Key Points
Yale study links gut microbiome composition to multiple sclerosis risk
Specific bacterial species show different abundance in MS patients
B-cell therapy alters gut microbiome toward healthy profile
Microbiome interactions may explain MS development
The microbiome in the gut comprises trillions of bacteria and other microorganisms that live in our digestive tracts, and are connected to human health and disease.
Researchers from Yale University in the US identified gut bacteria that had significantly different levels of abundance in patients with MS. Compared to healthy individuals, MS patients also had a smaller number of bacteria coated in an antibody known as host immunoglobulin A (IgA).
"The fact that fewer bacteria were coated with IgA in patients with MS suggests that there is perhaps a fundamental disconnect going on with the host-microbe interactions," said Erin Longbrake, Associate Professor of neurology and the study's principal investigator. Longbrake said that "theoretically, environmental risk factors could predispose people to MS because they change the bugs that are in the gut."
For the study, published in the Neurology Neuroimmunology and Neuroinflammation, the team included 43 people who were newly diagnosed with MS and had not started any sort of immune therapy to treat the disorder. These were compared with 42 healthy controls.
Analysis of their stool samples showed that species of Faecalibacterium were less abundant in patients with MS, while species of Monoglobus was more abundant in untreated MS patients.
Of the 43 people with MS, 19 gave the researchers an additional stool sample six months after starting B-cell depletion therapy -- a treatment that destroys immune cells that contribute to autoimmune diseases.
The gut microbiomes of these patients more closely resembled the microbiomes of healthy controls than they had pre-treatment, the researchers found.
"This gives us some clues into the mechanisms underlying how this type of drug works to treat MS," Longbrake said. The findings might help explain why some people develop MS, but not others.
