As you saw before the immune system has a way of identifying self from non-self. When this system breaks down, it can result in an auto-immune disease.

During auto immune diseases, the T and B cells contain receptors which match markers on healthy self cells. Some auto immune diseases can Organ specific, only attacking specific organs.

Rheumatoid arthritis (seen to the right), is caused by T cells and antibodies attacking the connective tissue.

Causing inflammation and swelling in the joints.

In Grave’s disease antibodies produced attach to receptors on the thymus which are normally stimulated by the pituitary gland.

This causes the thyroid to be over-stimulated and produce large amounts of thyroid hormone causing the individuals metabolic rate to skyrocket.

Apart from an overactive metabolism, in some cases Grave’s disease can also cause bulging eyes.

Multiple Sclerosis (MS) is caused by T cells and antibodies attacking the Myelin sheath, preventing the rapid conduction between neurons.  

MS can lead to fatigue, numbness, paralysis, loss of vision and deterioration of brain function.

MRI scan show brain lesions throughout the brain.

Type 1 diabetes is an auto-immune disease. T cells and antibodies attach to specific receptors on Beta cells in the pancreas.

This results in the death of Beta cells, and thus a decrease in insulin production.

We can overcome this through insulin injections.