Allergies

Question 1

What are autoimmune disorders?

Answer 1

Where the immune system attacks our own bodies.

Question 2

What causes allergies?

Answer 2

Overproduction of IgE antibodies in response to harmless environmental antigens.

Question 3

Give some examples of allergies.

Answer 3

• Asthma
• Hay fever
• Allergic rhinitis
• Hives
• Dermatitis
• Food allergy
• Drug allergy

Question 4

What is an allergy?

Answer 4

Exaggerated immune response to a foreign antigen.

Question 5

What is atopy?

Answer 5

State that leads to an exaggerated IgE-mediated immune response.

Question 6

Atopic disorders are what type of disorders?

Answer 6

Type 1 hypersensitivity disorders.

Question 7

An allergy involves cytokines produced by which type of cells?

Answer 7

• Th2 cells
• IgE
• Mast cells
• Eosinophils

Question 8

State some symptoms of asthma.

Answer 8

• Wheeze
• Breathlessness
• Chest tightness
• Cough

Question 9

What are the common allergens of asthma?

Answer 9

• Inhales allergens
• Food
• Drugs

Question 10

State some symptoms of rhinitis.

Answer 10

• Nasal itching
• Blockage
• Rhinorrea
• Sneezing

Question 11

What is urticaria and angiodema?

Answer 11

Itchy, nettle rash - hives.

Question 12

What are urticaria and angiodema triggered by?

Answer 12

• Food
• Drugs (NSAIDs and ACEi)

Question 13

What is eczema?

Answer 13

Erythematous inflammation of the skin.

Question 14

What is anaphylaxis?

Answer 14

Severe allergic reaction.

Question 15

For Type 1 hypersensitivity allergens, list some drugs.

Answer 15

• Penicillin
• Sulfonamides
• Local anesthetics
• Salicylates

Question 16

Explain what happens during the first and second exposure to pollen.

Answer 16

1st exposure: IL-4 causes B cells to produce IgE in response to antigens. IgE binds to mast cells.
2nd exposure: Acute release of mast cells contents causes allergic rhinitis (hay fever)

Question 17

Explain the process of the activation of an allergic response.

Answer 17

1. Allergens enter mucosa and is detected by dendritic cells.
2. Dendritic cells take allergens to lymph nodes. Activation of T and B cells. B cells converted into plasma cell.
3. Plasma cells travel back to mucosa and produce IgE antibodies.
4. IgE binds to mast cells which triggers mast cells degranulation.

Question 18

Explain the mechanism of type 1 hypersensitivity.

Answer 18

IgE-mediated mast cell and basophil degranulation -> release of vasoactive mediaters.

Question 19

What is the main functions of mast cells?

Answer 19

• First-line of defence
• Release granule contents.
• Inflammation

Question 20

What is the role of mast cells during inflammation?

Answer 20

1. Pathogens enter at site of wound which attract mast cells and macrophages. Mast cells release Histamines. Macrophages engulf pathogens and release inflammatory cytokines.
2. Neutrophils and monocytes attracted to wound. Neutrophils undergo phagocytosis. Monocytes promote tissue healing.
3. Pathogen removed.

Question 21

Which two type of cells initiate and inflammatory response?

Answer 21

• Mast cells
• Basophils

Question 22

Where are mast cells found?

Answer 22

Connective tissue surrounding blood vessels and mucosal surfaces.

Question 23

Where are basophils found?

Answer 23

Blood circulation.

Question 24

What effect does mast cell activation and granule release have on the GI tract?

Answer 24

• Increased fluid secretion
• Increased peristalsis

Question 25

What effect does mast cell activation and granule release have on the eyes, nasal passages and airways?

Answer 25

- Decreased diameter - Increased mucus secretion

Question 26

What effect does mast cell activation and granule release have on blood vessels?

Answer 26

- Increased blood flow - Increased permeability

Question 27

What are the granule contents of Mast cells?

Answer 27

- Histamines - Leukotrienes - Inflammatory cytokines - Neutrophil and eosinophil chemokines

Question 28

What are the granule contents of eosinophil?

Answer 28

- Matrix metalloproteinases and collagenases - Fibrotic cytokines - T and B cell attracting chemokines

Question 29

What is the effects of histamine in type 1 hypersensitivity reactions?

Answer 29

- Capillary and venous dilation - Increased vascular permeability - Contraction of smooth muscle.

Question 30

What are the 2 phases of an allergy?

Answer 30

Immediate phase and late phase

Question 31

What are the main processes that occur during the immediate phase of an allergy?

Answer 31

- Mast cell degranulation - Histamine release

Question 32

What are the main processes that occur during the late phase of an allergy?

Answer 32

- Immune response - Eosinophil migration

Question 33

What is the effects of the granules which are part of eosinophils?

Answer 33

- Contain enzymes that are harmful to the cell walls of parasites. - Can damage host tissues

Question 34

What happens during the early phase of an allergic response?

Answer 34

- Mucus production - Vasodilation and swelling - Bronchoconstriction

Question 35

What happens during the late phase of an allergic reaction?

Answer 35

- Recruit immune cells into peripheral tissues - Smooth muscle scarring

Question 36

What is the effect of histamine in the body when pathogens enter subcutaneously?

Answer 36

Inflammation of connective tissue and capillaries.

Question 37

What is the effect of histamines in the body when pathogens enter by ingestion?

Answer 37

- Inflammation of the epithelium and capillaries. - Contraction of intestinal smooth muscle.

Question 37

What is the effect of histamines in the body when pathogens enter intravenously?

Answer 37

Inflammation of the capillaries and connective tissue.

Question 38

What is the effect of histamines in the body when pathogens enter via inhalation?

Answer 38

- Inflammation of epithelium and capillary. - - Contraction of the brochial smooth muscle. - Mucus production