MS-virus link being pursued.

The exact nature of the link between viruses and MS is yet to be unraveled and researchers continue to explore possibilities. One theory is that exposure to certain viruses might set in motion the immune attack which results in MS. Perhaps when the immune system responds to an invading virus, immune system cells mistake myelin protein for the virus and attack it. Or perhaps the antibodies caused by an early viral infection which linger in the nervous system become activated in certain individuals at a later time.

None of these theories has yet been verified, including recent claims from an MS hospital in Overpelt, Belgium. A group of researchers there reported finding a link between MS and the human herpes virus known as HHV-6. HHV-6 causes Roseola, a short-term illness with fever and rash in young children between the ages of 2 and 3. The Belgian scientists speculated that active Roseola antibodies reappeared during adulthood to trigger MS in susceptible people.

Investigators have also reported finding HHV-6 inside oligodendrocytes, the brain cells that make and maintain myelin. Other common herpes viruses, HHV-1 and HHV-2, were also reported in larger percentages in the brain tissue of people with MS. But, as the National MS Society notes, HHV-6 has also been found in the brain tissue of many adults who do not have MS.

While many scientists doubt that MS is triggered by a single virus, the National MS Society is sponsoring additional studies to follow the intriguing possible connections between HHV-6 and MS.