Aberrant immune response

Question 1

what is hypersensitivity type 1

Answer 1

an excessive immune response

Question 2

what is responsible for hypersensitivity type 1

Answer 2

IgE and mast cells largely

Question 3

describe the response in hypersensitivity type 1

Answer 3

resting mast cells have granules that contain histamines
when a stimulus arrives, the mast cell releases the histamines and other inflammatory compounds
IgE antigen complex binds with stimulus -> triggers degranulation event
granule contents expunged

Question 4

what is hypersensitivity type IV mediated by

Answer 4

T cells

Question 5

Which hypersensitivity types are antibody mediated

Answer 5

I (IgE)
II (IgG/ IgM)
III (IgG/ IgM)

Question 6

give an example of type 1 hypersensitivity

Answer 6

seasonal hay fever, food allergies, drug allergies, local and systemic anaphylaxis

Question 7

give an example of type II hypersensitivity

Answer 7

red blood cell destruction after blood transfusion with mismatched blood types

Question 8

give an example of type III hypersensitivity

Answer 8

rheumatoid arthritis

Question 9

give an example of type IV hypersensitivity

Answer 9

type I diabetes

Question 10

what is an organ-specific autoimmune disease

Answer 10

autoimmune attack of self-antigens of a given organ
damage to organ structure and function

Question 11

what is a non-organ specific autoimmune disease

Answer 11

widespread self-antigens are targets for autoimmune attack
damage affects structures such as blood vessels, cell nuclei etc

Question 12

autoimmunity definition

Answer 12

a misdirected immune response that occurs when the immune system goes awry and attacks the body itself

Question 13

describe type I diabetes as an autoimmune disease

Answer 13

organ specific
alpha cell -=> glucagon
delta cell -> somatostatin
beta cell -> insulin
effector T cell recognises peptides produced by ß cell specific proteins and triggers apoptosis
- insulin can no longer be produced

Question 14

describe grave’s disease as an autoimmune disease

Answer 14

organ-specific (thyroid gland)
thyroid hormones regulated by TSH
weight loss, sweating
triggering auto-antibodies bind the the TSH receptor and continuously trigger production of TH

Question 15

describe the normal functioning of TSH

Answer 15

Thyroid hormones regulated by thyroid-stimulating hormones (TSH) from pituitary gland
TSH binds to receptor + stimulates synthesis of thyroid hormones
- Negative feedback loop then switches of TSH production
Homeostatic control

Question 16

describe TSH control in someone with Grave’s disease

Answer 16

non-regulated activating auto0antibodies that bid the the TSH receptor
leads to overstimulation of thyroid hormones

Question 17

describe asthma as an autoimmune disease

Answer 17

inflammatory/ structural cells -> mediators -> effects
- narrowed airway
- muscle contraction, mucus production, inflammation

Question 18

describe the pathophysiology of asthma

Answer 18

chronic inflammation of the lower airways
thickening of BM
increased goblet cell activity
smooth muscle hypertrophy/ thickening
epithelial shedding
airway occlusion (mucosal plug)
mucosal infiltration of T cells/ eosinophils/ others

Question 19

describe covid-19 as it progresses to an autoimmune disease

Answer 19

viral infection
SARS-CoV-2
hyperinflammatory state
- some patients
- more associated with poor outcomes
- result of immune system overworking
‘cytokine storm’

Question 20

list some risk factors that contribute to the cytokine storm

Answer 20

COPD (lung disease)
CAD (coronary artery disease)
obesity (BMI >40)
diabetes
chronic kidney disease
old age (>60)