Human herpes virus 6 and multiple sclerosis: a Finnish twin study

Area of Science:

• Neurovirology
• Immunology
• Genetics

Background:

• The etiology of multiple sclerosis (MS) remains unknown, despite research into genetic and environmental factors.
• Human herpes virus 6 (HHV6) is a potential candidate due to its neurotropic nature, ability to cause demyelination, and capacity for latency and reactivation.
• The Finnish National Twin Cohort provided a unique resource for studying HHV6 and MS in genetically similar individuals.

Purpose of the Study:

• To investigate the potential association between Human Herpes Virus 6 (HHV6) infection and the development of Multiple Sclerosis (MS).
• To analyze HHV6 DNA and antibody responses in serum and cerebrospinal fluid (CSF) of MS patients and their healthy twins.

Main Methods:

• PCR was used to detect HHV6 DNA in serum and CSF samples from MS twin pairs.
• Enzyme-linked immunosorbent assay (ELISA) was employed to analyze Immunoglobulin (Ig) G and M responses against HHV6.
• Samples were collected from twins during a clinical remission phase of MS.

Main Results:

• No HHV6 DNA was detected in any serum or CSF samples.
• High prevalence of IgG antibodies against HHV6 was observed in both MS patients and healthy twins.
• One MS patient showed IgM positivity in serum, while healthy twins did not; all CSF samples were negative for IgG and IgM.

Conclusions:

• Detection of HHV6 DNA or antibodies in CSF during MS remission is improbable.
• The study does not rule out HHV6 reactivation during MS exacerbations.
• Acute HHV6 infection remains a potential trigger for MS development prior to clinical manifestation.