MS Affects Everyone Differently

Understanding the details can help

MS is a progressive disease that causes damage to the central nervous system, manifested in outward and silent symptoms. Although there is no cure for MS, many treatments are available that can help slow progression of the disease.

How MS affects the body

Relapsing MS is thought to be an autoimmune disease, which means that, instead of defending the body against harmful invaders (such as viruses or bacteria), the immune system attacks the body itself.

nerve with myelin sheath image

Specifically, MS affects the cells of the central nervous system (CNS). Your brain contains nerve cells called neurons, and the nerve fibers are protected and insulated by what is called the myelin sheath. The myelin helps neurons send electrical signals to and from the brain, telling the body what to do.

With MS, immune cells cross the blood-brain barrier, cause inflammation within the CNS, and attack the myelin sheath. This is thought to interfere with the ability of neurons to send signals between the brain and the body. When your brain cannot communicate with the nerves and muscles the way it's supposed to, various symptoms of MS (such as vision problems and difficulty with muscle movement, coordination, and balance) can occur.

What causes relapsing MS?

MS is thought to affect more than 2 million people across the globe. It is about 2-3 times more common in women than in men. An MS diagnosis generally occurs between 20 and 50 years of age, but it can also happen when you're younger or older.

Nobody knows exactly what causes MS, but research is being conducted to investigate:

  • Environmental factors
  • Infectious agents (such as bacteria or a virus)
  • Genetic predisposition (a family history of MS)
  • Ethnicity: although anyone can get Relapsing MS, a large percentage are of Northern European descent


Learn about the symptoms of relapsing MS.... More >>

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TYSABRI® (natalizumab) is a prescription medicine used to treat adults with relapsing forms of multiple sclerosis (MS) to slow the worsening of symptoms common in people with MS and to decrease the number of flare-ups (relapses). TYSABRI increases the risk of progressive multifocal leukoencephalopathy (PML). When starting and continuing treatment with TYSABRI, it is important to discuss with your doctor whether the expected benefit of TYSABRI is enough to outweigh this risk.

Important Safety Information

TYSABRI increases your risk of getting a rare brain infection—called progressive multifocal leukoencephalopathy (PML)—that usually leads to death or severe disability.

Before receiving TYSABRI, it is important to tell your doctor:
TYSABRI can cause serious side effects. If you have any of the symptoms listed below, call your doctor right away:
The most common side effects of TYSABRI are:
These are not all of the possible side effects of TYSABRI. For more information, ask your doctor. To report side effects to FDA, please call 1-800-FDA-1088.

Please see Full Prescribing Information (PDF) including Boxed Warning and Patient Medication Guide (PDF).

This information is not intended to replace discussions with your healthcare provider.