Multiple sclerosis is an autoimmune neurodegenerative disease of the brain and spinal cord resulting in CNS demyelination affecting 2.8 million people worldwide and 23,000 Australians. There are about 1000 new cases diagnosed in Australia each year and the accumulation of disability can be devastating with an estimated 50 to 80% of patients ceasing full-time work within 10 years. The condition is 3 times more common in women and is most often seen between the ages of 20 and 40 years. The damage in multiple sclerosis is caused by a type IV hypersensitivity reaction and may reflect molecular mimicry with activated T cells crossing the blood-brain barrier and attacking CNS myelin which is produced by oligodendrocytes (myelin in the peripheral nervous system is made by Schwann cells).