In an effort to improve diagnostics for multiple sclerosis (MS), researchers at Yale University have identified three methods that they say can target antibodies commonly found in people with the disease.1
Their report is published in the September 27 issue of the journal Proceedings of the National Academy of Sciences.
Delineating the Differences
Antibodies that target myelin are often found in people with MS. But focusing on them as a diagnostic aid is fairly complicated since these antibodies are also found in people without the disease, explained Nancy Ruddle, PhD, a professor of Epidemiology and Public Health and Immunobiology at Yale University School of Medicine, who led the research along with a team of colleagues. "Further complicating the issue, MS may be several diseases of differing [causes]", they wrote, "whereby anti-myelin antibodies may be [disease-causing] in some form of MS, but merely a reflection of tissue damage in others."
Myelin is a substance found in the central and peripheral nervous systems that is rich in protein and lipids. It forms layers around nerve fibers in this part of the body, acting as insulation. Think of a nerve as an electrical cable, the axon—or nerve fiber—as the wire on which nerve impulses are transmitted, and myelin as the insulin around the wire.2
When MS occurs, it is myelin that is the prime target. When it and the underlying nerve fibers are destroyed through the disease's pathological process, it produces the symptoms typically seen in MS.2
It's believed MS is an autoimmune disease,3 and antibodies are types of cells found in the immune system that play a role defending the body against disease-causing organisms. When MS strikes, it's believed certain antibodies and other immune cells mistakenly attack myelin and other areas of the central nervous system instead of organisms that cause disease, like they're supposed to. However, experts are not certain why.3
Unique Form of Myelin
The aim of this study was to try to come up with a better diagnostic approach using anti-myelin antibodies by making distinctions that could help physicians better differentiate those with MS from those without it. Doing so "could provide important information for novel diagnostic tools and therapeutic interventions," Ruddle's group wrote.
Ruddle and her colleagues used mice in their efforts to distinguish between these two types of antibodies.
They used two methods to induce antibodies to myelin in mice, but several different forms of myelin protein were used. In this study, a type of disease found only in rodents, but similar to MS, known as experimental autoimmune encephalomyelitis (EAE), was observed.
The research team found that even though both approaches produced antibodies to myelin in the animals, only one method made antibodies that could cause disease. The researchers found that the disease-causing antibodies reacted with a modified form of myelin protein that was not recognized by the antibodies that did not cause disease. Thus, they were able to distinguish the two types of antibodies using this method.
"These data … may be useful for evaluating the pathogenicity [disease-causing processes] of antibodies in MS patients as an adjunct to diagnosis and treatment," wrote Ruddle's group.
1. Marta CB, Oliver AR, Sweet Ra, Pfeiffer SE, Ruddle NH. Pathogenic myelin oligodendrocyte glycoprotein antibodies recognize glycosylated epitopes and perturb oligodendrocyte physiology. Proc Natl Acad Sci USA. 2005 Sep 27;102(39):13992-7. Epub 2005 Sep 19.
2. National Multiple Sclerosis Society. Myelin. Available at: http://www.nationalmssociety.org/Sourcebook-Myelin.asp. Accessed October 24, 2005.
3. National Multiple Sclerosis Society. What is Multiple Sclerosis? Available at: http://www.nationalmssociety.org/What%20is%20MS.asp. Accessed October 24, 2005.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
