#ECTRIMS2016 – Immune Cells Linked to Autoimmunity Found in MS Patients’ Gut

Immune cells, believed to drive autoimmunity, are selectively increased in the gut of patients with multiple sclerosis (MS), along with lower numbers of cells controlling inflammation, suggesting that immune processes in the gut impact MS disease mechanisms.

The study, “The role of gut immunity in multiple sclerosis patients,” was presented at the Young Scientific Investigators’ Session 2 of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) 2016 Congress Sept. 14-17 in London.

Today, few researchers doubt that gut immune processes impact immune mechanisms in the rest of the body, and may contribute to autoimmunity. A common theory is that environmental factors, such as diet and microbes, increase the risk of developing an autoimmune disease in people who carry a genetic risk by changing intestinal immunity.

Many studies have been performed in animal models of MS concerning the role of gut microbiota, but the research team from San Raffaele Hospital in Italy chose to investigate patients directly.

The team recruited 23 relapsing-remitting MS patients and 16 control individuals who underwent an endoscopy for diagnostic purposes. The team analyzed the immune cells found in the gut mucosa and in the blood of these individuals. None of the MS patients had been treated with corticosteroids in the previous six months, and antibiotics in the previous four weeks, as these treatments are known to impact the gut microbiota.

Researchers found Th17 cells, an immune cell type believed to be involved in MS mechanisms in the intestines of MS patients but not in their blood. Also, Th22 cells were found only in the gut. MS patients also had more activated Th17 cells and less anti-inflammatory cells known as regulatory T-cells (Tregs) in their intestinal mucosa, compared to control individuals.

“Our data suggest that there is a selective activation of Th17 cells in the intestinal mucosa of MS patients. These findings validate previous reports in pre-clinical models of MS and provide the first evidence that gut immunity modulate MS pathogenesis in humans,” the research team wrote in their ECTRIMS abstract. “Our next goal is to determine how environmental factors such as diet can modulate MS pathogenesis through alterations of gut microbiota composition and intestinal immunity.”

Investigations on how processes in the intestines can impact immunity are soaring. Earlier this year, researchers showed that MS patients have different gut microbes than healthy people. Another study showed that the gut inhabitants of MS patients tend to be of the kind that trigger inflammation.