Question: Please could you define Autoimmunity? Also, do defects in your immune system cause your body to mistake healthy cells/organs such as the brain, and eliminate them? If so, what can be done to treat problems like this?

David Foley answered on 15 Nov 2014:

You’ve pretty much defined autoimmunity in your question. This most commonly affects the body (diabetes, arthritis and psoriasis are all examples) but rarely the brain (Multiple sclerosis affects the peripheral nervous system, but not the brain).

The specific treatment does depend on the precise autoimmune disease. Diabetes is treated with insulin – this is because all the insulin producing cells have been destroyed and we cannot yet replace them.

Arthritis and psoriasis are often treated with steroids and other immunosupressants that dampen the overall response of the immune system. This can lead to increased susceptibility to other infections, however.

Another treatment invovles “mopping up” the proteins that signal to the immune system to attack the cell. An example is Humeria, a powerful anti-TNF antibody that mops up TNF (tumour necrosis factor; despite the name it is a general inflammatory signalling molecule).

Research is ongoing into ways to more specifically modulate our immune system – to suppress it in the case of autoimmune disease and to stimulate it for the treatment of cancer.