Multiple sclerosis (MS) is an immune-mediated disease that is believed by some to be an autoimmune disease. In a healthy body, the immune system sends white blood cells to fight invaders, such as bacteria. An autoimmune disease is when the immune system attacks the healthy cells of your body.
In MS, the immune system attacks the nervous system. Over time, the immune system wears down the protective cover on the nerves, called myelin. This damage is called demyelination or sclerosis. In fact, the term multiple sclerosis means “many scars.”
This damage to myelin can also lead to damage of the underlying nerves, all of which can affect how the nervous system functions. You depend on your nerves to feel, see, move, and think. And this damage may cause changes in every one of these functions. That’s why people living with MS may experience pain, fatigue, or changes in mood.