immune disease 2 (W12)

Question 1

association between autoimmune disease?

Answer 1

having one increases likeliness for having another

Question 2

how can autoimmunity start

Answer 2

self antigens become modified
microbial antigens resemble self
hidden antigens can be exposed by damage
inflammation breaks anergy (stimulating bystander lymphocytes)

Question 3

susceptibility genes for autoimmunity and example diseases?

Answer 3

MHC alleles (AS, type 1 diabetes, SLE, RA)

Question 4

tissue targeted autoimmunity diseases?

Answer 4

type 1 diabetes
MS
graves’ disease
myasthenia gravis
primary biliary cholangitis

Question 5

multisystem autoimmunity diseases?

Answer 5

SLE
RA

Question 6

2 antibody mediated reactions (damaging)

Answer 6

binding of antibody to own cells
hypersensitivity reaction

Question 7

hypersensitivity reaction example?

Answer 7

haemolytic anaemia: antibodies bind to red blood cells (due to molecular mimicry of recent viral infection) or antibody binds to specific drug-protein complex on red cell surface. antibodies tag these cells for removal even though they are healthy

Question 8

disease examples where autoantibody binds to cell surface receptor? explain?

Answer 8

graves disease - stimulates TSH receptor leading to hyperthyroidism
Myasthenia gravis - blocks Ach receptor leading to neuromuscular weakness

Question 9

what occurs if transfused blood is not the right type

Answer 9

anti-A or anti-B antibodies bind to foreign red cells, induce complement, causing red cell lysis, inflammation in the circulation, haemolysis and intravascular coagulation. System wide cytokine storm and shock.

Question 10

which blood group can be given to anyone? why?

Answer 10

O - lacks A and B antigens

Question 11

which blood group can receive any blood type? why?

Answer 11

AB - lacks A and B antibodies

Question 12

rhesus reaction?

Answer 12

IgG response to protein. rhesus negative (RhD-) mother has RhD+ baby, risk of mother being exposed to RhD+ blood cells. problem for next pregnancy as now has anti-RhD antibodies that will react to future RhD+ babies.

Question 13

damage from antibody binding extracellular targets

Answer 13

antigen-antibody complexes become saturated in the circulation, leads to deposition (small blood vessels in particularly joints, skin). Complement usually breaks these up but it can exceed their capacity.

Question 14

unsensitised vs sensitised hypersensitivity?

Answer 14

unsensitised - haven’t been exposed to allergen protein
sensitised - has been expensed to allergen protein before

Question 15

chronic antigen exposure - autoimmunity disease example?

Answer 15

SLE - nuclear autoantigens from dying cells

Question 16

chronic antigen exposure - chronic infection example?

Answer 16

infectious endocarditis

Question 17

damage from cytotoxic T cell killing - autoimmunity example?

Answer 17

type 1 diabetes:
CTL kill pancreatic islet beta cells (target insulin-related peptides)

Question 18

damage from cytotoxic T cell killing - hypersensitivity examples?

Answer 18

coeliac disease
allergic contact dermatitis

Question 19

coeliac disease?

Answer 19

sentinel intraepithelial CD8 T cells kill intestinal epithelium stressed by cytokines from Th1 cells sensitised to modified dietary gliadin (idk what this means)

Question 20

allergic contact dermatitis?

Answer 20

manifests 2-4 days after re-exposure. red plaques, vesicles, acute oedema, evolving to dry scaly skin. effector memory T cell reaction to neoantigen. sensitised cytotoxic T cells kill keratinocytes that have bound to an allergen (eg nickel from bracelet, topical drugs etc).

Question 21

damage from Th cell activation of macrophages - example disease?

Answer 21

some sarcoid cases