Autoimmunty

Question 1

What cell type can override Treg cells?

Answer 1

Th17 by releasing IL-17

Question 2

What’s the difference between an autoimmune reaction and an autoimmune disease?

Answer 2

A disease is pathological and cause harm to tissues/organs

A reaction can be part of the normal bodily processes, attacking cells that are damaged, in the wrong place or neoplastic

Question 3

Autoimmune diseases can be split into 2 categories?

Answer 3

Organ specific with a single tissue specific Ab e.g. Anti-GAD

Non-Organ Specific with non-specific Abs e.g. ANA

Question 4

Give some examples of organ specific autoimmune diseases?

Answer 4

Graves
Hashimotos
Myasthenia Gravis
Pernicious Anaemia
Type 1 DM

Question 5

Give some examples of non-organ specific autoimmune disorders?

Answer 5

SLE
RA
Systemic Sclerosis
Systemic Vasculitis

Question 6

Try to list 5 different mechanisms of autoimmune disease?

Answer 6

1) Cell Mediated Autoimmunity
2) Antibody Mediated (Type 2 hypersensitivity)
3) Immune complex mediated (Type 3 hypersensitivity)
4) Innate Recruitment
5) Molecular Mimicry

Question 7

What conditions operate by cell mediated autoimmunity/

Answer 7

Type 1 DM
Psoriasis
Coeliac disease

T &NK cells are involved

Question 8

What major conditions operate by antibody mediated autoimmunity?

Answer 8

Goodpasture’s Syndrome

Myasthenia Gravis

Question 9

What happens in good pastures syndrome?

Answer 9

Anti-GBM Abs react to type 4 collagen in the basement membrane –> lung haemorrhage & glomerulonephritis

Question 10

What happens in Myasthenia GRavis?

Answer 10

Auto-reactive T cells & Anti-Ach receptor Abs attach to receptors at NMJ –> Muscle weakness & fatigueability

It’s primarily an Ab disorder but T cells are involved hence why we look for and resect thymomas

Question 11

Give an example of an Immune Complex mediated autoimmune disorder?

Answer 11

SLE

Question 12

How does molecular mimicry work?

Answer 12

Pathogen or other molecule (e.g. penicillin) mimics your own cell’s antigen
–> Body attacks that antigen and then your own one too

Question 13

Example of a condition that works by molecular mimicry?

Answer 13

Rheumatic Fever

Strep carries an antigen very similar to that found on muscle cells –> Myocardial damage and myositis

Question 14

How can we treat autoimmune disorders?

Answer 14

Suppression of the damaging immune response

• Anti-inflammatories
• Steroids
• Immunosuppresants e.g. MTX
• Plasmapheresis

Replacement of the function of the damaged organ :

• Stem cell/marrow transplant
• Replacing lost physiological factors
• Organ/tissue graft

Question 15

What is a newer treatment available for autoimmune disease?

Answer 15

T-reg cll therapies n

Question 16

Epidemiology of autoimmune disease?

Answer 16

• 3% of the population
• Affects women more than men
• Affects those between 15-65 (excretion of DM1)

Question 17

what are environmental factors which can lead to autoimmune disease?

Answer 17

• Infections
• drugs
• UV radiation

Question 18

what are genetic components which can lead to autoimmune disease?

Answer 18

• Clusters in families
• common polymorphisms in the MHC complex
• Mutation to the AIRE gene

Question 19

what is the AIRE gene?

Answer 19

• Transcriptional factors expressed by the medullary epithelial cells in the thymus
• Involved in the regulation of the expression of tissue- restricted antigens
• In the absence of AIRE- self-reactive T cells are not eliminated

Question 20

How does central tolerance develop?

Answer 20

-Developing T cells in the thymus
• If they do not recognise MHC are not selected
• If they recognise self peptide + MHC are negatively selected and killed by apoptosis

Question 21

How does peripheral tolerance develop?

Answer 21

• Anergy: T cells in the body which recognise antigen on MHC become anergic/ non-responsive
• T-regulatory cells: inhibit neighbouring T cells by killing them by apoptosis

Question 22

What happens once tolerance has been broken down?

Answer 22

The resulting inflammation may allow presentation of further peptides.
•The immune response broadens and local tissue damage accelerates (epitope spreading).
•This implies that, once the barrier of tolerance is broken down, autoimmune responses may be easier to sustain.

Question 23

How can peripheral tolerance be overcome?

Answer 23

• Inappropriate presentation of self-antigens
• Inappropriate or increased local expression of co-stimulatory molecules
• Alterations in the way in which self-molecules are presented to the immune system