Herpes Virus Linked to Multiple Sclerosis

Herpes virus 6A and 6B can infect our brain cells but they do it in different ways

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Researchers at Karolinska Institutet have developed a new method to separate different types of a common herpes virus (HHV-6) that has been linked to multiple sclerosis (MS). 

By analyzing antibodies in the blood against the most divergent proteins of herpesvirus 6A and 6B, these researchers were able to show that MS-patients carry the herpesvirus 6A to a greater extent than healthy individuals.

This is relevant news since as many as 80 percent of all children are infected with the HHV-6 virus before 2 years of age. 

But since it hasn’t been possible to tell the variants apart post-infection, it has been difficult to say whether HHV-6A or B is a risk factor for MS, said these researchers in a related press release.

The findings published on November 26, 2019, in Frontiers in Immunology, indicate ‘a potential role for HHV-6A in MS vaccine development.’

Multiple sclerosis is an autoimmune disease that affects the central nervous system (CNS). The cause of the disease is unclear, but one plausible explanation is a virus tricks the CNS to attack the body’s own tissue.

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HHV-6 has previously been associated with MS, but in those studies, it wasn’t possible to distinguish between 6A and 6B.

HHV-6 infection has been associated with complications of varying severity in hematopoietic stem cell transplant recipients, to a lesser degree in solid organ transplant recipients, and in those who are otherwise immunosuppressed, says the HHV-6Foundation.org.

These researchers have been able to show that HHV-6B can cause mild conditions such as roseola in children, but it has been unclear if HHV-6A is the cause of any disease.

In this study, however, the researchers were able to distinguish between the A and B virus by analyzing antibodies in the blood against the proteins—immediate-early protein 1A and 1B (IE1A and IE1B)—that diverge the most between the 2 viruses.

“This is a big breakthrough for both the MS and herpes virus research,” says Anna Fogdell-Hahn, associate professor at the Department of Clinical Neuroscience at Karolinska Institutet and one of the study’s senior authors, in this press release.

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“For one, it supports the theory that HHV-6A could be a contributing factor to the development of MS.” 

“On top of that, we are now able, with this new method, to find out how common these different types of HHV-6 are, something we haven’t been able to do previously.”’

The researchers compared antibody levels in blood samples of some 8,700 MS-patients against more than 7,200 healthy people whose gender, date of birth, date of the blood sample and other factors matched those with MS. 

They concluded that people with MS had a 55 percent higher risk of carrying antibodies against the HHV-6A protein than the control group. 

In a sub-group of almost 500 people, whose blood samples were drawn before the onset of the disease, the risk of developing MS in the future was more than doubled if they had a 6A viral infection. 

The younger the people were when the virus was first discovered in the blood, the higher the risk was of developing MS in the future. 

HHV-6B, on the other hand, was not positively associated with MS. 

Instead, MS-patients had lower levels of antibodies toward IE1B than those without MS.

Antibodies toward Epstein-Barr virus (EBV), another herpes virus that is also associated with MS, were analyzed with the same method and the researchers were able to show that individuals affected with both viruses had an even greater risk of MS. 

This indicates that several virus infections could be acting jointly to increase the risk of MS.

“Both HHV-6A and 6B can infect our brain cells, but they do it in slightly different ways. 

Therefore, it is now interesting to go forward and attempt to map out exactly how the viruses could affect the onset of MS,” says Anna Fogdell-Hahn.

The research has been financed by grants from the Swedish Research Council, Stockholm County Council, Swedish Brain Foundation, KAW Foundation, Margareta af Ugglas Foundation, MultipleMS Horizon 2020, Multiple Sclerosis Society of Canada and the Swedish Society of Medical Research. Some of the researchers have previously received grants/fees by pharmaceutical companies in various contexts.

Multiple Sclerosis news published by Precision Vaccinations