Researchers Kevin C. O’Connor, PhD of Harvard Medical School and colleagues recently reported in the journal Brain, the lack of evidence directly linking Epstein-Barr virus (EBV) infection in the brains of people with multiple sclerosis. However, it does not refute past research that demonstrates the possibility that EBV could be a risk factor in developing MS.

EBV is a herpesvirus fairly common in humans (95% of adults between 35 and 40 years of age have been infected). It causes infectious mononucleosis (fever, sore throat, and swollen lymph glands) and other disorders. Individuals who have been exposed to EBV carry a latent infection throughout their lives, in both the immune system and in the throat. The virus retains its ability to infect new people through saliva and is generally transmitted by kissing.

“Our finding that CNS EBV infection was rare in multiple sclerosis brain indicates that EBV infection is unlikely to contribute directly to multiple sclerosis brain pathology in the vast majority of cases,” researchers concluded.

There has been a considerable amount of research (since 1981), however, pointing to an association between past EBV infection and an increase in susceptibility to MS.

In a 2006 study reported in the Archives of Neurology, investigators at Harvard and Kaiser Permanente found that individuals who had elevated antibody titers (a laboratory test that measures the presence and amount of antibodies in blood) against EBV were twice as likely to develop MS up to 20 years later

In 2007, investigators from Italy and the United Kingdom reported in the Journal of Experimental Medicine of finding traces of EBV in postmortem brains examined from people with various forms of MS.

Past research has also shown that latent EBV infections may become reactivated in patients with MS. A 2000 study highlighted in Neurology by Wandinger and colleagues found that more than 70% of 19 patients who had relapses during the study period also had reactivations of EBV during this time. “The results demonstrate an association between EBV reactivation and disease activity in MS patients over time, and suggest that EBV might play an indirect role in MS as an activator of the underlying disease process,” researchers reported.

But the role of EBV in MS has yet to be fully understood. One theory to explain how EBV is involved in MS is called molecular or epitopic mimicy. This theory is explained in detail on the Web site www.mult-sclerosis.org.

The idea behind this is that a small section of one of the viral proteins resembles a small section of one of the proteins in myelin. Such small sections are known as epitopes and are the means by which the immune system identifies foreign invaders for destruction. One theory is that the immune system detects the identical epitopes in myelin, it is unable to recognize that they belong to self-proteins, and attacks them. This results in the damage seen in MS lesions–– (http://www.mult-sclerosis.org/EpsteinBarrvirus.html).

This entry was posted on Thursday, September 17th, 2009 at 9:32 am and is filed under Studies. You can follow any responses to this entry through the RSS 2.0 feed.