Usmle Step 1 Flashcards - Immunology

Front 1

What's found in the medulla of the thymus?

Back 1

Mature T cells
Epithelial reticular cells (that express self antigens)
Hassall's corpuscles

Front 2

Histo appearance of thymic cortex vs medulla?

Back 2

Cortex: dense
Medulla: pale

Front 3

Rectum above pectinate line drains to what nodes?

Back 3

Internal iliac nodes

Front 4

Anal canal below pectinate line drains to what nodes?

Back 4

Superficial inguinal nodes

Front 5

Stimulus for development of helper T cell into either Th1 or Th2?

Back 5

IL-12 --> Th1
IL-4 --> Th2

Front 6

HLA DR 7 association?

Back 6

Steroid-responsive nephrotic syndrome

Front 7

HLA DR 5 associations?

Back 7

Pernicious anemia (B12 deficiency)
Hashimoto's thyroiditis

Front 8

HLA DR 4 associations?

Back 8

Rheumatoid arthritis and DM type 1

Front 9

Graves' disease HLA association?

Back 9

HLA B8

Front 10

Hemochromatosis HLA association?

Back 10

HLA A3

Front 11

HLA DR2 associations?

Back 11

MS, hay fever, SLE, Goodpasture's

Front 12

Antigen loading location for MHC I?

Back 12

RER

Front 13

Antigen loading location for MHC II?

Back 13

Loaded following release of invariant chain in an acidified endosome

Front 14

Function of beta-2 microglobulin?

Back 14

Aids in transport of MHC I and antigen to cell surface
- can also form amyloid

Front 15

Cytokines that enhance natural killer cell activity?

Back 15

IL-12, IFN-beta, IFN-alpha

Front 16

Macrophage-lymphocyte interaction?

Back 16

Activated lymphocytes release IFN-gamma
Activated macs release IL-1, TNF-alpha
--> stimulate each other

Front 17

Inhibition of Th1 and Th2 cells?

Back 17

Th1: inhibited by IL-10 from Th2 cells

Th2: inhibited by IFN-gamma from Th1 cells

Front 18

Perforin vs granzyme?

Back 18

Granzyme: serine protease, activates apoptosis inside target cell
Perforin: helps deliver content of granules into target cell
- both released from cytotoxic T cells

Front 19

What is granulysin?

Back 19

Antimicrobial, induces apoptosis

- released from cytotoxic T cells

Front 20

4 methods of generating Ab diversity?

Back 20

1. Random VJ/VDJ recombination
2. Random heavy + light chain combos
3. Somatic hypermutation
4. Addition of nucleotides during recombination (terminal deoxynucleotidyl transferase)

Front 21

APC - CD4 interactions?

Back 21

MHC II - CD4 (with TCR)
B7 - CD28 (costimulation)

Front 22

Th2 - B cell interaction?

Back 22

CD40L (Th cell) - CD40R (B cell)
Th2 releases IL 4, 5, 6, 10

Front 23

Virus infected cell, Th1, and CD8 T cell interaction?

Back 23

MHC I (virus infected) - CD8/TCR (CD8 T cell)
Costimulation: IL 2 (Th1) - IL 2 R (CD8)

Front 24

T cell location in spleen?

Back 24

Periarterial lymphatic sheath (PALS) and white pulp

Front 25

B cell location in spleen?

Back 25

Follicles in white pulp of spleen

Front 26

Blood smear findings post-splenectomy?

Back 26

- Howell-Jolly bodies (nuclear remnants in RBCs)
- Target cells
- Thrombocytosis

Front 27

2 factors that are decreased with splenic dysfunction?

Back 27

1. Decreased IgM (--> decreased complement activation/opsonization of encapsulated organisms)
2. Decreased tuftsin (normally increases ability of macrophages to phagocytose)

Front 28

Location of APCs in spleen?

Back 28

Marginal zone (outer edge)

Front 29

3 diseases that involve increased follicle size in lymph nodes?

Back 29

HIV, RA, SLE

Front 30

Medullary cords vs sinuses?

Back 30

Cords: closely packed lymphocytes and plasma cells

Sinuses: reticular cells and macrophages

Front 31

Area of lymph node enlarged in extreme cellular immune response?

Back 31

Paracortex (houses T cells)

Front 32

What happens to thymus-independent antigens?

Back 32

Can't be presented to T cells by MHC (because they lack peptide component)
--> stimulate release of IgM Abs only and do NOT result in immunologic memory

Front 33

What are thymus dependent antigens?

