When Thing Go Wrong with the Immune System pt. 2

Question 1

Gell and Coombs classification of hypersensitivies

Answer 1

Type I, II, III and IV. Types can overlap.

Question 2

Hypersens. types with relevance to allergic diseases

Answer 2

Type I and II

Question 3

Sensitization

Answer 3

First exposure that induces an often weak or transient immune response

Question 4

Type I

Answer 4

IgE mediated.

Question 5

IgE mediated hypersens.

Answer 5

Cross-linking of FcE receptor on mast cells by antigen-binding on IgE causes degranulation

Question 6

Type II

Answer 6

New epitopes on cell surfaces makes them target of antibody mediated immune attack

Question 7

Type III

Answer 7

Soluble self antigen causes formation of immune complexes

Question 8

Serum sickness

Answer 8

Systemic type III HS following intravenous adiminstration of antigen.

Question 9

Type IV

Answer 9

T cell (TH2, TH1, CTL) mediated self reactivity, causing inflammation or cell death.

Question 10

Immune development

Answer 10

Maturation of immune components, beginning short after conception and continuing after birth.

Question 11

Th1 status in utero

Answer 11

Repressed due to mother’s Th2 bias. Failure to correct after birth can give elevated risk of allergy and other diseases.

Question 12

Atopy

Answer 12

Tendency to manifect local hypersensitivities. Defined as tendency to produce IgE.

Question 13

Mast cell response

Answer 13

Release of enzymes and toxic mediaters such as tryptase, histamine and heparin.
Recruitment of cells by Il-4 or Il-5, TNFα etc.

Question 14

Allergic rhinitis and hay fever are examples of…

Answer 14

Local type I HS.

Question 15

Immediate type HS1

Answer 15

If sensitization already found place, the response to the antigen is immediate and followed by a late phase response.

Question 16

Early/late phase mediaters

Answer 16

Early phase mediaters are enzymes and toxic mediators, late phase mediators are cellular responders recruited by the mast cells.

Question 17

Hyposensitization

Answer 17

Injection of increasing doses of allergen could shift the antigen response to IgG instead of IgE. Can also induce Treg cells that inhibit Th2 response (IgE production)

Question 18

Delayed-type HS

Answer 18

Type IV HS