Multiple sclerosis (MS) is an autoimmune disease that attacks the healthy tissues in the central nervous system (CNS). When MS attacks the nerve fibers and the covering that surrounds and protects the body's nerve fibers (called myelin), nerve impulses are interrupted, causing MS symptoms.
Research is still being done on which immune cells are mounting the attack, the factors that cause the attack, and the sites that appear to be attracted to the myelin to begin the destructive process. There are plenty of Web sites that provide a more thorough scientific description of this process (check out nmss.org, for example), but here's a quick snapshot on how cells called lymphocytes impact the immune system:
The immune system contains a network of lymph nodes, which are tiny glands containing immune cells called lymphocytes. Lymphocytes are normally good guys, but sometimes they can go rogue. This can mean they go after your CNS and cause problems.
While it's not exactly clear how GILENYA® works, it is thought to keep lymphocytes from attacking your central nervous system by lowering the number of lymphocytes circulating in your blood.
Scientists believe that GILENYA is thought to work by keeping some lymphocytes locked up inside the lymph nodes.* If lymphocytes are prevented from reaching the central nervous system, there may be less inflammatory damage to the covering of nerve fibers.
During GILENYA treatment, some lymphocytes are still circulating and available to do their job, watching out for intruders like viruses and bacteria.
If your doctor decides to stop your GILENYA treatment for any reason, the "door" of the lymph node is opened up. Within a few days, the number of lymphocytes circulating in your blood increases, and then gradually returns to original levels — usually within 1 to 2 months.
GILENYA moa video
*This effect was only observed in animal models.