Multiple Sclerosis
What is multiple sclerosis?

We now know more than ever about multiple sclerosis, but researchers are still searching for its cause. MS is believed to be an autoimmune disease. Autoimmune means that the body’s immune, or defense, system mistakenly attacks its own tissue. With MS, your immune system attacks the nerve tissues in your central nervous system (CNS), which consists of the brain and spinal cord.

Understanding the role of the CNS

The brain and spinal cord contain cells called neurons, which send signals within the CNS to other parts of the body. These signals control physical functions, such as balance and muscle coordination, as well as thinking and other abilities. Signals pass through neurons by way of nerve fibers called axons. And, axons are protected by a covering, called myelin, which helps the axons carry signals. (For a closer look at the parts of a neuron, see Figure 1 below.)

Figure 1. Healthy neuron




With MS, damage to neurons disrupts the body’s ability to send signals and causes MS-related symptoms. Symptoms may vary because of the location and extent of the damage. Today, researchers believe both inflammation and neurodegeneration contribute to the destructive actions of MS.1-4 (For a closer look at the destructive actions of MS, see Figure 2 below.)

Figure 2. Damage from Inflammation and Neurodegeneration




The destructive actions of MS

Inflammation is activated by the immune system. This causes swelling and damage to the myelin. When the myelin is lost, scars called scleroses are left behind. This is where the name multiple sclerosis comes from.

Permanent damage, and the loss of neurons and axons, is known as “neurodegeneration.” Researchers are learning more about this complex process every day. It’s very important to know that neurodegeneration occurs early in MS and continues throughout the course of the disease.1-4 Recent studies have shown that neurons and axons are also damaged and even destroyed during the course of MS, even when inflammation is not present.1-4 These findings, MS experts have concluded, support starting therapy early.1,2

Who has MS?
Worldwide, MS may affect more than 2 million individuals, and in the United States, approximately 400,000 people live with MS. It can affect all races, but is more common among people of northern European ancestry. Most people are diagnosed with MS between the ages of 20 and 50, while women are 2 to 3 times more likely to have MS than men.