NEW YORK -- Multiple sclerosis occurs when your own immune cells attack your brain and spinal cord. It can cause a variety of neurological symptoms that can leave a person disabled.

But an experimental treatment may slow the disease.

Many patients with MS take weekly -- or even daily -- injections of medication to keep their symptoms in check. But current treatments only work about 30 percent of the time.

Doctors are studying an antibody treatment called Campath. The antibodies target the immune cells that are attacking the patient's own body. Researchers hope that when the antibodies hit their targets, they'll turn those cells off.

"The preliminary studies of Campath showed that there was a very immediate and sustained ability of Campath to reduce inflammation in the brain of MS patients," said Dr. Brian Apatoff of New York Weill-Cornell Medical Center.

Apatoff said that those findings could mean fewer symptoms for MS patients.

"We're hoping that early control of brain inflammation and clinical attacks will slow long-term disability that can occur over time," he said.

Apatoff also said there is another potential benefit to the drug. Campath is so potent that patients only need one treatment a year.

There are some potential side effects, however. Campath affects the immune system, so patients could be more susceptible to infections. So far, studies haven't shown that to be a major problem. But more research is needed before the drug is approved for treating MS.

A large, multicentral trial of Campath is now under way around the country.