intestines?

A

Macrophages

91
Q

What is the monocyte derivative in joints?

A

A cells

92
Q

What is the monocyte derivative in:

Connective tissue?

A

Langerhans cells/Histiocytes

93
Q

What is the monocyte derivative in:

The Liver?

A

Kupffer cells

94
Q

What is the monocyte derivative in:

The Kidneys?

A

Mesangial cells

95
Q

What is the monocyte derivative in:

The Brain?

A

Microglia

96
Q

What is the monocyte derivative in:

The Bone?

A

Osteoclasts

97
Q

What are the surface markers of macrophages?

A
  • MHC-I molecule
  • MHC-II molecule
  • B7 costimulatory molecules (CD80/86)
  • CD40
  • CD14
98
Q

What is the function of CD14 surface marker?

A

Binds to LPS endotoxin of gram-negative bacteria >> induces macrophages to generate acute phase cytokines

99
Q

What are the acute phase cytokines released by macrophages? What are their functions?

A
  • IL-1: pyrogenic (induces fever)
  • IL-6: pyrogenic (induces fever)
  • TNF-alpha: mediates septic shock
100
Q

What are the functions of macrophages?

A
  • Phagocytose and digest bacteria
    >> Motivated to phagocytose bacteria that are opsonized by IgG and C3b
    >> Generate oxygen free radicals using NADPH oxidase
  • Phagocytose cell debris and clean up wounds
  • Presents antigen
  • Release numerous cytokines: IL-1, IL-6, TNF-alpha + IL-8 + IL-12
  • Form multinucleate giant cells in granulomas
101
Q

What is the mechanism of action of cromolyn? What are its clinical uses?

A
  • Cromolyn inhibits degranulation of mast cells
  • Used as:
    >> Inhalers in asthmatics
    >> Nasal sprays in allergic rhinitis etc.
102
Q

What are the actions of IL-1, IL-2, IL-3, IL-4 and IL-5 respectively?

A

Hot T-BoneStEAk

  • IL-1: hot – fever/pyrogenic
  • IL-2: T-cells activation
  • IL-3: Bone marrow stimulation
  • IL-4: IgE and IgG production
  • IL-5: IgA production and eosinophils stimulation
103
Q

What cytokines are secreted by T-cells?

A
  • IL-2: stimulates proliferation of helper and cytotoxic T-cells
  • IL-3: supports bone marrow stem cell growth (similar to GM-CSF)
  • IL-4: stimulates B -cell proliferation and production of IgE/IgG, induces Th2 differentiation
  • IL-5: stimulates B-cell and eosinophils and production of IgA
  • IL-10: inhibits macrophages and Th1 cells
  • IFN-gamma: activates macrophages and inhibits Th2 cells
104
Q

What are the functions of IFN-alpha and IFN-beta?

A
  • Help neighbouring cells avoid infection
    >> Inhibit cellular protein synthesis
    >> Encourage ribonuclease activation that degreades viral mRNA
  • Activates natural killer (NK) cells
105
Q

What is the function of IL-8?

A

Neutrophil chemotaxis

106
Q

What are the three important neutrophil chemotactic agents?

A
  • IL-8 from macrophages
  • C5a from complement
  • LTB4 from the arachodonic acid pathway (COXes!)
107
Q

What is the function of IL-12?

A
  • Induces Th0 cells to differentiate into Th1 cells
  • Activates NK cells
108
Q

What is the mechanism of action aldesleukin?

A

Recombinant IL-2

109
Q

What are the clinical indications for aldesleukin?

A
  • Renal cell carcinoma
  • Metastatic melanoma
110
Q

What is the mechanism of action of filgrastim and sargramostim?

A

GM-CSF analogues >> stimulates bone marrow (similar to IL-3 action)

111
Q

What is the mechanism of action of oprelvekin?

A

IL-11 derivative
>> For treatment of thrombocytopenia

112
Q

What are the clinical indications for IFN-alpha?

