Respiratory Systems 12 - Lung immunology Flashcards
Define hypersensitivity
An exaggerated response - can be immunological (allergy) or non immunological (eg. lactose intolerance or inability to take certain medications)
Define allergy
- An exaggerated immunological response to a foreign substance which is inhaled, swallowed, injected, or comes in contact with the skin or eye
- Allergy is a mechanism
When are T helper type 1 cells used?
- Viruses
- Bacteria
- Fungi
- Protozoa
When are T helper type 2 cells used?
- Helminths (worms)
- Ectoparasites (ticks)
Which cells and antibodies are Th1?
- Th17 cells
- NK cells
- Cytotoxic T cells
- IgM, IgA, IgG
Which cells and antibodies are Th2?
- IgE and IgG1
- Epithelial barriers
- Lymphoid cells
- Eoisinophils, mast cells, basophils, activated macrophages
Describe the pathophysiology of seasonal allergic rhinitis
- Involves eosinophils and Th2 cells
- Involves IgE, produced by plasma cells
Define atopy
The hereditary predisposition to produce IgE antibodies against common environmental allergens
Give examples of atopic diseases
- Allergic rhinitis
- Asthma
- Atopic eczema
How are allergic tissue reactions in atopic subjects characterised?
Infiltration of Th2 cells and eosinophils
Define the allergic march
The common progression of atopic diseases from atopic dermatitis to allergic asthma
What proportion of the population are affected by rhino-conjunctivitis?
- Up to 25% (12-15% children and 11-17% adults)
- The UK prevalence is the highest in europe
List the common causes of perennial allergic rhinitis and asthma
- House dust mite
- Cats
- Dogs
- Alternaria
- Horses
- Cockroach
List the phenotypes of asthma based on control/severity
- Intermittent, mild with allergy frequently important
- Persistant, manageable, allergy often important
- Chronic severe, uncontrolled by treatment
List the phenotypes of asthma based on endotype (defined by pathophysiological mechanisms)
- Allergic, atopic or eosinopilic asthma
- Neutrophilic asthma
- Exercise induced asthma
What percentage of the population are affected by extrinsic allergic alveolitis?
0.1%
Describe the mechanism of extrinsic allergic alveoloitis
- Small allergic particles penetrate to the distal airways and the alveoli
- Antibody/antigen complexes form outside of the alveoli, in the surrounding tissue fluid, activating complement system, neutrophils, and macrophages
List some examples of extrinsic allergic alveolitis
- Farmers lung (hay)
- Bird fanciers lung
- Air conditioner lung
- Mushroom workers lung
- Malt workers lung
- Coffee workers lung
- Millers lung (flour)
- Hot tub lung (bacterial contaminations)
List the principles of treatment of allergic diseases
- Allergen avoidance
- Anti-allergic medication
- Immunotherapy (desensitisation)
List the effects of seasonal allergic rhinitis
- Work productivity reduces
- School performance reduces
- Sleep deprivation
Which country has the highest prevalence of allergic rhinitis, and which has the lowest in europe?
- Italy has the lowest
- Belgium has the highest
What percentage of the global population are affected by allergic rhinitis?
40%
List the treatments available for allergic rhinitis
- Antihistamine
- Allergen avoidance
- Nasal steriod
- Immunotherapy (subcutaneous injections or tablets)
List the advantages and disadvantages of allergen injection immunotherapy.
Advantages
- Effective, long lasting immunity
Disadantages
- Severe allergic reaction
- Time consuming
- Standardisation problems
How does immunotherapy work in allergy?
- Production of induced and natural T regulatory cells
- B regulatory cell production (suppresses T cell differentiation and increases Treg cell proliferation)
- IgG produced rather than IgE
Define intolerance
The inability to eat a food or take a drug without adverse effects
