4.2 Allergy and autoimmunity

Question 1

allergy:

Answer 1

inappropriate immune response to harmless foreign antigen

Question 2

allergy: 2 types of reactions

Answer 2

1) systemic allergic reaction
2) localized allergic reaction

Question 3

localized allergic reaction

Answer 3

reaction at site of exposure
- skin
- respiratory tract
- GI tract

Question 4

Type 1 allergic disease:

Answer 4

• Most common
• IgE mediated
• immediate-type hypersensitivity​

Question 5

Type Iv allergic disease:

Answer 5

• T cell mediated
• delayed -type

Question 6

Type 1 hypersensitivity spectrum​ of severity:

Answer 6

• Urticaria: skin
  Can progress to:
• Angioedema: subcutaneous tissue/ swelling
  Can progress to:
• Anaphylaxis: Fatal

Question 7

Therapy for systemic hypersensativity​:

Answer 7

• Epinephrine (epi-pen)
• antihistamines (relieve fever, hives)
• steroids (dexamethasone, prednisolone)

*Often administered intravenously​

Question 8

Allergic skin disease​:

Answer 8

Most common type 1 hypersensitivity:
- flea allergic dermatitis
- atopic dermatitis
- feline eosinophilic granuloma complex
- sweet itch in horses

• sometimes in Type IV ( allergic contact dermatitis

Question 9

Flea-allergic dermatitis:

Answer 9

• Type 1 hypersensitivity​ in antigenic components in flea saliva
• dogs scratch
• cats overgroom - hair loss is common sign

Question 10

Canine atopic dermatisis:

Answer 10

• allergic reaction to environment allergens
• dogs become very itchy and cause secondary trauma
• often opportunistic infection also present

Question 11

Sweet itch in horses:

Answer 11

• allergic reaction to midge bites
• often affect the dorsum of the tail base
• intensely​ itchy

Question 12

Allergy testing types:

Answer 12

• intradermal skin test
• serology blood test (allercept)

Question 13

Problem with allergy test?

Answer 13

is making sure that the test is picking up igE because igE is the antibody associated with type 1 hypersensitivity​

Question 14

Allergic respiratory disease:
- cats
-dogs
- horses

Answer 14

cats: asthma
dogs: allergic bronchitis
horses: inflammatory airway disease

Question 15

inflammatory airway disease​ in horses:

Answer 15

• allergic response to mmoldspores in crappy hay
• coughing, wheezing, exercise intolerance

Question 16

Immune-mediated GIT disease:

Answer 16

• Gluten sensitive​
• IBD

Question 17

Gluten-sensitive​​ enteropathy:

Answer 17

• Hypersensitivity to gluten in the ​diet
• chronic diarrhea and weight loss
• common in Irish setter

Question 18

IBD:

Answer 18

inappropriate immune reactivity to protein in diet or antigen coming from microbial flora

Question 19

Mucosal immunity: viruses and bacteria

Answer 19

• Gut is exposed to the virus and bacteria and antigen stimulates a response that generates secretory igA
• is​ transported across the ​mucosal epithelium and forms a neutralization barrier

Question 20

mucosal immunity: parasite

Answer 20

• igE is stimulated and binds to tissue mast cells and protects from parasites trying to get through epithelium

Question 21

mucosal tolerance: harmless antigen

Answer 21

• dietary protein or antigen from microflora
• expect to see tolerance and production of regulatory T cells that produce immunosuppressive cytokines that switch​ off immune repsonse

Question 22

Underlying causes of IBD:

Answer 22

• increased intestinal permeability ( more antigen gets across)
• to much IgE produced against harmless antigen
• IGA Deficiency
• Poor T regulatory cell response
• defective innate immune response to bacteria

Question 23

Ciclosporin =

Answer 23

immunosuppressive​ drug

Question 24

For autoimmune disease to happen:

Answer 24

• a ​breakdown intolerance​e to self antigen
• failure to regulate pathological immune response

Question 25

Susceptibility to autoimmune disease:

Answer 25

- genetic factor (MHC genes play a critical role) - Hormonal factors ( progesterone and estrogen) - environmental factors ( stress, diet, vitamin D)

Question 26

IgE is associated with

Answer 26

allergic disease, NOT autoimmune disease

Question 27

Type II automimunity:

Answer 27

- Production of igM or igG to cell surface antigens or extracellular proteins - autoimmune attack on target cell ( red blood cells, platlets) - autoimmune attack on protein function: antibodies against acetocolyine receptors in myasthenia gravis

Question 28

Type III autoimmunity:

Answer 28

- antibody (igG) binding in solution - immune complex disease - deposition of Ag/Ab complexes in blood vessels - multisystemic immune-mediated disease ex: glomerulonephritis ( fluorscence )

Question 29

Type IV autoimmunity:

Answer 29

mediated by - CD4 TH1 activating macrophages in the abscess of infection - CD8 accidentally​ killing healthy cells that they think are virus but they arent

Question 30

Type IV autoimmunity: Rheumatoid arthris

Answer 30

Rheumatoid arthritis: packed full of: - macrophage - T cells - pro-inflammatory cytokines when activated produce Pro-inflammatory​ cells and secrete collagenase​

Question 31

Articlar cartilage is made of ​

Answer 31

type II collagen

Question 32

What does collagenase do to collagen?

Answer 32

digest it

Question 33

Type IV autoimmunity: Hypothyroidism

Answer 33

- lymphocytic thyroiditis - likely T-cell mediated - they think the thyroid gland is bad and then target and destroy thyroid

Question 34

Type IV autoimmunity: Keratoconjunctivitis sicca:

Answer 34

- dry eye - immune-mediated destruction of lacrimal gland - probably T cell-mediated​ - Treat with ciclosporin eye drops ( immunosuppressive)

Question 35

Treatment of autoimmune disease:

Answer 35

- predinisolone: 1st tablet to use, use in high doses - Ciclosporin (atopica): interferes with T cell signaling - Azathioprine: treat rapidly dividing cells - Cyclophosphamide​: treat rapidly dividing cells