Clinical Autoimmunity NOT FINISHED

Question 1

How can we classify autoimmune diseases?

Answer 1

1. mechanism by which loss of tolerance has occurred
2. presence and effects of autoantibodies
3. extent to which different organs are affected
   - tissue specific vs systemic

Question 2

In the disease state there is a breakdown in the mechanisms which prevent the activation of T helper cells. What are the 3 mechanisms that can be affected and lead to autoimmunity?

Answer 2

1. Ignorance e.g. disruption of eye barrier –> sympathetic ophthalmia in contralateral eye
2. Failure of Tregs to suppress self-reactive T helper cells
   e. g. in RA suppressive function is impaired, allowing autoreactive cells to escape from regulatory control
3. Innapropriate antigen presentation - if associated danger present from dead bacteria or when an infectious agent products a protein peptide that mimics a self protein

Question 3

What are the 5 ways that autoantibodies can cause autoimmune disease?

Answer 3

1. complement dependent lysis of target cell
2. opsonisation
3. formation of immune complexes
4. blockade of receptors for physiological ligands
5. stimulation of cell surface receptors