Autoimmunity

Question 1

What is tolerance (in relation to immunity)?

Answer 1

The body’s regulation of self attacking

Question 2

As a population level females are more susceptible to autoimmune conditions than males. T/F?

Answer 2

True

Question 3

What is autoimmunity?

Answer 3

Breakdown of self tolerance leading ti aberrant immune response against self tissue

Question 4

Why are autoimmune conditions self perpetuating?

Answer 4

In normal immune reactions, the immune response will terminate once the foreign particle triggering the response has been dealt with. However, since in an autoimmune condition the immune system is attacking self tissue, the trigger if the attack never goes away and so the attack is self perpetuating

Question 5

The mechanisms of self tolerance are multifactorial. T/F?

Answer 5

True - they involve genetic predisposition and environmental factors

Question 6

Give examples of organ specific autoimmune conditions

Answer 6

Hashimoto thyroiditis
Addisons disease
Atrophic gastritis
Guillan barre syndrome
Multiple sclerosis
Type I diabetes mellitus
Thyrotoxicosis

Question 7

Give examples of systemic autoimmune comditions

Answer 7

RA
Scleroderma
Systemic lupus
Mixed connective tissue disease
Sjogrens syndrome
Dermatomyositis

Question 8

What is the dofference between organ specific and systemic autoimmunity?

Answer 8

Organ specific autoimmunity is an autoimmune attack against self antigens of a given organ which results in damage to that organ’s structure and function
Systemic autoimmunity has widespread antigens as the target for autoimmune attack and damage affects structures such as blood vessels and cell nuclei

Question 9

Treatment for most autoimmune disease focusses on treating inflammation rather than the actual autoimmunity. T/F?

Answer 9

True

Question 10

Give an example of an autoimmune condition where the symptoms are treated rather than the actual cause of the autoimmunity

Answer 10

Type I diabetes mellitus

Question 11

What is the relationship between infection and autoimmunity?

Answer 11

Autoimmunity can sometimes develop after an imfection is eradicated by the immune system but this us not neccessarily caused by the jnfection
In some cases (such as type I diabetes mellitus and multiple slcerosis) infection can help prevent autoimmunity

Question 12

What is the autoantibody target in graves disease?

Answer 12

Thyroid stimulating hormone receptor

Question 13

What is the autoantibody target in myasthenia gravis?

Answer 13

Acetylcholine receptor

Question 14

What is the autoantibody target in idiopathic thrombocytopenia purpura?

Answer 14

Platelets

Question 15

What is the autoantibody target in guillain barre syndrome?

Answer 15

Gangliosides

Question 16

What is the pathophysiology of graves disease?

Answer 16

Thyroid hormones are regulated by thyroid stimulating hormones, the binding of these to their receptor stimulates the synthesis and secretion of more thyroid hormone
In graves disease an autoantibody against the TSH receptor is produced causing constitutive expression of the receptor leading to overstimulation of thyroid hormone

Question 17

What is the pathophysiology of myasthenia gravis?

Answer 17

Autoantibodies bind to acetylcholine receptors and degrade and block them to prevent the passage of an impulse at the neuromuscular junction leading to loss of muscle contractiom

Question 18

Describe the theory of molecular mimicry with reference to gullain barre syndrome

Answer 18

The theory suggests that a molecule is expressed on somtheing that is non self which is a molecular mimic for a molecule that is self and thus causes the mounting of the immune system against self
GBS is derived from autoantibodies which target gangliosides - sugar molecules which exist on many cells
C.jejuni bacteria have a molecule of lipoligosaccharide which exists on its cell membrane and is a moleculear mimic to a ganglioside of the PNS
Once the bacterial infection has been cleared by the immune system, immune cells start to recognise the PNS ganglioside as a bacterial antigen and so attack it

Question 19

Describe the role of the cytokine Tumour jecrosis factor alpha in rheumatoid arthritis

Answer 19

It is involved in:
endothelial cell activation
Leukocyte activation of macrophages, natural killer cells and T cells
Fibroblatst activation
Nociceptor gating
Recruitment of tissue cells such as osteoclasts, keratinocytes and enterocytes

Question 20

How can drugs be used to perturb the cytokine system in autoimmune conditions?

Answer 20

An antibody can be created to bind to and neutralise the cytokine
Part of an antibody can be fused to the cytokine receptor to create a decoy receptor
The transduction of the signal pathway can also be blocked