Publication date: Nov 27, 2019
Credit: Marvin 101/Wikipedia Researchers at Karolinska Institutet have developed a new method to separate between two 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, the researchers were able to show that MS patients carry the herpesvirus 6A to a greater extent than healthy individuals.
But since it hasn’t been possible to tell the two variants apart post-infection, it has been difficult to say whether HHV-6A or B is a risk factor for MS. 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 two viruses.
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 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.
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.