Hypersensitivity Flashcards
What is an allergen?
An allergen is an antigen that causes an allergic reaction
What is type 1 hypersensitivity reaction mediated by?
IgE
What can type 1 hypersensitivity also be known as?
Immediate hypersensitivity
What can hypersensitivity type 1 reaction lead to ?
Anaphylaxis
What cells do type 1 allergens bind to IgE antibodies on?
Mast cells
What are haptens?
Any small molecule that can be recognized by a specific antibody but cannot by elicit an immune response
How can a hapten stimulate an immune response?
Must be chemically linked to a protein molecule
Main roles of type 1 hypersensitivity?
-immune cell recruitment
-neurotransmitter
-vasodilator
-endothelial constrictor
What is atopy?
The genetic tendency to develop allergic diseases to allaergens
What are examples of cutaneous atopy?
Hay fever
Eczema
Asthma
What are different allergy tests?
-Skin prick and patch tests
-Blood test
-Food challenge
What are examples of anti-allergy drugs?
Anti-histamines
Hydrocortisone
Epinephrine
What are immunological treatments for allergies?
Hypo or de sensitisation (repeat injections of allergen)
IgE to IgG production
How do anti-histamines work?
Compete with histamine for receptors
When is epinephrine used?
Anaphylactic shock
What is an example of type II hypersensitivity?
Transfusion reactions
Autoimmune hemolytic anaemia
What is an example of type III hypersensitvity?
Arthus reaction
Oral erythema multiforme
What is the key difference within type IV hypersensitivity reaction?
It is T cell mediated ( no antibodies)
What is an example of a type IV hypersensitivity reaction?
Contact dermatitis
Oral facial granulomatous (OFG)
What is type 2 and 3 hypersensitivity meidated by?
IgG or IgM
