Link shown between Crohn's disease and virus

A new study reveals that all children with Crohn's disease that were examined had a commonly occurring virus – an enterovirus – in their intestines. This link has previously not been shown for this chronic inflammatory intestinal disorder. The findings are being published today in the latest issue of the international journal Clinical and Translational Gastroenterology.

These findings need to be confirmed in larger studies, but they are important, as this connection has never been pointed out before. This paves the way for a better understanding of what might be involved in causing the disease, says Alkwin Wanders, one of the scientists behind the study at Uppsala University and Uppsala University Hospital.

In Sweden several thousand adults live with Crohn's disease, and each year about 100 children and adolescents develop the disorder. The disease affects various parts of the gastrointestinal system and causes symptoms such as stomach aches, diarrhoea, and weight loss – in severe cases fistulas, or strictures in the intestines.

The cause of Crohn's disease is not known. Mutations in more than 140 genes have been shown to be associated with the disorder, but this genetic connection is not a sufficient explanation. Many of these genes play key roles in the immune defence, which has prompted theories that the disease might be caused by impaired immune defence against various microorganisms. In that case, the disease would be a consequence of interplay between heredity and environment.

Recent research has shown that some of the genes that are strongly linked to the disorder are important for the immune defence against a certain type of viruses that have their genetic material in the form of RNA, so-called RNA viruses. Using this as a point of departure, an interdisciplinary research team was established in Sweden to investigate what role this type of virus plays in the disease.

The research team includes the paediatrician Niklas Nyström, the pathologist Alkwin Wanders, virus researchers Gun Frisk and Oskar Skog, the molecular biologist Mats Nilsson, and the geneticist Ulf Gyllensten at Uppsala University and Uppsala University Hospital, along with cell biologists Jonas Fuxe and Tove Berg the paediatrician Yigael Finkel at Karolinska Institutet in Stockholm.

Crohn’s disease is a long-term condition that causes inflammation of the lining of the digestive system.

Inflammation can affect any part of the digestive system, from the mouth to the back passage, but most commonly occurs in the last section of the small intestine (ileum) or the large intestine (colon).

Common symptoms of Crohn’s disease include:

diarrhoea
abdominal pain
fatigue (extreme tiredness)
weight loss

Over time, inflammation can damage sections of the digestive system, resulting in additional complications, such as narrowing of the colon.