14 Lung Immunology and Allergic Disease Airway Flashcards
Q: Disease of upper airways? of bronchi? of alveoli?
A: Allergic rhinitis
asthma
allergic alveolitis
Q: What is hypersensitivity? 2 types?
A: exaggerated response
- immunological - “allergies”
- non immunological (no immune mechanism)
Q: 2 types of immunological hypersensitivity? 4 examples.
A: Non-IgE-mediated allergic diseases
(e.g. Farmers lung)
IgE-mediated = atopic diseases
- hayfever
- eczema
- asthma
Q: 3 types of non-immunological hypersensitivity? Example for each.
A: Intolerance (e.g.food)
Enzyme deficiency (e.g.lactase DH def)
Pharmacological e.g. Aspirin hypersensitivity
=> don’t have immune mechanism
Q: What is allergy?
A: Allergy is an exaggerated (inappropriate) immunological response to a foreign substance (allergen) which is either inhaled, swallowed, injected, or comes in contact with the skin or eye
hypersensitivity
Q: Allergy. Mechanism or disease?
A: Allergy is a mechanism (not a disease)
Allergic mechanisms play an important role in some diseases all the time, and in others for some of the time
Q: How can adaptive immunity generally be split? How is allergy referred to? What molecule does it revolve around?
A: Th1 and Th2
Th2 gone wrong / uneducated Th2 immunity
IgE
Q: Th1 mediated responses are launched against which 4 pathogens? Which cells are involved? (3) Which Ig? (3)
A: Viruses, bacteria, fungi, protozoa
Th17 cells, NK cells, cytotoxic T cells
IgM, IgA and IgG antibody subclasses
Q: Th2 mediated responses are launched against which 2 pathogens? Which cells are involved? (5) Which Ig? (2)
A: helminths (“worms”), ectoparasites (“ticks”) = multicellular
innate lymphoid cells, eosinophils, mast cells, basophils, activated macrophages
IgE and IgG1 antibodies epithelial barriers,
Q: What are the 2 phases of an allergic reaction? Describe each pathway.
A: acute and chronic phases of allergic reaction
- Allergen -> IgE antibody coating mast cell -> mast cell degranulation (and histamine produced) -> acute symptoms of allergy
- Same allergen -> APC -> Th2 cytokines and chemokines -> chronic symptoms of allergy
Q: How does an allergen produce acute symptoms of allergy? (7) How long do these symptoms last?
A: 1. if you’re allergic: identifies correctly as foreign but inappropriate response -> results in IgE production through help of Th2
- IgE will go in blood-> bind to granulocytes -> mast cells (in tissues- gut, lung, muscousal surfaces, skin) -> stay bound for long time)
MAST CELLS= EARLY PHASE
- and basophils (in periphery in blood)
- body will continue to make IgE antibody
- next time that specific antigen is encountered-> allergen will crosslink IgE on surface of mast cells
- -> mast cell undergoes immediate enzymatic reactions -> degranulate
- substance of granules made= responsible for acute symptoms of allergy that last minutes/hours (molecules locally effect eg by causing inflammation eg histamines)
Q: How does IgE bind to mast cells? How long do they stay bound?
A: IgE will bind to mast cells via receptor: high affinity receptor for IgE= FC epsilon R1 (FCER1) -> stay there for months (very long lasting)
Q: What happens the second time you encounter allergens? (3) Called? How long does it take?
A: 1. allergen coming 2nd time will also bind to other receptors and do other things
- APC activates Th2 cells -> replicates -> produces Th2 cytokines and chemokines
- -> Chronic symptoms of allergy (takes hours, days) = late allergic reaction
T CELL= LATE PHASE
Q: What do Th2 cells produce? (4) What do they each do? Which 2 are related to asthma?
A: IL-4 -> IgE synthesis (class switching of B cells to make IgE)
IL-5 -> Eosinophil development (can be a target for asthmatics)
IL-9 -> Mast cell development
IL-13 -> IgE synthesis + Airway Hyperresponsiveness + airway remodelling in asthma
Q: What does atopy mean? What is it? Name 3 atopic diseases.
A: Atopy means out of place (something inappropriate)
Atopy is the hereditary predisposition to produce IgE
antibodies against common environmental allergens