2. Immune System

Question 0

Type II hypersensitivity

Answer 0

[antibody-dependent cytotoxic]
[IgG or IgM] bind to receptors on host cell (autoimmune)&raquo_space; triggers complement - NK cells, macrophages

e.g. Graves, corneal graft rejection

Question 1

Type I hypersensitivity

Answer 1

[immediate type]

[prior exposure] B cell recog antigen&raquo_space; produ IgE
[2nd exposure] IgE binds to mast cells/basophils&raquo_space; allergen binds to IgE&raquo_space; mast cell degranulation - release histamines (vascular permeability, pruritis, smooth muscle spasms), cytokines, chemokines, proteases, neutrophils, eosinophils

e.g. Hay fever, Vernal conjunctivitis

Question 2

Type III hypersensitivity

Answer 2

[immune complex]
[IgG, maybe IgM] - Antigen-antibody complex&raquo_space; accumulate in tissues&raquo_space; activates complement

e.g. Lupus, Sjögren’s syndrome

Question 3

Type IV hypersensitivity

Answer 3

[Delayed-type, cell-mediated]
[1-3 days after exposure] - T cells’ cytotoxic rxn

e.g. Contact dermatitis, Allograft rejection

Question 4

Type V hypersensitivity

Answer 4

[Autoimmune]

Question 5

Antibodies

Answer 5

“GAMED”
Types: IgG, IgA, IgM, IgE, IgD

Light chain dictate specificity

Question 6

Allergy testing

Answer 6

Skin prick test (SPT)
Total serum IgE
Serum specific IgE (RAST)

Question 7

Urticaria

Answer 7

[Hives, Wheals]

Erythematous, circumscribed, pruritic, cutaneous lesions

Question 8

Angioedema

Answer 8

[deeper swelling]

Affects face, hands / Suffocation (e.g. peanut allergy)

Question 9

Atopy triad

Answer 9

Asthma, Allergic rhinitis, Atopic dermatitis [IgE-mediated hypersensitivity]

Question 10

Allergic rhinitis

Answer 10

[seasonal/perennial]

From allergens in air

Question 11

Atopic dermatitis

Answer 11

[allergic/infantile eczema, allergic dermatitis]
90% of cases develop prior to age 5

[on face, elbows, knees]

• Lichenification
• Xerosis
• Ichthyosis

[Patchy lesions]
w/ edema, erythema, excoriation, scaling, hyperpigmentation

• Atopic keratoconjunctivitis
• Keratoconus
• Cararact at young age

Question 12

Atopic keratoconjunctivitis

Answer 12

[assoc w/ atopic dermatitis]

Itching, burning, mucoid discharge, conj hyperemia, SPK

Question 13

Keratoconus

Answer 13

[assoc w/ atopic dermatitis]

Corneal thinning w/ ectasia

Question 16

Anaphylaxis

Answer 16

[Acute] severe systemic allergic rxn

Question 17

Pruritis

Answer 17

Itching

Question 18

Lichenification

Answer 18

Thickening, accentuation of skin markings

Question 19

Xerosis

Answer 19

Dryness

Question 20

Ichthyosis

Answer 20

Keratinization of skin

Question 21

Excoriation

Answer 21

Skin abrasions

Question 22

Ecstasia

Answer 22

Dilation, enlargement