Teaching Tolerance to T Cells

Autoimmune diseases result from a cruel mistake: the patient’s immune defenders, notably the T cells, attack the very tissues they should protect. In rheumatoid arthritis, it’s the joints; in diabetes, the pancreas; and in multiple sclerosis, the brain and spinal cord. For some reason the immune cells botch their central mission, which is to distinguish self from nonself. Now researchers at a number of institutions are testing a novel approach to restraining the traitorous T cells. It’s based on a simple principle: You are what you eat.