Researchers find further evidence linking Epstein-Barr virus and risk of multiple sclerosis

http://www.eurekalert.org/pub_releases/2010-03/hsop-rff030410.php

Public release date: 4-Mar-2010
Contact: Todd Datz
Harvard School of Public Health

First long-term study among individuals not infected with EBV suggests EBV infection likely to be a cause of MS, not a consequence
Boston, MA – Researchers from the Harvard School of Public Health, Walter Reed Army Institute of Research, and a team of collaborators have observed for the first time that the risk of multiple sclerosis (MS) increases by many folds following infection with the Epstein-Barr virus (EBV). This finding implicates EBV as a contributory cause to multiple sclerosis. The study appears in an advance online edition of the journal Annals of Neurology and will appear in a later print edition.

Hundred of thousands of individuals not infected with EBV were followed up for several years through repeated blood samples collections. Researchers were then able to determine the time when individuals developed an EBV infection and its relation to MS onset. "The recruitment of individuals before they were infected with EBV and following up with them for several years is the critical methodological aspect that makes this study qualitatively different from all previous work," said Alberto Ascherio, senior author of the study and professor of epidemiology and nutrition at Harvard School of Public Health and professor of medicine at Harvard Medical School.

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"The observation that MS occurred only after EBV is a big step forward," said Alberto Ascherio. "Until now we knew that virtually all MS patients are infected with EBV, but we could not exclude two non-causal explanations for this finding: that EBV infection is a consequence rather than a cause of MS, and that individuals who are EBV negative could be genetically resistant to MS. Both of these explanations are inconsistent with the present findings," said Ascherio.

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