D4.1 Asthma

Question 1

Describe structure of Respiratory tract epithelium

- describe function

Answer 1

Pseudo-stratified columnar epithelium with goblet cells.

- particles trapped on mucus fluid removed by coordinated cilia action

Question 2

What is the variable impermeable barrier to fluid formed by

• name function
• which cells can gain access

Answer 2

Claudin & occludin proteins - join the cytoskeleton of
adjacent cells
- prevents water loss & blocks entry of infectious and allergenic agents
- Increased permeability of asthmatic epithelial cells
- fluid lost from cells/ pathogens/ inflammatory cells can gain access

Question 3

functional cells of asthma

Answer 3

IgE and mast cells, basophils and eosinophils

Question 4

Asthma is usually what type of response

- cells involved lead to

Answer 4

ALLERGIC Th2 mediated response

- Mast cells produce products to result in lung smooth muscle contraction

Question 5

What jobs linked to asthma

Answer 5

Smokers who are

• prawn processors
• salmon processors

Question 6

Immunological Therapies for asthma

Answer 6

• Anti-IgE: Omalizumab
• Anti-CD4: Supressing Th2 response can make you more susceptible to infection - severe infections only
• Anti-IL-5
• Anti-TNF: can block tissue remodelling

Question 7

Name Th2 cytokines involves & consequences

Answer 7

Th2 cytokines
- IL-5: Eosinophilia
- IL-4 and IL-13: Goblet cell metaplasia,
Bronchial hyperreactivity (BHR)

Question 8

Describe Role of Epithelial cells

Answer 8

• TLR, NOD: Induces production of cytokines
• IL-25 (IL-17E): Amplifies Th2 cytokine production and eosinophilia
• IL-33 (IL-1 family member): Synergizes with SCF and IgER to activate mast cells, basophils and eosinophils & enhance their survival
• TSLP: Activates DC & promote Th2
• IL-22: Induces EC proliferation and production of anti-microbial peptides, Protects against extracellular bacteria

Question 9

Name some remodelling due to COPD

Answer 9

Destruction of alvelous
Mucus hypersecretion exudate (chronic bronchitis)
Narrowed bronchioles
Mucosal inflammation & fibrosis (chronic obstructive bronchiolitis)
Disrupted alveolar attachments (emphysema)

Question 10

Describe chronic lung injury

Answer 10

repeat episodes of inflammation 
continued tissue repair 
- distorted matrix deposition 
- mesenchymal cell prolifn 
- altered lung architecture

Question 11

Describe process of COPD damage

Answer 11

Multiple microscopic foci of injury occurring over many years >
Focal fibroblast proliferation (fibroblast foci) >
Collagen deposition > Progressive clinical course >
Death

Question 12

Activation of Th17 cells leads to:

Answer 12

Epithelial cells produce 
1. Defensins 
2. Inflammatory cytokines: (TNF, IL-1, IL-6)
This leads to:
Recruitment of neutrophils & macrophages
Alteration in mucus production
Epithelial cell denudation
Fibroblast proliferation
Collagen deposition
Change in architecture of lung and function

Question 13

Asthma vs COPD

Answer 13

COPD
- airways have become narrowed permanently (irreversible change to tissue)
- inhaled medication has limited benefit
Asthma
- narrowing of airways comes and goes, when exposed to a trigger
- dust, pollen or tobacco smoke.
- Inhaled bronchodilators open airways fully
Both treated with corticosteroids (COPD if caught early enough)
- Dampening down dysregulate immune response