When the immune system goes wrong

Question 1

what is immediate hypersensitivity and what is it mediated by

Answer 1

allergy

mediated by IgE, mast cells and Th2 responses

Question 2

What is the immediate hypersensitivity response due to

Answer 2

mast cell degranulation and histamine release. If in skin->wheal and flare

Question 3

What is the Th2 response to allergenic disease

Answer 3

pollen taken up by APC->processed and presented as peptides to T cell receptors on CD4->activation leads to Th2 response->B cell activated->class switch to IgE and differentiate to plasma cells->when pollen arives, binds to IgE on surface mast cell->potent activation of stimulus for mast cells which degranulates all of inflammatory mediators diffsued out into local areas->symptoms=sneezing, wheal+flare

Question 4

Common diseases and therapies

Answer 4

Diseases-asthma, perennial rhiniitis, allergic eczema

Therapies-antihistamines, beta 2 adrenoreceptor antagonist, corticossteroids

Question 5

Rare diseases and therapies

Answer 5

Disease: anaphylaxis
Therapies: desensitisation, monoclonal antibody

Question 6

Autoimmunity what

Answer 6

loss of immunological tolerance to self components

Question 7

What are the two types of autoimmune diseases and give examples of it

Answer 7

organ specific-type 1 diabetes, grave’s disease

non organ specific-rheumatoid arthritis, systemic lupus erythematosus

Question 8

What is autoimmunity

Answer 8

Loss of immunological tolerance to self components

Question 9

what are serum antibodies used for

Answer 9

diagnostic tool, monitoring disease activity, predicting future disease, may be pathogenic
(usually IgG class)

Question 10

What is the proof of autoimmunity

Answer 10

Passive transfer of disease by immune effectors (e.g. T cells, antibodies)
Clinical responsiveness to immune suppression or reestablishment of tolerance

Question 11

How does grave’s disease work

Answer 11

usually thyroxine act as feedback to prevent excess TSH but thyroid gland keep making thyroxine in unregulated way->hyperthyroidism->bulging eyes, fast heart rate, weight loss, hyperactivity

Question 12

How does myasthenia gravis work

Answer 12

patients develop autoantibodies against ACh receptor->damage receptor->transmission impaired, insufficient engagement with ACh receptor-> no or poor contraction causing muscular weakness and fatigue

Question 13

How can autoantibodies be passed on from mother to child

Answer 13

if mother has grave’s disease, IgG antibodies against TSH receptor passed onto child. Same with myasthenia gravis

Question 14

How is type 1 diabetes T cell mediated

Answer 14

B cell autoantigens taken up by APC and presented to CD4->activation of Th2->mediate inflammation
B cell present autoantigen directly to CD8->kills B cell
Failure Treg to suppress

Question 15

Are primary and secondary immunodeficiencies inherited/acquired and are they rare/common

Answer 15

primary=inherited defect=rare

secondary=acquired defect=common

Question 16

Are primary and secondary immunodeficiencies inherited/acquired and are they rare/common

Answer 16

primary=inherited defect=rare

secondary=acquired defect=common

Question 17

give examples of primary immune deficiencies and what are they caused by

Answer 17

Di George-thymus doesn’t form
SCID-Pre B and Pre T cells don’t form, lack of cytokines and surface receptors
CGD-neutrophils are meant to be bacteriocidal by reactive O2 compound but O2 compound doesn’t form due to single gene defect. Surround bacteria cell but not kill
Hypergammaglobulinemia-single gene defect of CD40 ligand on T lymphocyte->absence means can’t communicate with B lymphocyte->productive B lymphocyte response not made->plasma cells not develop

Question 18

How does AIDS arise from HIV and how can it be treated

Answer 18

virus infects CD4 through CD4 receptor->CD4 no. decline->antiviral CD8 brings CD4 infection under control to extent->HIV infection+antiviral cytotoxic CD8 means that CD4 wiped out->CD8 decline too
Highly Active Antiretroviral Therapy

Question 19

What is iatrogenic immune deficiency

Answer 19

Immune deficiency caused by medical treatment therapy. Often opportunistic infections caused by monoclonal antibody therapy

Question 20

What causes cancer

Answer 20

Too much immune surveillance (Treg), immune surveillance to combat cancer cells stop working

Question 21

How can cancer be treated

Answer 21

PDL1 on cancer cell and PD1 on effector cells can interact if there is antibody to PD1 or PDL1 as the stop signal for immune surveillance can be taken away->cancerous cells removed