The growing understanding of the link between the gut and brain inflammation is perhaps one of the most exciting new avenues in modern medical research. An incredible new study from researchers at the University of Toronto and UC San Francisco has provided a novel insight into the gut-brain connection, revealing the intestine may be the source of immune cells found to reduce brain inflammation in multiple sclerosis (MS) sufferers.

The new study revealed that plasma cells residing in the intestine can produce antibodies known as Immunoglobulin A (IgA). It was established that these IgA plasma cells have the ability to move from the intestine into the central nervous system, and reduce neuroinflammation associated with MS flare-ups.

Alongside a discovery that IgA levels in human fecal samples were lower when patients were suffering from active MS neuroinflammation, the study found that increasing the volume of these IgA plasma cells in mouse models resulted in a resistance to MS-related brain inflammation. All this seems to confidently suggest that MS-related brain inflammation can be, to a degree, modulated by this mechanism that originates in the gut.

"IgAs comprise 80 per cent of all antibodies in the body, yet their exact function is still not fully understood," explains co-author on the new study, Sergio Baranzini. "Showing that IgA-producing B cells can travel from the gut to the brain opens a new page in the book of neuroinflammatory diseases and could be the first step towards producing novel treatments to modulate or stop MS and related neurological disorders."

The new study certainly raises more questions than answers by suggesting these immune cells originating in the gut could be modulating an autoimmune disease in the brain. We don't know if certain gut bacteria play a role in the generation of these IgA plasma cells, and we certainly don't know exactly how significantly the gut microbiome is responsible for the onset of neuroinflammatory diseases such as MS.

The researchers are determined to follow this study with work that hopefully results in clinical outcomes for MS sufferers. These new insights into the gut-brain connection are undeniably revealing how two seemingly disparate parts of the body may be inextricably interconnected. And if these immunosuppressive IgA cells that originate in the gut can be better understood then a vast array of new and exciting treatments may be unlocked.

"If we can understand what these cells are reacting to, we can potentially treat MS by modulating our gut commensals," says Jen Gommerman, senior author on the study. "That might be easier than getting drugs into the brain, which is a strategy that hasn't always worked in MS."

The new research was published in the journal Cell.