Flashcards in Hypersensitivity and autoimmunity Deck (21)
1
What are type I,II and II mediated by?
Antibodies
2
What is type 4 caused by?
Inappropriate Th1 cell action
3
What is type 1 sensitivity also known as?
Allergy
4
How does type 1 principally arise?
Inappropriate IgE synthesis
5
In type 1 what id the IgE directed towards?
Antigens that may be airborne, ingested, skin contact or injected
6
What do the allergic problem arise from?
Genetic factors
Environmental factors
Hormonal and neurological influences
Immune regulatory factors
7
Atopy
A state of sub-clinical immune sensitisation
8
What are type 1 allergic reaction mediators?
Histamine
Mucosal oedema
Vasodilation
9
What is type 2 hypersensitivity mediated by?
IgG or IgM antibodies directed against antigens found on the surface of cells or fixed within certain tissues
10
What can the antigens be?
Exogenous or derived from self
11
What happens in type 2?
Complement activation stimulate phagocyte
Inhibit function
12
How do clinical conditions in type 3 arise?
Abnormal deposition of formed antigen or antibody in tissues
13
Pathological immune complex inflammation
Deposited in many tissues - serum sickness
Complexes formed locally in tissues - arthus reaction
14
Why do type 4 reactions occur?
Immune system finds it difficult to destroy these environmental agents
15
What are type 4 mediated by?
Cytokines products eg interleukin-2 and interferon
Th1 cells
16
Hapten
Low molecular weight agent
17
Carrier
Host protein
18
How much of a delay is there in type 4?
48-72 hours
19
Tolerance
The process by which the immune system avoids producing damaging reactions against self antigens
20
Effector mechanisms in autoimmunity
T cell and B cell
Immune complex formation
Recruitement of innate compound
21