A
  • Genital warts
  • Hepatitis B
  • Hepatitis C
  • Kaposi sarcoma
  • Hairy cell leukemia
  • Melanoma
113
Q

What are the clinical indications for IFN-beta?

A

Multiple sclerosis

114
Q

What are the clinical indications for IFN-gamma?

A

Chronic granulomatous disease

115
Q

When does hyperacute transplant rejection occur? What is the underlying mechanism?

A
  • Within minutes or hours >> usually within in the OT
  • An antibody-mediated Type II hypersensitivity reaction by pre-existing recipient antibodies
  • Highly preventable by screening and matching!
116
Q

When does acute transplant rejection occur? What is the underlying mechanism?

A
  • In weeks: within the first three months
  • Cell-mediated: cytotoxic T cells recognize foreign MHC-1 molecules and attack
  • Preventable and reversible by immunosuppressants
    >> Cyclosporin
    >> Tacrolimus
117
Q

When does chronic transplant rejection occur? What is the underlying mechanism?

A
  • Months to years
  • All transplants are bound to fail at some point in time >> hopefully long enough!
  • Mediated BOTH by T-cells and antibodies
    >> Cytotoxic T cells treat transplant cells as self-cells presenting non-self antigens
    >> Vascular damage and fibrosis
  • Unlike acute transplant rejection, chronic transplant rejection is NOT reversible.
118
Q

What is graft-versus-host disease?

A
  • Usually seen in bone marrow transplants
  • When grafted T cells (the new immune system from the donor) recognize the recipient’s cells as foreign and attack them
  • The host is recognized as “foreign” by the new bone marrow/immunity
119
Q

How does graft-versus-host disease present?

A
  • Maculopapular rash covering: neck and shoulders, ears and palms >> can blister and look like Stevens-Johnson syndrome
  • Hemolysis
  • Jaundice
  • Hepatosplenomegaly
  • Diarrhea
  • Nausea and vomiting

>> Time of onset varies

120
Q

What is the mechanism of action of cyclosporine?

A
  • Bind to cyclophilin
  • The cyclophilin-cyclosporine complex inhibits calcineurin
  • Blocks T-cell activation by PREVENTING IL-2 TRANSCRIPTION
121
Q

What are the unique side effects of cyclosporine?

A
  • Nephrotoxicity
  • Hypertension
  • Gingival hypertrophy
  • Hirsutism
122
Q

What is the mechanism of action of tacrolimus and pimecrolimus?

A
  • Binds to FK506 binding protein
  • The complex inhibits calcineurin
  • Blocks T-cell activation by PREVENTING IL-2 TRANSCRIPTION
123
Q

What are the indications for cyclosporine?

A
  • Transplant rejection prophylaxis
  • Psoriasis
  • Rheumatoid arthritis
124
Q

What are the indications for tacrolimus and pimecrolimus?

A
  • Topically for eczema
  • Systemic tacrolimus for transplant rejection prophylaxis
125
Q

What are the unique side effects of tacrolimus?

A
  • Similar to cyclosporine
  • + Neurotoxicity: headaches, paresthesia
  • No gingival hyperplasia or hirsutism
126
Q

What is the mechanism of action of sirolimus?

A
  • Binds to FKBP
  • Inhibits mTOR (mammalian target of rapamycin)
  • Prevents IL-2 SIGNAL TRANSDUCTION
  • Therefore blocks T-cell activation and B-cell differentiation
127
Q

What are the unique side effects of sirolimus?

A
  • Not much…
  • Anemia, leukopenia, thrombocytopenia
  • Insulin resistance
  • Hyperlipidemia

>> NOT NEPHROTOXIC

128
Q

What is the mechanism of action of azathioprine?

A
  • Antimetabolite precursor of 6-mercaptopurine
  • Blocks nucleotide synthesis
  • Inhibits lymphocyte proliferation
129
Q

What are the indications for azathioprine?

A
  • Transplant rejection prophylaxis
  • Rheumatoid arthritis
  • Crohn’s disease
  • Glomerulonephritis
  • Other autoimmune diseases
130
Q

What are the unique side effects of azathioprine?

