In a paper published in the December 26, 2001 issue of the Journal of the American Medical Association (289; 24; 3083-3088), Alberto Ascherio, MD, DrPH, and colleagues at the Harvard School of Public Health and School of Medicine report on a study of blood samples from a subgroup of women participating in the long-term Nurses’ Health Studies, which have followed the health status of 230,000 registered women nurses since 1976. The group searched for elevated levels of immune antibodies (indicating prior exposure to an infectious agent) against the Epstein-Barr virus and another virus for comparison, searching for a possible association between these viruses and MS. This research group had reported previous studies associating exposure to Epstein-Barr virus (EBV) with MS. Epstein-Barr virus causes infectious mononucleosis.

 A small proportion of the thousands of women enrolled eventually developed multiple sclerosis. Of those, the authors report on 18 whose blood had been drawn before they developed MS. Based on several measurements, on average the 18 women had higher levels than matched controls of antibodies in their blood against portions of the Epstein-Barr virus. The authors also analyzed the blood of 126 cases of MS in which the blood was collected after disease onset, and found significantly higher levels of the antibodies than matched controls but lower levels than those of the women whose blood was collected prior to onset.

 While EBV has been associated with MS and proposed as a possible MS infectious trigger in the past, this is the first published study in which antibody levels could be assessed prior to diagnosis. The authors note that over 90% of Americans have been exposed to EBV and have residual EBV antibodies in their blood, but the vast majority do NOT have MS. They conclude that EBV may serve to increase risk of MS, but that other factors must also be involved.

Conclusion:

This interesting study adds new information to ongoing research focused on discovering what factors trigger MS and how they can be stopped. Other studies have shown associations of MS with Epstein-Barr virus and other viral or bacterial infections, but none of the studies yet prove that a specific virus or bacterium actually causes multiple sclerosis. 

It is possible that the immune dysfunction that leads to MS causes abnormal findings in relation to immune responses to various infectious agents. It is also possible that infections of late childhood may influence the immune systems of susceptible persons to alter defenses and later attack the body’s own brain and spinal cord tissues. 

Further research in this area will hopefully provide insights for better treatments and even ways to prevent multiple sclerosis.