L17

Question 1

what is asmtha an example of

Answer 1

type 1 hypersensititity

Question 2

features of asthma

Answer 2

• Airway hypersensitivity
  Lung epithelium inflammation, smooth muscle contraction, mucus production
  IgE - mediated !!

Question 3

mast cell activation: effects on GI tract

Answer 3

increased fluid secretion
increased perstalsis

diarrhea vomiting

Question 4

process of type 1 allergen

Answer 4

Phase 1:
- exposure to allergen
- stim of Th2
- which make Il-4
- which help Bcells make IgE that recognise the allergen
- IgE associates w mast cells in mucosal & connective tissue vie FceR

Phase 2
- allergen binds to IgE on mast cell
- releases its chemicals

Question 5

mast cell activation: effects on airways

Answer 5

decreased diameter
increased mucus secretion

wheezing coughing etc
swelling and mucus secretion

Question 6

what are the chemicals released by mast cells

Answer 6

histamines!
cytokines
prostaglandins
leukotirenes

Question 7

mast cell activation: effects on blood vessels

Answer 7

inc blood flow
inc permeability

= inc fluid in tissues = inc flow of lymph to lymph nodes
= more cells and protein in tissues
= inc effector response in tissues

Question 8

what is a systemic response to alleren called

Answer 8

anaphylaxis
can be caused by lots of histamine

Question 9

antibodies associated with type 2 hypersensitivity

Answer 9

IgG mainly
some IgM

Question 10

type 2 hypersensitivity what does it react to with examples

Answer 10

react with antigens on cells or tissue
Blood transfusion reactions
Haemolytic disease of the newborn
Haemolytic anaemia
Drug induced hypersensitivity

Question 11

blood transfusion reactions

Answer 11

IgM mediated
- binds to transfused RBCs
- complement is activated
causing fever chills nausea etc

Question 12

Haemolytic disease of the New Born

Answer 12

Rh -ve mum
baby Rh +ve
any mixing of blood can cause Rh antigens to be made
2nd baby might be attacked by these antibodies

Question 13

hwo can Haemolytic disease of the New Born
be prevented

Answer 13

giving mother anti-Rh Ag antibodies before birth.

Question 14

what is an example of systemic Type 3 hypersensitivity

Answer 14

e.g. infection
malaria, serum administration = serum sickness

Question 15

example of local type 3 hypersensitvity

Answer 15

repeated inhalation of the disease
e.g. pigeon fancier’s disease - dried poo antigens

Question 16

how is type 4 different

Answer 16

doesnt involve antibodies

Question 17

what cells does Type 4 incolvve

Answer 17

Th, Tc and macrophages

Question 18

what can type 4 be a result of

Answer 18

contact hypersensitivity reactions
poison ivy, nicel, etc.

Question 19

3 types of tests for allergy

Answer 19

• skin prick test
• ELISA to test for antigen specific IgE
• patch test - for type 4 hypersens

Question 20

what is atopy

Answer 20

presence of IgE in serum
predisposed to allergy

Question 21

genetics?: what is concordance in identical twins

Answer 21

60%
and likelihood increases with two atopic parents

Question 22

genetics?: what gene is involved with birch pollen allergy

Answer 22

HLA-DR5
MHC gene

Question 23

genetics?: genes for what other things have been implicated

Answer 23

genes for IL4, FecR, epithelial barrier funciton

Question 24

exposome

Answer 24

kinda like ur genome but enviroment
= the measure of all the environmental influences and associated biologic responses through the life span

Question 25

what has the hygeine hypothesis evolved into

Answer 25

old friend’s hypothesis

Question 26

features of old firend’s hypothesis

Answer 26

• sewage, drainage
• pesticides
• storage and proecessing of crops
• hormones and antibiotics
• western diet that affects microbiome

Question 27

evidence for old friends theory

Answer 27

• Babies given significant antibiotics in early life more likely to develop allergies (altered microbiome)
• Very low prevalence of asthma in populations highly exposed to microbial environments (farm children and Amish populations)

Question 28

treating allergy symptoms

Answer 28

anti histamine
steroid anti inlamm drugs
adenaline (epi pen)

Question 29

Low dose allergen therapies (de-sensitisation)

Answer 29

Intra-muscular injection of low dose allergen, monthly for 2-5 years
Raise IgG, rather than IgE

Question 30

Antibody therapy:

Answer 30

Duplimab to block cytokine (IL4) that promote Th2 cell activation of B cells

Question 31

Oral Tolerance:

Answer 31

used in food allergies
Low doses of ingested antigen is used to re-train the immune system to be tolerant of allergens.