A new study from researchers at the University of Illinois Chicago linked the herpes simplex virus type 1 (HSV-1) — an extremely common virus that causes cold sores — with the incidence of multiple sclerosis (MS).
The study — MLKL-OPTN axis regulates herpes virus-induced neurological sequelae — was published in June by Clinical and Translational Medicine. The research said HSV-1 could impact MS by damaging the myelin sheath that protects nerve fibers.
“If you are infected [with HSV-1], then your immune system is constantly locked in battle with the virus,” said Deepak Shukla, professor of ophthalmology, microbiology and immunology at the University of Illinois Chicago, and one of the study’s authors. “And if for any reason you become immunocompromised, the virus can escape and damage your brain.”
“MS is a chronic [disease] of the central nervous system where the immune system attacks the protective myelin sheath, resulting in demyelination and consecutive neurodegeneration,” the study said. “While the exact etiology of MS remains elusive, both genetic predisposition and environmental factors, including viral infections, have been implicated in its pathogenesis. Notably, herpes viruses such as Epstein-Barr virus and varicella-zoster virus have been strongly associated with MS onset and progression.”
The link between HSV-1 — which, once introduced, remains in its human host for that host’s lifetime — has been studied before, researchers said. But this new study “highlights a direct molecular mechanism, a previously unrecognized effector pathway, that connects HSV-1 infection to MS-like demyelinating pathology via dysregulation of the MLKL‒OPTN axis.”
Mice without the optineurin (OPTN) antiviral protein were infected with HSV-1, which “triggered significant myelin loss and MS-like symptoms such as impaired motor coordination and shaking,” said Multiple Sclerosis UK Limited in describing the study. Mice in the control group — who had OPTN and were also infected with HSV-1 — did not develop those symptoms.
