Multiple sclerosis (MS) is a baffling, mysterious disease. It is especially frustrating in that it tends to strike young, healthy persons in the prime of life. Some sufferers also go through periods of time when the disease seems to have completely or nearly completely disappeared–but then it returns.
But now, researchers and scientists are reportedly making sense of some of this debilitating illness’ most baffling characteristics.
MS is one of the major causes of disability in adults under 65 in the United States. The disease attacks delicate nerve cells in the spine and brain that are covered with a fatty, protective sheath called myelin, which functions much like the plastic coating (insulation) on an electrical wire.
Setting Off Immune Response
What sets off the “sclerosing” process — which is part of the body’s immune response — is not known, but for one in 1,600 people between 20 and 40 (60% of them women), inflammation may start to affect the protective myelin, causing sclerosing, or scarring, which can interfere with nerve impulses or stop the nerve from transmitting any information at all. The location of the affected nerves varies from person to person, as does the length of the attacks; although the episodes tend to get worse, and alternate with periods of time when the disease seems to go away entirely (remit).
Scientists have been searching feverishly to discover the causes of MS. Studies of cases confined to certain geographical locations suggest that some causes could be environmental. For instance, more cases are reported in northern Europe, southern Australia, New Zealand, and the northern United States than elsewhere in the world. Why? Nobody is sure. Interestingly, the data seem to suggest that you have to be exposed to an unknown toxin before puberty for the effects to be most likely to manifest.
MS also tends to run in families, suggesting a role for genetics. A virus-type organism also may trigger the destruction of nerve coatings. The immune system certainly seems to be affected, and may hold the key to understanding this disease.
Antibodies to the Rescue?
The word “antibody” is associated with the immune system; and one approach to treatment of MS being developed by biotechnology companies such as Acorda Therapeutics in Hawthorne, New York, is to develop monoclonal antibodies to fill in worn or missing spots in the myelin to restore the nerve to functionality.
“Antibodies are like guided missiles,” says Ron Cohen, MD, president and CEO of Acorda. “Like smart guided missiles, they will kill or lock onto the part of the outer coating of one type of cell only and not others.” Monoclonal antibodies are cloned copies of a single antibody cell, all targeted toward the same cell, be it a bad disease-causing cell or a cell that needs to be “fixed.”
Some antibodies lock onto cancer cells and trigger the immune system to kill the cell. But in recent years, Cohen says, scientists have shown that antibodies come in more than one type. Some trigger the death of a cell. Others act as a signal that says the cell should start doing something it was not doing before the antibody locked onto it. These are called signaling antibodies.
Chewing Up Myelin
In MS, the M1 class of antibodies, being explored by doctors at the Mayo Clinic and Acorda, may fit a class of medical locks, including myelin, which may be “chewed up,” as Cohen puts it, by the patient’s own immune system. “If you strip the myelin off a nerve,” he explains, “it can’t conduct impulses. It may be alive, but it’s in a state of suspended animation.”
The result may be numbness and tingling, which can become paralysis or loss of vision. Sometimes, when the disease is advanced or not in remission, it is difficult for MS patients to work or function. Many, such as comedian Richard Pryor, are confined to a wheelchair.
Acorda is making clones of a class of antibodies that attach to the glial cells that make myelin. “We not sure how, but the antibodies ‘wake up’ the glial cells and say, ‘Make more myelin,'” Cohen says. Other signal antibodies interact with the immune system to get it to quit killing myelin cells. Obviously, the latter is good, but to replace the stripped myelin holds most promise for restoration of function.
Putting Myelin Back
“These antibodies cause the system to put myelin back on the nerve,” Cohen says. Acorda’s goal is to develop one such antibody for human use. They have found a mouse antibody that works this way in mice, and have progressed to finding a human antibody that also replaces mouse myelin, but human trials have yet to begin. “We hope to go to clinical trials in 18 months,” Cohen says. Testing is still in the very earliest of stages, and no evidence yet exists that this human antibody can actually benefit people.
Other scientists have not been idle, either. Three drugs now on the market are intended to slow the demyelinization process. These drugs slow the rate at which a patient’s immune system attacks the myelin, while the Acorda antibodies, it is hoped, will repair any destruction that may have taken place. “We see these therapies as complementary,” Cohen says.
According to the National Multiple Sclerosis Society (www.nmss.org), the symptoms of MS include difficulty walking, pins-and-needles sensations, and impairment of vision.
An MRI (magnetic resonance imaging) test is currently the preferred way to detect the scarred areas, which indicate that the disease may be present. Such areas, however, can also have other causes; and 5% of people with MS have no brain lesions. Usually doctors don’t look for MS unless there have been two attacks (an “attack” being a worsening of a symptom lasting at least 24 hours) at least 1 month apart. They are defining “attack”. I think that placing the parenthetical statement here makes more sense.There should be more than one area of damage to the myelin of the central nervous system, too. Other tests include a spinal tap and electrical studies of the brain. There is no blood test for MS, but blood tests can rule out mimicking diseases such as Lyme disease.
Use common sense. If you start to slur your speech or have trouble walking, consult your doctor.
Article By: Jean Lawrence, Medical Writer