lung infection and immunity

Question 1

locations of allergic airway diseases (allergic rhinitis, asthma, allergic alveolitis)

Answer 1

upper airways (allergic rhinitis), bronchi (asthma), aveoli (allergic alveolitis)

Question 2

define hypersensitivity

Answer 2

exaggerated response to foreign substance (immunological or not)

Question 3

immunological exaggerated response

Answer 3

allergy - IgE-mediated (atopic diseases such as hayfever), non-IgE-mediated allergic diseases

Question 4

non-immunological exaggerated response

Answer 4

intolerance, enzyme deficiency, pharmacological

Question 5

define allergy

Answer 5

exaggerated immunological response to allergen (inhaled, swallowed, injected, comes in contact with skin/eye); mechanism, not disease; important role in some diseases all or some of the time

Question 6

allergy: early and late response (cells and signs)

Answer 6

early: mast cells, basophils causing watery eyes, itchy nose etc.; late: eosinophils, T cells causing nasal congestion

Question 7

aetiology of seasonal allergic rhinitis

Answer 7

sensitisation → 2nd (chronic) exposure after several seasons → allergic response; if allergic nasal epithelium disrupted, innate then adaptive response

Question 8

allergy: 3 cytokines and major cell

Answer 8

IL-4, -5, -13; eosinophils

Question 9

define atopy

Answer 9

hereditary predisposition to produce IgE antibodies vs common environmental allergens

Question 10

what are the 3 atopic diseases

Answer 10

allergic rhinitis, asthma, atopic eczema

Question 11

what are allergic tissue reactions in atopic subjects characterised by

Answer 11

infiltration of Th2 cells (IL-9) and eosinophils

Question 12

what causes allergic rhinitis

Answer 12

can be seasonsal; commonly caused by many animals (pets, cockroaches) and pollen

Question 13

features of asthma

Answer 13

very heterogeneous; based on control, severity or endotype/endo-phenotype

Question 14

asthma severity scale

Answer 14

intermittent, persistant, chronic

Question 15

endotypes of asthma

Answer 15

allergic, atopic or eosinophilic; neutrophilic; exercise-induced

Question 16

extrinsic allergic alveolitis mechanisms

Answer 16

small allergens penetrate to distal airways and enter alveoli → formation of antigen/antibody complexes → complement, neutrophils, macrophages, fibroblasts triggered and lymphocytes recruited

Question 17

3 principles of treatment of allergic disease

Answer 17

allergen avoidance, anti-allergic medication (e.g. anti-histamines, corticosteroids), immunotherapy (allergen-specific immunotherapy)

Question 18

advantages of allergen-injection immunotherapy

Answer 18

effective, long-lasting immunity

Question 19

disadvantages of allergen-injection immunotherapy

Answer 19

occasional severe allergic reaction, time consuming, standardisation problems

Question 20

features of allergen immunotherapy

Answer 20

modulate dendritic cells, deviation (Th2 to Th1 cells, Th cells to Treg that inhibit TfE cells), induction of regulatory responses and IgG to prevent IgE from cross-linking basophils and mast cells to produce an allergic reaction, desentising to allergens

Question 21

allergic rhinitis mechanism

Answer 21

allergens pass over epithelium and captured by dendritic cells → migrate to lymph nodes → stimular Th cells to differetiate to Tfh (IL-4) and Th2 (IL-9) → activate B cell and mast cell respectively → allergen specific IgE antibodies released → bind to mast cell FcE receptors → allergen cross links IgE antibodies, degranulation occurs → histamine release

Question 22

epidemiology of allergic rhinitis

Answer 22

affects up to 25% of the population

Question 23

epidemiology of asthma

Answer 23

affects up to 10% of the population