Flashcards in Hypersensitivity and Autoimmunity Deck (34)
What is type 1 hypersensitivity?
- When the body recognises an environmental antigen as a pathogen
What does type 1 hypersensitivity release?
What cells are triggered by type 1 hypersensitivity?
- Mast cells
- Blood basophils
What happens during sensitisation?
- The allergen is shown to a T helper cell by an APC
- B cells then differentiate
What do B cells produce during sensitisation?
What occurs if the patient is exposed to the antigen after sensitisation?
- Mast cells release cytokines
- Allergic reaction results
What is type 2 hypersensitivity?
Body's antibodies bind to antigens on its own cells
What can happen if penicillin binds to blood cell?
Antibodies are produced in response to the antigens on that cells surface
What can IgG and IgM antibodies trigger?
What does the activation of the complement system cause?
What is type 3 hypersensitivity?
When the body forms immune complexes
What are immune complexes?
When antibodies stick together in a clump
With regards to concentration, how do immune complexes form?
- Low conc. of antibody
- High conc. of antigen
What causes type 4 hypersensitivity?
CD4 helper T cells recognise a foreign antigen
What do these CD4 helper T cells release?
What does the release of these cytokines cause?
How fast does the early phase response react?
What is released during the early phase response?
- Chemotactic factors
What cell releases the chemicals in the early phase response?
Mast cell mediators
What is released during the late phase response?
What cytokines are released in the late phase response?
What cells are the mediators of the late phase response?
What 2 complexes can form during type 3 hypersensitivity?
What is localised type 3 complexes and how is it cleared?
- Inflammation of nearby tissue
- Cleared by macrophages
What is an autoimmune disease?
Disorder caused by organ damage of the immune system targeting self antigens
What 5 factors can result in an autoimmune disease?
- Genetic factors
- Immune regulatory factors
- Hormonal factors
- Environmental factors
What are the pathogenic mechanisms of autoimmune disease?
- Cell mediated
- Antibody mediated
- Antibody + compliment
- Immune complex mediated
- Accumulation of innate compounds
Name 3 autoimmune thyroid diseases
- Hashimoto's thyroiditis
- Primary myxoedema
Name an autoimmune stomach disease