New research has identified a specific form of the herpes virus that is linked to multiple sclerosis.
The herpes viruses HHV-6A and HHV-6B are closely linked but have different properties, according to the Swedish researchers. Both can be latent and reactivate later in life, causing severe illness including encephalitis. Less is known about the early signs of HHV-6A, but it has previously been reported to be linked to multiple sclerosis.
Scientists at the Karolinska Institutet, Sweden, have now succeeded in separating the HHV-6A from B viruses serologically, providing a clearer view on their respective roles in multiple sclerosis.
They undertook a population based study looking at the different serological responses. It involved blood samples of about 8,700 multiple sclerosis patients and more than 7,200 healthy people whose sex, date of birth, date of blood sample and other factors matched those of the multiple sclerosis patients.
Blood antibodies against the proteins of herpesvirus 6A and 6B were compared, showing that multiple sclerosis patients carry the herpes virus 6A “to a greater extent than healthy individuals”.
Results were published in Frontiers in Immunology yesterday (26 November). The authors say this points to a role for HHV-6A in the development of multiple sclerosis.
"This is a big breakthrough for both the multiple sclerosis and herpes virus research," says Dr Anna Fogdell-Hahn. “For one, it supports the theory that HHV-6A could be a contributing factor to the development of multiple sclerosis.
"On top of that, we are now able, with this new method, to find out how common these two different types of HHV-6 are, something we haven’t been able to do previously."
Engdahl, E. et al. Increased serological response against human herpesvirus 6A is associated with risk for multiple sclerosis. Frontiers in Immunology November 2019, doi: 10.3389/fimmu.2019.02715
https://www.frontiersin.org/articles/10.3389/fimmu.2019.02715/full
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