Back 33

Antigens that contain a protein component
--> Class switching and immunologic memory occur after B cell interaction with Th2 cells (CD40-40L and release of IL 4, 5, 6)

Front 34

What are patients with IL-12 deficiency at risk for?

Back 34

Decreased Th1 response --> disseminated mycobacterial infections
- decreased IFN-gamma levels

Front 35

Patients with chronic mucocutaneous candidiasis have deficient what?

Back 35

T cell dysfunction

Front 36

Features of Hyper-IgE syndrome (Job's syndrome)?

Back 36

"FATED":
coarse (leonine) Facies
cold (non-inflamed) staph Abscesses
retained primary Teeth
IgE
Derm problems (eczema)
+ red hair
^^ Due to failure of Th cells to produce IFN-gamma --> neutrophils can't respond to chemotactic stimuli

Front 37

Defective CD40L on helper T cells causes what condition?

Back 37

Hyper IgM syndrome
- inability to class switch
- severe pyogenic infections early in life

Front 38

Sinus, lung infections, milk allergies, diarrhea, anaphylaxis when exposed to IgA, frequent SP/giardia infections. Disease?

Back 38

Selective Ig deficiency
- IgA deficiency most common --> failure to mature into plasma cells
- decreased secretory IgA

Front 39

Cause and risks of CVID?

Back 39

Caused by defect in B-cell maturation.

Increased risk of autoimmune disease (ITP, AIHA), lymphoma/malignancy, sinopulmonary infections, pneumonia, GI, etc

Front 40

Lab findings in CVID?

Back 40

Normal number of B cells
Decreased plasma cells and immunoglobulin

Front 41

Differentiation of Bruton's agammaglobulinemia vs CVID?

Back 41

CVID: normal # B cells

Bruton's: decreased number of B cells (normal pro-B)

Front 42

Cause and presentation of Bruton's agammaglobulinemia?

Back 42

Cause: X-linked recessive defect in BTK (tyrosine kinase) --> blocks pre-B to mature B cell maturation

Present with recurrent bacterial infections after 6 months (decreased maternal IgG) due to opsonization defect

Front 43

2 factors that prevent complement activation on self cells?

Back 43

Decay accelerating factor (DAF) and C1 esterase inhibitor

Front 44

Effect of C3a and C5a?

Back 44

Anaphylaxis

(C5a: also neutrophil chemotaxis)

Front 45

Deficiency of C3 causes what?

Back 45

Severe, recurrent pyogenic sinus and respiratory tract infections
Increased susceptibility to type III hypersensitivity reactions

Front 46

Complement factors involved in alternative pathway?

Back 46

C3, B, D

Front 47

Complement factors involved in classic pathway?

Back 47

C1, C2, C4, C3

Front 48

Passive immunity is available for how long and after what exposures?

Back 48

Half life of Abs ~ 3 weeks

After exposure to:
Tetanus toxin, Botulinum toxin, HBV, Rabies

Front 49

Bacteria with antigenic variation?

Back 49

Salmonella (flagella variants)
Borrelia (relapsing fever)
Neisseria gonorrhoeae (pilus prot)

Front 50

Bacterial superantigens link what to what?

Back 50

Cross-link beta region of TCR to MHC Class II on APCs
--> uncoordinated release of IFN-gamma from Th1 cells --> release of IL-1, IL-6, and TNF-alpha from macs

Front 51

Molecular pathway of endotoxin/lipopolysaccharide?

Back 51

Directly stimulate macrophages by binding to endotoxin receptor CD14 (no Th cell involvement)

Front 52

Cell surface proteins on B cells?

Back 52

Ig, CD19, CD20, CD21, CD40, MHC II, B7

Front 53

Cell surface proteins on T cells?

Back 53

TCR, CD3, CD28
- CD4, CD40L
- CD8

Front 54

Cell surface proteins on macrophages?

Back 54

MHC II, B7, CD40, CD14, receptors for Fc and C3b

Front 55

Cell surface proteins on NK cells?

Back 55

Receptors for MHC I, CD16 (binds Fc), CD56 (unique for NK cells)

Front 56

Alpha and beta vs gamma interferon?

Back 56

Alpha and beta: inhibit viral protein synthesis

Gamma: increase MHC I and II expression and antigen presentation in all cells

Front 57

IL-12?

Back 57

Secreted by macrophages and B cells.

Induces differentiation of T cells into Th1 cells and activates NK cells.

