In multiple sclerosis (MS), the immune system attacks the body’s own nerves. Oleic acid, a fatty acid found in many foods, may counteract this autoimmune reaction, a Yale-led study suggests.In the healthy immune system, regulatory T cells manage the immune response by suppressing the\n T cells that cause inflammation. But regulatory T cells are defective in patients with MS, according to previous research from the lab of David Hafler, MD, chair and William S. and Lois Stiles Edgerly Professor of Neurology, and professor of immunobiology. Be- cause the tissues where this regulation takes place are rich in fat, Hafler and colleagues hypothesized that a fat molecule might be involved. \t\t\t\t\t\tAs reported in the Journal of Clinical Investigation, Hafler’s team found that levels of oleic acid were strikingly low in the fat of MS patients. After incubation with oleic acid, regulatory T cells from MS patients regained the ability to suppress T-cell growth in lab dishes. \t\t\t\t\t\tHafler says future studies will investigate whether increasing dietary oleic acid might help MS patients by supporting their regulatory T cells.