Link shown between Crohn's disease and virus
In a new study, researchers in Stockholm and Uppsala reveal a previously unknown link between Crohn's disease in children and a commonly occurring virus – an enterovirus – in the intestines. The findings, which are presented in the scientific periodical Clinical and Translational Gastroenterology, paves the way for a better understanding of what might be involved in causing this chronic inflammatory intestinal disorder.
The cause of Crohn's disease is yet unknown. 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. 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 physicians and researchers from Uppsala University, Uppsala University Hospital and Karolinska Institutet. In the present study the researchers investigated whether the RNA virus were present in children with Crohn's disease. They focused in particular on the prevalence of enteroviruses, a group of RNA viruses that are known to infect the intestinal mucous lining.
The study comprises nine children with advanced Crohn's disease and fifteen children with incipient Crohn's disease symptoms. The results show significant amounts of enteroviruses in the intestines of all of the children with Crohn's disease, whereas the control group had no or only minimal amounts of enteroviruses in their intestines. Similar results were obtained using two different methods. Enteroviruses were found not only in intestinal mucous linings but also in so-called nerve cell ganglia in deeper segments of the intestinal wall. Receptors for a group of enteroviruses were also found in both the intestinal mucous linings and nerve cell ganglia, which may explain how the virus can make its way into the nerve system in the intestine.
The researchers now want to go on to examine larger groups of patients and more control individuals. They also want to pursue experimental research to investigate the link further. The study was funded by, among others, Uppsala County Council, the Swedish Society for Medical Research, Cancerfonden, Karolinska Institutet, and the Swedish Research Council. Study leaders at Karolinska Institutet were Associate Professor Jonas Fuxe, Department of Medical Biochemistry and Biophysics, and Adjunct Professor Yigael Finkel, Department of Clincal Science and Education (KI SÖS).
Human enterovirus species B in ileocecal Crohn's disease.
Clin Transl Gastroenterol 2013 Jun;4():e38