MS: Immune cells from the gut reduce brain inflammation
A type of immune cell that migrates from the gut to the brain appears to reduce inflammation in multiple sclerosis, according to recent research.
Scientists have found that by increasing numbers of the immune cells, they could completely eradicate neuroinflammation in mice with multiple sclerosis (MS).
The migrating immune cells are plasma cells that start life in bone marrow as B cells and undergo a transformation under the influence of microorganisms in the gut.
While previous studies have uncovered these cells in the central nervous system (CNS) of people with MS, they did not explain where they came from or what they were doing there.
Now, researchers at the University of California, San Francisco (UCSF) and the University of Toronto in Canada have found some answers after studying the cells in mice and samples from people with MS.
In a paper that features in the journal Cell, they report how gut-resident plasma cells behave during MS flare-ups.
Insights into the role of IgA antibodies
A feature of plasma cell activity is that they produce Immunoglobulin A (IgA) antibodies.
These anti-inflammatory antibodies play a "crucial role" in preventing tissue damage in several "autoimmune and inflammatory diseases."
The new study brings fresh insights into where IgA antibodies come from and how they work.
"IgAs comprise 80 percent of all antibodies in the body," says study co-author Sergio E. Baranzini, who is a professor of neurology at UCSF, "yet their exact function is still not fully understood."
The researchers found lower levels of IgA in stool samples of people with an active MS flare-up. This is consistent with the notion that normally gut-resident plasma cells migrate to the CNS to suppress active inflammation.
The team suggest that the findings could lead to an MS treatment that reduces brain inflammation by increasing the number of plasma cells in the gut.
