Scientists have made progress in understanding the genetic basis of multiple sclerosis.
Professor Doron Merkler, of the University of Geneva, Switzerland, and colleagues set out to explore the relationship between genetic and environmental risk factors in the development of the disease.
"We decided to analyse the infectious factors by studying the auto-immune reactions provoked by different pathogens," said Professor Merkler. "This was to try to pinpoint an element that might influence the development of multiple sclerosis where there has been an infection".
The team injected two different pathogens that trigger the immune system, a virus and a bacteria, into healthy mice. This showed an identical immune reaction from the lymphocytes called CD8+ T, the team report. But only the mouse infected with the viral pathogen developed an inflammatory brain disease comparable to multiple sclerosis.
Next, they looked at how the expression of the genes in the CD8+ T cells varied based on which pathogen activated them. This process showed that the DNA-binding factor, TOX, was only expressed in cells activated by the virus.
They explain: "We found that the inflammation environment influences the expression of TOX in T lymphocytes, and that it could play a role in triggering the illness."
The study appeared in Immunity yesterday (15 May). Professor Merkler believes the research gives important insights into the understanding and treatment of auto-immune diseases.
She says: "Our brains have a limited regenerative capacity, which is why they have to protect themselves against the body’s immune reactions, which can destroy its cells by wanting to fight the virus, creating irreversible damage. The brain then sets up barriers that block the passage of T lymphocytes."
Merkler, D. et al. Immunity 15 May 2018
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