A
  • Anemia, leukopenia and thrombocytopenia
  • Degraded by xanthine oxidase >> toxicity of both azathioprine and 6-MP will be increased by concomittant use of allopurinol
131
Q

What is the mechanism of action of mycophenolate?

A
  • Inhibits IMP dehydrogenase
  • Prevents the synthesis of guanine
  • Prevents rapid proliferation of B cells and T cells
132
Q

What are the indications for mycophenolate?

A
  • Transplant rejection prophylaxis
  • Lupus nephritis
133
Q

What is the mechanism of action of muromonab?

A
  • Monoclonal antibody
  • Binds to CD3 of all T cells
  • Blocks T-cell signal transduction
134
Q

What are the unique side effects of muromonab?

A

Cytokine release syndrome

135
Q

What is the mechanism of action of daclizumab?

A
  • Monoclonal antibody
  • Binds to CD25**, which is the **IL-2 receptor on activated T-cells
  • Prevents T-cell activation from response to IL-2 activation
  • Similar to the mechanism of sirolimus
136
Q

What is the mechanism of action of thalidomide?

A
  • Affects TNF-alpha
137
Q

What are the unique side effects of thalidomide?

A
  • Phocomelia
138
Q

What are the unique side effects of mycophenolate?

A
  • Increased risk for lymphoma
  • Teratogenic: increased risk for face and ear malformations, first trimester miscarriage
139
Q

Name three anti-TNF-alpha drugs/monoclonal antibody.

A
  • Infliximab
  • Adalimumab
  • Entanercept (not a monoclonal antibody – a decoy receptor)
140
Q

What are the indications for anti-TNF-alpha drugs?

A
  • Seronegative arthropathies
    >> Psoriatic arthritis
    >> Ankylosing spondylitis
    >> Inflammatory bowel disease-associated arthritis
    >> Reiter syndrome/reactive arthritis
  • Rheumatoid arthritis
141
Q

What is the mechanism of action of infliximab?

A

Anti-TNF-alpha monoclonal antibody

142
Q

What is the mechanism of action of abciximab?

A

GPIIb/IIIa inhibitor

143
Q

What is the mechanism of action of adalimumab?

A

Anti-TNF-alpha monoclonal antibody

144
Q

What is the mechanism of action of trastuzumab?

A

HER2/neu receptor monoclonal antibody
>> Also known as Herceptin

145
Q

What are the clinical indications for trastuzumab?

A
  • Breast cancer
  • Gastric cancer
146
Q

What is the mechanism of action of rituximab?

A

CD20 monoclonal antibody

147
Q

What are the clinical indications of rituximab?

A

Non-Hodgkin Lymphoma

148
Q

What is the mechanism of action of omalizumab?

A

Anti-IgE monoclonal antibody

149
Q

What are the clinical indications for omalizumab?

A

Poorly-controlled allergic asthma refractory to routine medical treatment

150
Q

What are the X-linked immunodeficiency syndromes - Name 4.

A

WAtCH

  • Wiskott-Aldrich syndrome
  • Bruton Agammaglobulinemia
  • Chronic granulomatous disease
  • Hyper-IgM syndrome
151
Q

Name two B cell deficiencies.

A
  • Bruton Agammaglobulinemia
  • Selective Immunoglobulin Deficiencies
152
Q

Name four T cell deficiencies.

A
  • Thymic aplasia (DiGeorge syndrome)
  • Chronic Mucocutaneous Candidiasis
  • Hyper-IgM syndrome
  • IL-12 receptor deficiency
153
Q

Name three combined B and T cell deficiencies.

A
  • Severe Combined Immunodeficiency (SCID)
  • Wiskott-Aldrich syndrome
  • Ataxia-Telangiectasia
154
Q

Name 4 phagocyte disorders.

