Hypersensitivity

Question 1

Describe events in early and late phase of anaphylaxis

Answer 1

Early phase within minutes- secodnary to mast cell degranulation
Late phase over 2-24 hours with erosinophils, neuts and T cell infiltrate

Question 2

What does desensitisation achieve in Type 1 reactions?

Answer 2

Force class switch to Th1 , produce blocking IgG4s and increase Treg cells

Question 3

Describe how type 2 reactions work?

Answer 3

Antibodies against antigens on cells, non-IgE, bind and then

• opsonised for phagocytosis
• ADCC via NK cells
• complement activation

eg blood transfusion ABO mismatch, Grave’s disease, ITP, MG

Question 4

Describe type 3 events?

Answer 4

IgG, Ag, and C3b form immune complexes. If large enough deposit in vessel walls, nephrons, synovial membranes

eg serum sickness reacting to non human proteins after 4-10 days
eg SLE
eg post strep GN
eg hepatitis
eg RA
eg Farmers lung
eg arthus reaction- 4-12 hours post vax get induration and oedema and pain from immune complex deposition in perivascular area

Question 5

examples of type 4 hypersensitivity

Answer 5

TB
sarcoid
schisto
crohn’s

Question 6

What drives TH1?

Answer 6

IL-12

Question 7

What drives Th2?

Answer 7

IL-4

Question 8

What drives T reg?

Answer 8

TGF-beta… also spits this out!

Question 9

What drives Th17 development?

Answer 9

IL-1, IL6, IL-23

Question 10

What do TH1 make?

Answer 10

IL-2
IFN gamma
TNF alpha

Question 11

What do Th2 make?

Answer 11

IL-4
IL5
L9
IL10
IL13

Question 12

Role of IL-17 cells

Answer 12

respond to EXTRACELLULAR bacteria and fungi

Neutrophil recruitment

Question 13

What do IL-2 responses do?

Answer 13

Allergy response
IL_5–>eosinophils, larger parasite response
IL-4 –>extracellular parasite response

Question 14

What does a TH1 type promote?

Answer 14

cell mediated immunity
phagocytosis microbes
eradicate INTRACELLULAR organisms

Question 15

How can glucagon be useful in someone with anaphylaxis who is resistant to adrenaline also taking beta blocker?

Answer 15

Glucagon increases cAMP, avoids adrenergic receptor and creates same result as adrenaline

Question 16

How long do you have to hold someone post anaphylaxis?

Answer 16

At least 4 hours post resolution of all signs and symptoms and or last dose adrenaline

Question 17

causes objectively reproducible symptoms or signs initiated by exposure to a defined stimulus at a dose tolerated by normal subjects

Answer 17

hypersensitivity

if it is an immunologic phenomenon initiating then it counts as an allergy

atopy is where there is immunological reactivity in which IgE is produced in response to ordinary exposure to common allergens- not in itself a disease

Question 18

Heparin
Tryptase
Chymase
Heparin

released from what, when

Answer 18

Immediate release mast cells

Question 19

Newly synthesised from mast cells after cross linking

Answer 19

leukotrienes and prostaglandins

also protein messengers

Question 20

FIRST thing immunotherapy does?

Answer 20

Reduce mast cell and basophil activity for degranulation
Later on reduce Th2 response by increasing T reg
After that reduce tissue mast cells and late phase response

Will increase IgG4, maybe IgA
Early increase then decrease in IgE

Question 21

Outcomes in Omalizumab

Answer 21

Reduce exacerbation rates
Reduce ICS dose and SABA use
Improve sx and QOL
Improve FEV1 small
Response quite heterogenous

Binds FREE IGE, reducing cell bound IgE

Question 22

Chronic idiopathic urticaria and angioedema- what to treat with and what to avoid?

Answer 22

No steroids

Responds to high dose antihistamines

Question 23

Acute treatment for anaphylaxis?

Answer 23

0.4mg of
1 in 1000 adrenaline
repeat in 15-20 mins as needed

Question 24

Treatment for TEN

Answer 24

stop cause
supportive care often ICU
IVIG FIRST LINE

other things can happen- cyclophosphamide, plasmapheresis

Question 25

MOA ondansetron

Answer 25

5HT3 antagonist

CONSTIPATION MOST COMMON SIDE EFFECT

Question 26

Intractable hiccups use

Answer 26

chlorpromazine or haloperidol

Question 27

iron reduces absorption of what med?

Answer 27

Thyroxine

Question 28

Most common cause of erythema multiforme?

Answer 28

HSV

also penicillin , sulfonamides, carbamazepine, allopurinol, NSAIDS, nevirapine, OCP

sarcoid, strep, malig