Epstein-Barr Virus Increases Risk of MS

While being infected at a young age with Epstein-Barr virus generally causes few, if any, symptoms, delayed exposure into adolescence or adulthood can cause infectious mononucleosis with symptoms that can be quite severe.

Caucasians, Hispanics and African-Americans who have had infectious mononucleosis, commonly known as mono, which is caused by Epstein-Barr virus, may have an increased risk of multiple sclerosis (MS). Independent of other factors that could affect MS risk, such as sex, age, smoking and genetic ancestry, the risk of MS for those who had mono was higher than for those who had not.

A team of scientists working with those at Kaiser Permanente Southern California (Pasadena, CA, USA) recruited 1,090 African-Americans, Hispanic and white people, over a three-year period, with each group having a near balance of healthy people to people with MS or its precursor, called clinically isolated syndrome. Participants had blood tests to check for the Epstein-Barr virus antibody and were asked whether they had ever had mono. Incident cases of MS or its precursor, clinically isolated syndrome (CIS), and matched controls (African-Americans, 111 cases/128 controls; Hispanics, 173/187; whites, 235/256) were included in the study.

Epstein-Barr nuclear antigen-1 (EBNA-1) seropositivity was independently associated with an increased odds of MS/CIS in all three racial/ethnic groups. In contrast, cytomegalovirus (CMV) seropositivity was associated with a lower risk of MS/CIS in Hispanics, but not in blacks or whites. Among African-Americans, 12/111 (11%)of the people with MS, , had mono in the past, compared to 4/128 people who did not have MS,(3%). For Hispanics, 13/173 people (8%) with MS, had mono in the past, compared to 3/187 people (2%) who did not have MS.. Among whites, 48/235 (20%) people with MS, had mono in the past, compared percent to 30/256 people (12%), of those without the disease.

The authors concluded that The consistency of EBNA-1 seropositivity with MS across racial/ethnic groups and between studies points to a strong biological link between EBV infection and MS risk. The association between past CMV infection and MS risk supports the broader hygiene hypothesis, but the inconsistency of this association across racial/ethnic groups implies non-causal associations.

Annette Langer-Gould, MD, PhD, the lead author of the study, said, “While many people had Epstein-Barr virus antibodies in their blood, we found among all three groups, people who also developed mono in their teen years or later had a greater risk of MS. This implies that delaying Epstein-Barr virus infection into adolescence or adulthood may be a critical risk factor for MS.” The study was published on August 30, 2017, in the journal Neurology.

Related Links:
Kaiser Permanente Southern California