A
  • Chronic Granulomatous Disease (CGD)
    >> Lack of NADPH oxidase
  • Chediak-Higashi Syndrome
    >> Defective phagocytic lysosome
    >> Defective LYST gene
  • Hyperimmunoglobulin E syndrome/Job syndrome
    >> Deficient IFN-gamma
    >> High levels of IgE and eosinophils
  • Leukocyte Adhesion Deficiency Syndrome
    >> Abnormal integrins
    >> Defective leukocytic extravasation
155
Q

What is the underlying pathophysiology of Bruton Agammaglobulinemia?

A
  • Defective tyrosine kinase >> B-cell deficiency
  • Low levels of ALL immunoglobulin
156
Q

What are the clinical features of Bruton Agammaglobulinemia?

A
  • Boy: X-linked disease
  • Recurrent bacterial infections after 6 months (after maternal breastfeeding usually stops)
157
Q

What is the most common type of selective immunoglobulin deficiency?

A

IgA

158
Q

How common is IgA selective immunoglobulin deficiency?

A

Common: 1/600 European descent

159
Q

What are the clinical features of IgA selective immunoglobulin deficiency?

A
  • Recurrent lung and sinus infections
  • Associated with atopy and asthma
  • Possible anaphylaxis to blood transfusions and blood products
160
Q

What is the underlying pathophysiology of DiGeorge syndrome?

A
  • Failure of 3rd and 4th pharyngeal pouchs to develop
    >> 3rd pouch: inferior parathyroid, thymus
    >> 4th pouch: superior parathyroid
161
Q

What are the clinical features of DiGeorge syndrome?

A

CATCH-22

  • Cardiac anomalies: TOF, truncus arteriosus
  • Abnormal facies
  • Thymic aplasia: no mature T-cells, absent thymic shadow
  • Cleft palate/lip
  • Hypocalcemia: due to lack of parathyroid development
    >> Chvostek’s sign: facial spasm upon tapping the cheek
    >> Trousseau’s sign: carpopedal sapsm after tightening a BP cuff on the arm
162
Q

What genetic mutation is thymic aplasia associated with?

A

Chromosome 22q11 deletion

163
Q

What is Chronic Mucocutaneous Candidiasis?

A

T cell dysfunction + Candida infections

164
Q

What is the treatment for chronic mucocutaneous candidiasis?

A

Ketoconazole

165
Q

What are the three types of Hyper-IgM syndrome?

A
  • X-linked: no CD40 ligand (a problem with T-cells)
  • Autosomal recessive: no CD40 (a problem with B-cells)
  • NEMO deficiency
166
Q

What infections are commonly associated with IL-12 deficiency?

A

Mycobacteria infections

167
Q

What is the underlying pathophysiology of severe combined immunodeficiency (SCID)?

A
  • Defect in early stem cell differentiation
  • Can be caused by at least 7 different gene defects
  • The most important gene defect to know: adenosine deaminase deficiency
  • Only has NK cells left
168
Q

What are the clinical features of severe combined immunodeficiency (SCID)?

A
  • Presentation triad:
    1. Severe recurrent infections
      >> Chronic mucocutaneous candidiasis
      >> Fatal or recurrent RSV, HSV, VZV, measles, flu and/or parainfluenza infections
      >> PCP pneumonia
    2. Chronic diarrhea
    3. Failure to thrive
  • NO thymic shadow on newborn CXR
169
Q

What are the clinical features of Wiskott-Aldrich Syndrome?

A

WAITER

  • W.A.: Wiskott-Aldrich Syndrome
  • Immunodeficiency: low IgM, high IgA
  • Thrombocytopenia
  • Eczema
  • Recurrent pyogenic infections
170
Q

What are the clinical features of ataxia telangiectasia?

A
  • Cerebellar ataxia
  • Poor smooth pursuit of moving target with eyes
  • Telangiectasias of the face at >5 years of age
  • Radiation sensitivity
  • Increased risk for acute leukemia and lymphoma

+/- increased AFP in children >8 months of age
>> Average age of death: 25 years old

171
Q

Which immunoglobulin is deficient in ataxia telangiectasia?

A

IgA

172
Q

What is the underlying pathophysiology of chronic granulomatous disease?

