The Gut Microbiome and Multiple Sclerosis as reported in the Spring issue of NARCOMS Now
"Neurons and immune cells are present in the gut, but they are not the most plentiful living cells there. Also residing in our GI tracts are over 100 trillion separate microorganisms. These include an estimated 10,000 species of bacteria. These organisms, collectively known as the microbiome, have evolved over time while cohabitating with the human body. They can be either beneficial, just neutral (commensal) or pathological (capable of producing illness)."

https://docs.wixstatic.com/ugd/826c66_4290542fa31540dcb5403ec2781da11e.pdf