Lung Immunology Flashcards
What are the 3 types of allergic diseases?
Upper airways = allergic rhinitis
Bronchi = asthma
Alveoli = allergic alveolitis
What are the 2 types of hypersensitivities and how are these split even further?
Immunological = IgE mediated (atopic disease) e.g. asthma or Non IgE mediated e.g. farmers lung
Non-immunological = Intolerance e.g. food, enzyme deficiency e.g. lacrosse, pharmacological e.g. hypersensitivity to aspirin
What is allergy?
Exaggerated response tho allergen
NOT A DISEASE, it is a mechanism
What do t helper type 1 and 2 target respectively?
Type1 (stimulate cytotoxic, IgM, IgA)= viruses, bacteria, fungi, Protozoa Type 2 (stimulate eosinophils, basophils, mast cells IgE)= helminth parasites and ectoparasites (ticks)
What is the pathway for acute allergy?
IgE made by B cells helped by Th2
IgE binds to mast cell (in tissues)
Allergen binds to IgE
Mast cell degranulation and produces histamine
What is the pathway for chronic allergy?
Antigen presenting cell binds to allergen
Th2 detects it and clones to for cytokines and chemokine
What are the 4 cytokines that Th2 cells produce?
Il-4 = IgE synthesis
Il-5 = eosinophils development
Il-9 = mast cell development
Il- 13 = IgE synthesis and airway hyperesponsivness
What is atopy?
Predisposition to produce IgE against common allergens
These tissues are normally full of Th2 and eosinophils
What is the atopic march?
Allergic disease progressing during life starting with food allergies and ending with asthma
BUT on an individual level this is not very common
What is rhinitis?
Allergic disease of the upper airway
Affects 15% children and adults
Different allergens that peak at different times of year but mainly spring and summer
What does it mean when asthma is a heterogenous disease?
It has many phenotypes
- different severities
- induced by different things
- different mechanisms e.g. eosinophils and neutrophils
What is the mechanism of allergic alveolitis?
Small particles penetrate alveolus
Come into contact with antigens in the capillary
Trigger other responses
What is anaphylaxis?
Systemic allergic reaction
- tongue swelling
- bronchoconstriction
- tingling
What is the trend of allergic disease?
They are increasing
no. Of hospital admissions due to anaphylaxis increase x7 from 1990 to 2000
What is the hygiene hypothesis?
Getting rid of germs, means that our bodies become more allergic to germs when they do come into contact with them