A
  • Lack of NADPH oxidase activitiy
  • Phagocytes cannot produce oxygen free radicals to kill bacteria
  • Results in impotent phagocytes who can eat but not kill
173
Q

Which organisms are patients with chronic granulomatous disease more susceptible to?

A

Those with catalase

  • Staphylococcus (aureus)
  • Escherichia coli
  • Klebsiella
  • Aspergillus
  • Candida
174
Q

How do we diagnose chronic granulomatous disease?

A

Nitroblue tetrazolium (NBT) test

  • Normal: yellow >> blue-black oxidation (positive test) – see picture
  • Chronic granulomatous disease: no colour change (negative test) >> due to lack of NADPH oxidase activity >> no oxidation
175
Q

How do we treat chronic granulomatous disease?

A
  • Prophylactic TMP-SMX
  • IFN-gamma
176
Q

What is the underlying pathophysiology of Chediak-Higashi syndrome?

A

Defective LYST gene >> defective phagocyte lysosomes

177
Q

What is the pathognomic histological feature of Chediak-Higashi syndrome?

A

Giant cytoplasmic granules in PMNs

178
Q

What are the clinical features of Chediak-Higashi syndrome?

A

Presentation triad:

  1. Partial albinism
  2. Recurrent respiratory tract and skin infections
  3. Neurologic disorders
179
Q

What is the underlying pathophysiology of HyperIgE syndrome (Job syndrome)?

A

Defective IFN-gamma production by T-cells >> impaired neutrophil chemotaxis

180
Q

What are the clinical features of HyperIgE syndrome?

A

Presentation triad:

  1. Eczema (E for IgE, E for eczema)
  2. Recurrent cold Staphylococcus aureus abscesses (boils!)
  3. Coarse facial features
    >> Broad nose
    >> Frontal bossing
    >> Deep-set eyes
    >> “Doughy” skin

+ Retained primary teeth >> 2 rows of teeth
+ High levels of IgE and eosinophils

181
Q

What is the underlying pathophysiology of leukocyte adhesion deficiency syndrome?

A

Abnormal integrins >> poor leukocyte extravasation

182
Q

What are the clinical features of leukocyte adhesion deficiency syndrome?

A

Delayed separation of the umbilical cord

183
Q

Name the cell type with the following surface protein.

CD4

A

T-helper lymphocytes

184
Q

Name the cell type with the following surface protein.

CD14

A

Macrophages

185
Q

Name the cell type with the following surface protein.

CD16

A

NK cells and macrophages

186
Q

Name the cell type with the following surface protein.

CD19

A

B lymphocytes

187
Q

Name the cell type with the following surface protein.

CD3

A

All T lymphocytes except NK cells

188
Q

Name the cell type with the following surface protein.

CD8

A

Cytotoxic T lymphocytes

189
Q

A child has an immune disroder in which there are repeated Staph abscesses. It is found that the neutrophils fail to respond because the chemotactic stimuli are deficient. What is the most likely diagnosis?

A

Hyperimmunoglobulin E syndrome (Job syndrome)

190
Q

Name the immune deficiency.

Anaphylaxis on exposure to blood products with IgA

A

Selective IgA (immunoglobulin) deficiency

191
Q

Name the immune deficiency.

Coarse facial features, abscesses and eczema

A

Hyper-IgE/Job syndrome

192
Q

Name the immune deficiency.

Thrombocytopenia, purpura, infections and eczema

A

Wiskott-Aldrich Syndrome

193
Q

Name the immune deficiency.

Delayed separation of the umbilicus

A

Leukocyte adhesion deficiency syndrome

194
Q

Name the immune deficiency.

Neuro defects, partial albinism, recurrent infections

A

Chediak-Higashi Syndrome

195
Q

Name the disorder.

Anti-endomysial antibodies

A

Celiac disease

196
Q

Name the disorder.

Anti-thyroglobulin antibodies

A

Hashimoto’s thyroiditis

197
Q

Name the disorder.

Anti-smooth muscle antibodies

A

Autoimmune hepatitis

USMLE Step 1 (14 decks)

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