14 Lung Immunology

Question 1

What are the categories of hypersensitivity

Answer 1

Immunological - IgE mediated (asthma, eczema and hay fever) and non-IgE mediated (farmer’s lung)
Non immunological - food intolerance, enzyme deficiency (lactase DH) and pharmacological (aspirin hypersensitivity)

Question 2

Define allergy

Answer 2

An exaggerated response to a foreign substance which is either inhaled, swallowed, infected or comes in contact with skin or eye

Question 3

True or False: allergy is a disease

Answer 3

False: it’s a mechanism that play a temporary or permanent role in a disease

Question 4

Define atopy

Answer 4

Hereditary predisposition to produce IgE antibodies against common environmental allergies

Question 5

List examples of atopic diseases

Answer 5

Allergic rhinitis
Asthma
Eczema

Question 6

Allergic tissue reactions in atopic subjects are characterised by what infiltration

Answer 6

Th2 lymphocytes and eosinophils

Question 7

How can acute and chronic symptoms of allergy be distinguished immunologically

Answer 7

Acute - involves IgE mediated response whereby mast cells coated by IgE elicits the release of histamine and occur within minutes and hours
Chronic - involves Th2 and antigen presenting cells whereby the symptoms present within hours and days

Question 8

CD4 Th 2 cells produce cytokines including IL-4, IL-5, IL-9 and IL-13. What are their effects

Answer 8

IL-4 IgE synthesis
IL-5 eosinophils development
IL-9 mast cell development
IL-13 IgE synthesis and airway hyperresponsiveness

Question 9

What is the term “allergic march”

Answer 9

Common progression from atopic dermatitis to allergic asthma

Question 10

Give an example of allergic rhinitis and list potential triggers

Answer 10

Rhino conjunctivitis (hay fever): prevalence of 17 million of the population
Triggers:
- allergic causes: grass, tree, weed pollens, house dust mite
- non allergic causes: infection, immunodeficiency, structural abnormalities

Question 11

What are the triggers for allergic asthma

Answer 11

Immunological: dust mite, pollen, cigarette smoke, pollution, pets, cold/flu, hormone, drug (aspirin)
Non-immunological: exercise, cold air, stress

Question 12

What are the percentage of patients with asthma are allergic (atopic) type and non-atopic asthmatics

Answer 12

Atopic: 75% and non-atopic; 25%

Question 13

What are the symptoms of asthma

Answer 13

Chest tightness
Breathlessness
Cough
Wheeziness

Question 14

How can asthma be categorised

Answer 14

Based on control/severity:
- intermittent (mild, allergy frequently important)
- persistent (manageable, allergy often important)
- chronic (severe and uncontrolled by treatment)
Endotype (based on pathophysiology)
- allergic, atopic or eosinophilic asthma
- neutrophilic asthma
- exercise induced asthma

Question 15

What is extrinsic allergic alveolitis

Answer 15

It is a non-IgE T cell mediated inflammatory disease affecting alveoli and interstitium
It is caused by repeated inhalation of certain antigens (usually bacterial or fungal microorganisms from workplace) in susceptible people

Question 16

What are the examples of extrinsic allergic alveolitis

Answer 16

Farmer’s lung - mouldy hay
Air conditioner’s lung - air conditioner mould
Hot tub lung - bacterial contamination
Coffee worker lung - unroasted coffee bean

Question 17

Name a host susceptibility factor to extrinsic allergic alveolitis

Answer 17

Polymorphism of TNFa promoter region

Question 18

What are the histological finding of a patient with extrinsic allergic alveolitis

Answer 18

CD 8 T cells
Foamy alveolar macrophages
Granuloma
Non specific interstitial pneumonia

Question 19

What is the management for EAA

Answer 19

Oxygen

Oral corticosteroids

Question 20

What are the symptoms of general anaphylaxis

Answer 20

Swollen lips and tongue
Arrhythmia 
Bronchoconstriction
Laryngeal oedema
Vomiting, diarrhoea and lain
Urticaria/hives
Tingling of hands and feet
Anxiety

Question 21

What are the causes of general anaphylaxis

Answer 21

Drug (penicillin)
Food (peanut, milk)
Insect sting
Latex

Question 22

What are the principles of treatment for allergic airway diseases

Answer 22

Allergen avoidance
Anti allergic medication - anti histamine (histamine 1 antagonist)
Topical corticosteroids
Immunotherapy

Question 23

Explain the basis of immunotherapy against allergic airway disease

Answer 23

Administration of increasing concentrations of allergenic extracts of a long period of time

Advantages: effective and produces long lasting effect

Disadvantages: risk of developing anaphylaxis, time consuming and standardisation problems

Attempt to down regulate Th2, upregulate Th1 and upregulate Treg (increase IL-10)

Question 24

What are the 5 categories in allergy

Answer 24

1. Asthma
2. Drug allergy
3. Food allergy
4. Skin allergy
5. Rhinitis