The gastrointestinal (GI) tract is a remarkable organ: it resides on the inside of our bodies, but is regularly in contact with the outside world by virtue of what we ingest. It is quite incredible that the immune cells of the GI tract are not activated more regularly by the many foreign products it encounters every day. Only when the GI tract encounters an intruder that risks causing disease do the immune cells of the GI tract spring into action.
That is, of course, under normal circumstances. In people with Crohn’s disease, the normally tolerant immune cells of the GI tract are activated without provocation, and this activation leads to chronic or relapsing — but ultimately uncontrolled — inflammation.
Crohn’s disease: A primer
First described by Dr. Burrill B. Crohn and colleagues in 1932, Crohn’s disease is a complex inflammatory disorder that results from the misguided activity of the immune system. It can involve any part of the GI tract from the mouth to the anus, but most commonly involves the end of the small intestine.
Depending on the precise location of GI inflammation, Crohn’s disease may cause any number of symptoms including abdominal pain, diarrhea, weight loss, fever, and sometimes blood in the stool.
Treatment options for Crohn’s disease have evolved dramatically since Dr. Crohn and colleagues first described the condition, but the basic principle has remained the same: reduce the uncontrolled inflammation. Early approaches to treatment involved nonspecific anti-inflammatory medications such as corticosteroids, which have many potentially serious side effects outside the intestines.
Today, a number of newer therapies exist that act more specifically on the immune system to target inflammatory pathways known to be active in Crohn’s disease. These newer drugs, termed biologics, are antibodies that block proteins involved in specific inflammatory pathways relevant to Crohn’s disease.