The causes of inflammatory bowel disease (IBD) are poorly understood, but now, scientists have pinpointed a runaway immune response that may underlie the condition in some patients.

IBD, which is characterized by chronic inflammation in all or part of the digestive tract, affects millions of people worldwide. Its principal forms are Crohn's disease, which can occur at any point of the gastrointestinal tract, and ulcerative colitis, which affects only the colon and rectum.