Patients with diarrhea-predominant irritable bowel syndrome appear to share a similar “exhaustion” in their T-cells during a symptom flare, differentiating them from other IBS subtypes, according to a letter published in Gut.

“For the first time, we’ve discovered that in patients with irritable bowel syndrome associated with diarrhea, their T-cells seem to be ‘out of puff’ or run down,” Patrick A. Hughes, PhD, of Adelaide Medical School and the South Australian Health and Medical Research Institute, said in a press release. “These normally active immune cells are less responsive to stimulation, secreting fewer mediators and dividing less. This type of response is often observed in chronic infections.”