Type II & III hypersensitivity Flashcards Preview

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Flashcards in Type II & III hypersensitivity Deck (31):
1

Type II hypersensitivity is mediated by?

antibodies

2

Which antibodies mediated in Type II hypersensitivity? against what?

IgM and IgG against tissue Antigens(Ag)

3

Type III hypersensitivity is mediated by?

IgM and IgG immune complexes

4

what so bad about immune complexes?

deposition in glomeruli

5

C3b does what?

opsonisation

6

C5b and C5a do what?

C5a: enhance inflammation/phagocytes
C5b: MAC

7

2 main outcomes for Type II hypersensitivity?

1. injury due to MAC
2. abnormal physiology (activation/inhibition)

8

2 example of abnormal physiology Type II hypersensitivity?

Graves Disease
Myasthenia Gravis

9

Classic Type II hypersensitivity injury?

transfusion reactions
tissue rejection

10

what are some transfusion reactions?

haemolysis, shock, nausea, vomiting, pain

11

why are erythrocytes targets for Type II hypersensitivity responses for drug allergies?

drugs like penicillin bound to RBCs/platelets, get targeted by immune system = splenic macrophages causing haemolytic anaemis or thrombocytopenia

12

what is haemolytic disease of newborn?

Mom is Rh -ve, baby is Rh +ve, mom makes antibodies against baby during birth. 2nd birth, mom's antibodies attack fetus RBCs if they are Rh+ve

13

How to treat haemolytic disease of newborn?

Give mother anti-Rh antibodies within 24 hrs of delivery to remove fetal RBCs in circulation

14

What is Goodpasture syndrome?

antibodies made against type IV collagen: basement membrane > glomerular disease

15

What happens in Type II hypersensitivity for Graves disease?

TSH negative feedback loop is useless because antibodies are made that continuously activate the TSH receptor = hyperthyroidism (

16

What happens in Type II hypersensitivity for Myasthenia Gravis disease?

antibodies attack acetylcholine receptors in neuromuscular junction, internalized and degraded (inhibit function)

17

Type III hypersensitivity immune complexes occurs why? 2 reasons

complexes excessively produced
inefficiently cleared

18

How are immune complexes normally dealth with?

cleared by splenic macrophages

19

good efficient immune complexes are usually made up of what antibodies?

IgG with fixed complement

20

which are better? large or smaller immune complexes? why?

large complexes better because they activate complement better, removed from circulation efficiently by RBCs

21

3 reasons why immune complexes not cleared?

excess antigen
law affinity Ab
inefficient complement activation

22

How do immune complexes cause pathology?

deposition on vessel walls > inflammation >complement > activate mast, basophils, platelets

23

3 common outcomes of Type III hypersensitivity?

vasculitis
glomerulonephritis (BMs)
arthritis (joint synovium)

24

Farmer's Lung is e.g. of what kind of hypersensitivity?

Type III hypersensitivity

25

how do you get immune complexes deposited in lungs?

inhaled antigen: mould, plant, animal antigen

26

how do you get kidney, joint, arteries, skin immune complex deposition usually?

autoimmunity

27

Farmer's lung from exposure to?

mouldy hay dust/bacteria (actinomyces)

28

SLE is? what kind of hypersensitivity?

systemic lupus erythematosis, Type III hypersensitivity

29

2 big features seen in SLE? females or males more?

anti-DNA autoantibodies
immune complexes in BMs of kidneys
more females

30

Antibodies against self reasons? 2 reasons

antigen receptor rearrangement is random
tolerance is not perfect

31

2 kinds of tolerance

central: in bone marrow, removal during development
peripheral: T-Regs