According to the Crohn’s & Colitis Foundation, irritable bowel disease (IBD) affects 1,6 million Americans, with the number increasing each year. Approximately 70.000 new cases are diagnosed every year.
Robin Dart, consultant gastroenterologist at Guy’s and St Thomas’ NHS Foundation Trust, stated, “There is currently no cure for IBD, and for a large proportion of the patients I treat, persistent relapses are distressing and have a significant impact on their daily lives.” Despite improvements in therapy, relapse rates remain high despite the fact that most treatments focus on reducing inflammation.
The good news is that recent advancements in genetics, immunology, and microbiology have provided scientists with a much better understanding of the disease and, consequently, how to best direct research efforts toward devising innovative treatments for it.
Dart and a team of researchers from the Francis Crick Institute, King’s College London, and Guy’s and St. Thomas’ NHS Foundation Trust have identified a subset of specialized T cells, V-gamma-4 (Vg4), that plays a crucial role in gut-lining preservation and repair.
Dart stated, “We must begin targeting other areas, such as repairing the gut barrier, and T cells, particularly Vg4 cells, may provide a means to do so.”
The researchers discovered a significant difference in gamma delta () T cells between healthy and IBD colon tissue samples obtained from 150 patients. In healthy intestines, they discovered a thriving population of Vg4 T cells, whereas in the tissue of IBD patients, this subpopulation of cells was distinct and in many instances significantly diminished.
Professor of Immunobiology at King’s College London Adrian Hayday, the study’s primary author, likened gut T cells to a vacuum cleaner that cleans up damage caused by infections and toxins entering through a door that must remain open for food to pass. Damage accumulates if T cells are not functioning properly, leading to inflammation and potentially cancerous changes that can grow unrestrained.
If these protective immune cells are depleted, the intestine becomes susceptible to the progression of disease. People with inadequately managed IBD have an increased risk of colorectal cancer.
Hayday stated that the relationship between uncontrolled IBD and particularly severe forms of colon cancer is poorly understood. “Therefore, it is fascinating that the key immune cell subset that we have identified as lacking in IBD may also be identical to the gut T cells characterized by another group in Milan as having a potent capacity to attack colon cancer cells. We believe that abnormalities in these cells could relate the two diseases.”
After an episode of inflammation, IBD patients who had a restored, functional Vg4 T cell population were less likely to experience a relapse than those who did not.
These findings have the potential to lead to a more effective clinical treatment for IBD and provide more acute disease progression and recovery indicators.
The research was published in the journal Science.
