A bacterium that may trigger multiple sclerosis has been identified by a research team from Weill Cornell Medical College and The Rockefeller University. Their study, published in PLoS ONE, is the first to identify the bacterium, Clostridium (C.) perfringens type B, in humans.
The scientists say their study is small and must be expanded before a definitive connection between the pathogen and MS can be made, but they also say their findings are so intriguing that they have already begun to work on new treatments for the disease.
"This bacterium produces a toxin that we normally think humans never encounter. That we identified this bacterium in a human is important enough, but the fact that it is present in MS patients is truly significant because the toxin targets the exact tissues damaged during the acute MS disease process," say the study's authors.
"Work is underway to test our hypothesis that the environmental trigger for MS lays within the microbiome, the ecosystem of bacteria that populates the gastrointestinal tract and other body habitats of MS patients."
The study describes discovery of C. perfringens type B in a 21-year-old woman who was experiencing a flare-up of her MS. The woman was part of the Harboring the Initial Trigger for MS (HITMS) observational trial. C. perfringens, found in soil, is one of the most common bacteria in the world. It is divided into five types. C. perfringens type A is commonly found in the human gastrointestinal tract and is believed to be largely harmless.
C. perfringens types B and D carry a gene (epsilon toxin) that emits a protoxin -- a non-active precursor form of the toxin -- which is turned into the potent "epsilon" toxin within the intestines of grazing animals. The epsilon toxin travels through the blood to the brain, where it damages brain blood vessels and myelin, the insulation protecting neurons, resulting in MS-like symptoms in the animals.
Researchers say they do not know how humans are infected with C. perfringens type B or D, but they are studying potential routes of exposure. The scientists are also in the first stages of investigating potential treatments against the pathogen. A vaccine for humans is possible -- there is already a vaccine available for farm animals, but it requires repeat immunizations and they are also investigating the possibility of developing small-molecule drugs that prevent the toxin from binding to its receptor. Another approach is the development of a probiotic cocktail that delivers bacteria that compete with, and destroy, C. perfringens types B and D.