Scientists say a “seemingly innocuous” virus can trigger lifelong intolerance to gluten, raising hopes of a vaccine against coeliac disease and related auto-immune conditions such as type 1 diabetes.
University of Chicago researchers have found that a strain of “reovirus” sparks a perpetual immune reaction to gluten, a protein found in wheat. People with coeliac disease risk serious complications, from bone damage to liver disease and even blood cancers, if they eat gluten.
While the causes of the disease are complex, genetic predisposition is a major factor. The new study unravels the mechanisms that turn viral infection into a “key initiating event”, the university said.
The research was published this morning in the journal Science. Team leader Bana Jabri said the immune system was still maturing in the first year of life.
“Getting a particular virus at that time can leave a kind of scar that has long term consequences,” Professor Jabri said. “This study shows that a virus that is not clinically symptomatic can still do bad things to the immune system and set the stage for an auto-immune disorder — coeliac disease in particular.”
Gluten is difficult to digest and provokes the immune system more than other proteins. The new study suggests intestinal viruses can induce the immune system to overreact, triggering lifelong intolerance.
In experiments on mice, two viral strains induced protective immunity, but one — known as “type 1 Lang” — also triggered gluten intolerance. The researchers also analysed coeliac disease patients and found they had much higher levels of antibodies against reoviruses than people without the disease.
Patients with the excess antibodies also overproduced a protein implicated in gluten intolerance. The findings point to a vicious combination of virus and suspect genes, which skews the immune system just as babies are being weaned from breast milk.
“For those genetically predisposed to coeliac disease, the combination of an intestinal reovirus infection with the first exposure to gluten could create the right conditions for developing the disease,” the university said.
The findings follow a study last year linking various viruses to coeliac disease, and help explain why gastrointestinal infections can lead to the condition. “We are now in a position to precisely define the viral factors responsible,” Professor Jabri said.
People with other auto-immune conditions, such as juvenile diabetes, are also at elevated risk of developing coeliac disease. The findings raise hopes of a common vaccination against these illnesses.