Hypersensitivity and Autoimmunity Flashcards
What is type I hypersensitivity also know as?
Allergy
How does type I hypersensitivity principally arise?
Through the inappropriate synthesis of IgE
Define Atopy
A state of sub-clinical immune sensitisation
What can the environmental antigens linked with type I hypersensitivity be?
Airborne
Ingested
Injected
Through skin contact
What is allergy the end result of?
Complex interplay of a number of factors
Which antibodies mediate type II hypersensitivity?
IgG or IgMs
What 2 types of antigen are involved in type II hypersensitivity?
External
Self-derived
What are the 4 mechanisms of tissue damage in type II hypersensitivity?
Complement of activation
Fc binding of immunoglobulin
Antibody dependent cellular cytotoxicity
Effects on target cell function
How do the clinical conditions arise in type III hypersensitivity?
Abnormal deposition of formed antigen
Which type of hypersensitivity is not mediated by antibodies?
Type IV
What is type IV hypersensitivity mediated by?
Th1 cells
The response in type IV hypersensitivity is due to what?
Contact with inert environmental substances
What causes tissue damage in hypersensitivity?
Exaggerated immune response
What is the low molecular weight agent in type IV hypersensitivity termed?
Hapten
What is the host protein in type IV hypersensitivity called?
Carrier
What delay is there between the antigen exposure and the resonse in type IV hypersensitivity?
48-72 hours
What is serum sickness? (Hypersensitivity)
A systemic illness where immune complexes are deposited throughout many tissues
What is an arthus reaction? (Hypersensitivity)
Localised disorder where complexes form locally in the tissues
What is an autoimmune disease?
Immune responses of an organism against its own cells and tissues
What is the name given to the process by which the immune system avoids producing damaging reactions against autoantigens?
Tolerance
What immunity is tolerance a feature of?
Adaptive
What are the four main factors for autoimmuntiy aetiology?
Genetic factors
Immune Regulatory factors
Hormonal factors
Environmental factors
Autoimmunity pathogenesis arises due to interaction of the aetiological factors in association with what?
Immune effector mechanisms
In which type of hypersensitivity are immune complexes formed?
Type III hypersensitivity
What is a HLA?
Human leukocyte antigen
What type of disorders arise as organ-specific disorders?
Autoimmune endocrine disorders
What type of disorders arise as non-organ specific disorders?
Connective tissue disorders
What is an organ specific autoimmune disorder?
An autoimmune disorder in which specific organs are attacked by the immune system
