Autoimmunity and Allergies Flashcards
(26 cards)
What are autoimmunity and allergy classified as?
Both are hypersensitivity diseases
What are the four types of hypersensitivity reaction?
- Type I Immediate
- Type II Antibody mediated
- Type III Immune complex mediated
- Type IV T cell mediated
What defines autoimmune disease?
A specific immune attack against one cell type or molecule
What are the two categories of autoimmune disease?
- Organ specific
- Systemic
Why does autoimmunity occur?
Due to the diversity of antigen receptors generated by random V(D)J recombination
What is central tolerance?
The deletion or editing of highly self reactive lymphocytes during development
What is peripheral tolerance?
Mechanisms to control autoreactive cells in the body
What mechanisms control autoreactive cells in the body?
- Regulatory T cells
- Anergy
- Immune checkpoints
What is the major genetic risk factor for autoimmunity?
HLA genes
How does class I HLA alleles relate to autoimmunity?
CD8 T cell driven diseases
How does class II HLA alleles relate to autoimmunity?
CD4 T cell driven diseases with autoantibodies
What are four environmental triggers of autoimmunity?
- Infection and molecular mimicry
- Microbiota disturbance
- Being a female
- Tissue damage and cytokine storms
What is molecular mimicry?
Immune response to a microbe triggers cross reaction to a structurally similar self protein
What is an example of organ specific autoimmune disease?
Type 1 diabetes
What immune cells are involved in type 1 diabetes and what are its possible trigger?
Possible viral trigger and CD4 and CD8 T cells involved
What is an example of systemic autoimmune disease?
Systemic Lupus Erythematosus
(SLE)
What occurs during Systemic Lupus Erythematosus?
Loss of tolerance to nuclear antigens
In what three ways can autoantibodies cause disease?
- Block receptors
- Stimulate receptors
- Immune complex deposition
What are three ways autoimmune diseases can be treated?
- Replace function
- Immunosuppression
- Monoclonal antibody biologics
What is an allergy?
A type I hypersensitivity reaction to usually harmless environmental antigens
What is atopy?
A genetic predisposition to develop allergic diseases
What are the five major players in allergy?
- Th2 cytokines (IL-4, IL-5, IL-13)
- IgE antibodies
- Mast cells
- Basophils
- Eosinophils
What are the five steps in immediate hypersensitivity response?
- First antigen exposure
- Th2 differentiation
- B cell class switching to IgE
- IgE binds FcεRI on mast cells
- Repeat exposure resulting in mast cell activation
What are two things that causes allergic predisposition?
- Genetics
- Environment
