Immuno 1: Hypersensitivity and allergy : part 2

Question 1

Give an example of how a type IV hypersensity rreaction might occur

Answer 1

Antigen is presented on an APC APC presented to Th1, which releases IFN-g, FGF and IL-2 IFN-g activates macrophages which release TNF FGF activates fibroblast which casues angiogenesis and fibrosis IL-2 causes cytotoxic T lymphocytes to release perforin

Question 2

Nickel is a type II mediated hypersensitvitiy (improve)

Answer 2

F. Type 4… as it contact hypersenstivity (contact dermatits) inflammation only where the nickle is present e.g. if a nickel thimble was worn

Question 3

Outline the immune reactant for each hypersensitivty reaction

Answer 3

I- IgE II-IgG III- IgG IV- Th1/Th2/CTL

Question 4

t/f inflammation is part of all immune reactions

Answer 4

T

Question 5

What is inflammation and what is a common feature of it

Answer 5

This is the body’s response to tissue injury * It is a rapid attempt to bring the body’s defences to the site of injury * A common feature of inflammation is immune cell recruitment (sites of injury/infection) and activation * Once the immune cells reach the site, they release cytokines that leads to the features of inflammation * Inflammatory mediators include complement, cytokines, etc.

Question 6

What are the signs of inflammation

Answer 6

Redness Heat Swelling Pain

Question 7

What are the features of inflammation

Answer 7

Vasodilatation, increased blood flow Increased vascular permeability Inflammatory mediators & cytokines Inflammatory cells & tissue damage

Question 8

Increased vascular permeability is caused by which mediators

Answer 8

C3a, C5a, histamine, leukotrienes

Question 9

Which cytokines are involved in inflammation

Answer 9

IL-1, IL-6, IL-2, TNF, IFN-γ

Question 10

Which chemokinesa re involved in inflammation

Answer 10

IL-8/CXCL8, IP-10/CXCL10

Question 11

What can happen to cells during inflammation

Answer 11

Inflammatory cell infiltrate Cell trafficking – chemotaxis Neutrophils, macrophages, lymphocytes, mast cells Cell activation

Question 12

Overall, which 4 things occur in infkamation

Answer 12

Increased vascular permeability Cytokines Chemokines Inflammatory cell infiltrate

Question 13

What is atopy

Answer 13

a form of allergy in which there is a hereditary of constitutional tendency to develop hypersensitivity reactions (e.g. hay fever, allergic asthma, atopic eczema) in response to allergens (atopens). Individuals with this predisposition - and conditions provoked in them by contact with allergens - are described as atopic.

Question 14

What is the prevalence of atopy

Answer 14

Common - prevalence of atopy is 50% in young adults in UK

Question 15

How does the severity of allergy vary

Answer 15

mild occasional symptoms severe chronic asthma life threatening anaphylaxis

Question 16

T/f the genetic risk factors of atopy is usually monogenic

Answer 16

~80% of atopics have a family history Polygenic

Question 17

Which genes are linked to raised IgE, asthma atopy

Answer 17

genes of IL-4 gene cluster (chromosome 5) linked to raised IgE, asthma, atopy

Question 18

Which genes are linked to atopa and asthma

Answer 18

genes on chromosome 11q (IgE receptor) linked to atopy and asthma

Question 19

Which genes are linked to eczema

Answer 19

genes linked to structural cells linked to eczema (filaggrin) and asthma (IL-33, ORMDL3, CDHR3)

Question 20

What are the environmental risk factors for atopy

Answer 20

Age - increases from infancy, peaks in teens, reduces in adulthood Gender - asthma more common in males in childhood, females in adults Family size - more common in small families Infections - early life infections protect Animals - early exposure protects Diet - breast feeding, anti-oxidants, fatty acids protect