Immediate hypersensitivity

Question 1

5 contribution to rise in allergic disease

Answer 1

1. genes
2. env.
3. lifestyle
4. occupational exposires
5. some meds.

Question 2

3 peices of evidence for genes

Answer 2

1. family history common
2. 70-75% chance of dev. asthma if both parents atopic
3. early dermatitis predicts later asthma

Question 3

5 potential lifestyle involvments

Answer 3

1. hygene - no shift to Th1 type from Th2
2. resp viruses may risk asthma
3. less fruit and veg mean less antioxidants
4. fatty foods may shift to allergic susceptibility
5. food preservative amy affect gut flora

Question 4

what is link with nutrition

Answer 4

good nutrition leads to a better immune system and allergies are a hyperactive immune system

Question 5

how is urban lifestyle involved

Answer 5

more hygienic and thus more of a Th2 env

Question 6

what is a medication involved

Answer 6

Proton pumpis - less acid and don’t degrade allergens as well so they get in

Question 7

3 types of immediate hypersens. reactions

Answer 7

1. Immunologic - IgE mediated
2. immunologic - non-IgE mediated
3. non-immunologic

Question 8

what is non-IgE mechanism

Answer 8

1. substances act directly on mast cells to activate mediator release
   - no need for prior exposure
   - no need for specific IgE
   - often drugs

Question 9

feature of non-immunologic reactions

Answer 9

• complement mediated C3a and C5a

- reactions to blood products and dialysis membranes

Question 10

what is IgE isotype switch

Answer 10

change of one class to another

• constant region changes but the variable region stays the same
• antigen spec. the same, but interacts with different molecules/cells

Question 11

what is outcome of the IgE isotype switch

Answer 11

this becomes the high affinity molecule on mast cells

Question 12

features of IgE mediated rxns

Answer 12

1. requires previous exposure
2. allergen specific IgE produced by plasma cells and released into body
3. IgE binds to mast cells and they release mediators

Question 13

2 important things for reaction to IgE

Answer 13

1. dose - high is worse

2. route of exposure - skin, IV, mouth

Question 14

what are outcomes for IV, subcut, inhal., ingestion

Answer 14

1. IV - systemic histamine release -anaphylaxis
   Subcut -local hist. release - wheal and flare
   inhaled - allergic rhinitis and bronchoconstriction
   ingestion - smooth muscle causes diarrhea and vomiting

Question 15

what happens the next time an allergen is encountered

Answer 15

allergen cross-links with the IgE bound to mast cell and causes it to degranulate

Question 16

where does mast cell bind to the IgE

Answer 16

high affinity receptor

Question 17

what are 3 classes of mediators released from mast cells

Answer 17

1. immediate (stored) - less dangerous - hist., TNF, proteases
2. newly synthesized - lipid mediators, prostaglandins,
3. cytokines - basophils, IL3,4,5, chemokines

Question 18

what is different about late phase

Answer 18

actually inflammatory

Question 19

what is effect of hist

Answer 19

non-lofe threatenening

- wheal, sneeze, conjunctivitis, bronchospasm

Question 20

what is effect of late phase reactants

Answer 20

attract and activate neutrophils - inflamation

Question 21

what is uniphasic anaphylaxis

Answer 21

initial Sx are treated and go away

Question 22

what is biphasic anaphylaxis

Answer 22

after treatment is latent for a period and then returns

Question 23

what is protracted anaphylaxis

Answer 23

keeps coming back after treatment and is associated with increase mortality

Question 24

what should be given in a reaction

Answer 24

anti-inflammatory, because due to the inflammatory late phase reactants