Front 58

Actions of TNF-alpha?

Back 58

Mediates septic shock. Activates endothelium. Causes leukocyte recruitment and vascular leak.

Front 59

Idiopathic thrombocytopenia purpura (ITP) hypersensitivity type?

Back 59

Type II hypersensitivity

Front 60

Polyarteritis nodosa hypersensitivity?

Back 60

Type III hypersensitivity

Front 61

Hypersensitivity pneumonitis type?

Back 61

Type III hypersensitivity

Front 62

Graft vs host hypersensitivity type?

Back 62

Type IV hypersensitivity

Front 63

Hashimoto's hypersensitivity type?

Back 63

Type IV hypersensitivity

Front 64

Guillain-Barre hypersensitivity type?

Back 64

Type IV hypersensitivity

Front 65

Type 1 DM hypersensitivity type?

Back 65

Type IV hypersensitivity

Front 66

Multiple sclerosis hypersensitivity type?

Back 66

Type IV hypersensitivity

Front 67

Ab in mixed connective tissue disease?

Back 67

Anti-U1 RNP (ribonucleoprotein)

Front 68

Anti-desmoglein Ab?

Back 68

Pemphigus vulgaris

Front 69

Abs in Hashimoto's?

Back 69

Antimicrosomal, Antithyroglobulin

Front 70

Ab in polymyositis, dermatomyositis?

Back 70

Anti-Jo-1

Front 71

IL-2 receptor antibody and use?

Back 71

Daclizumab
- used to prevent acute rejection of renal transplant

Front 72

Rituximab mechanism and use?

Back 72

Anti-CD20
- B cell Hodgkin's lymphoma

Front 73

Anti-CD3 antibody and use?

Back 73

Muromonab-CD3 (OKT3)
- prevent acute transplant rejection

Front 74

Uses of alpha interferon?

Back 74

Hepatitis B, C
Kaposi's sarcoma
Leukemias
Malignant melanoma

Front 75

2 drugs for treatment of thrombocytopenia?

Back 75

Oprelvekin (IL-11) and Thrombopoietin

Front 76

2 drugs for recovery of bone marrow?

Back 76

Filgrastim (G-CSF)
Sargramostim (GM-CSF)

Front 77

IL-2 recombinant cytokine and use?

Back 77

Aldesleukin
- used for renal cell carcinoma and metastatic melanoma

Front 78

Sirolimus (rapamycin) mechanism and AEs?

Back 78

Inhibit mTOR --> inhibit T cell proliferation in response to IL-2

AEs: hyperlipidemia, thrombocytopenia, leukopenia

Front 79

Antimetabolite precursor of 6-mercaptopurine?

Back 79

Azathioprine

Front 80

What do cyclosporine and tacrolimus (FK506) each bind to?

Back 80

Cyclosporine: bind cyclophilins
Tacrolimus: bind FK-binding protein

Both inhibit release of IL-2 and cytokines

Front 81

Toxicity of cyclosporine?

Back 81

Predispose patients to viral infections and lymphoma
- nephrotoxic (preventable with mannitol diuresis)
- hirsutism

Front 82

Toxicity of tacrolimus?

Back 82

Nephrotoxicity
Peripheral neuropathy
HTN
Pleural effusion
Hyperglycemia
Hair loss

Front 83

Role of IL-10?

Back 83

Modulate inflammatory response. Inhibit actions of activated T cells and Th1. Activate Th2.

Secreted by Th2 cells and regulatory T cells.

Front 84

Cause of and findings in Leukocyte adhesion deficiency (type 1)?

Back 84

Defect in LFA-1 integrin (CD18) protein on phagocytes

Get recurrent bacterial infections, absent pus formation, delayed separation of umbilicus.

Front 85

Recurrent pyogenic infections (staph, strep), partial albinism, peripheral neuropathy. Disease?

Back 85

Chediak-Higashi syndrome.

Defect in microtubular function with decreased phagocytosis.

Front 86

Thrombocytopenic purpura, Infections, Eczema. Disease and cause?

Back 86

Wiskott-Aldrich syndrome.

Progressive deletion of B and T cells. X linked recessive defect.

Front 87

Triad in ataxia-telangiectasia?

Back 87

Cerebellar defects (ataxia)
Spider angiomas (telangiectasias)
IgA deficiency

Front 88

Lab values in Wiskott-Aldrich syndrome?

Back 88

High IgE, IgA
Low IgM
Normal IgG

Progressive deletion of B and T cells. X linked recessive defect.