Celiac disease – the problem with gluten – might be triggered by a virus.

NPR covers an unexpected discovery about an auto-immune condition believed to be genetic – celiac disease. You need to have the right (or the wrong) genes to come down with the gluten sensitivity, but those genes seem to be switched on by a viral infection:

Scientists have known for a while that genetics predisposes some people to celiac. About 30 percent of Americans carry the genes that make them more susceptible to the disease. And yet, only about one percent of Americans have celiac.

Researchers wondered why not everyone with the risk genes gets the disease.

The answer is likely complicated, but one theory has emerged. Perhaps a “viral infection can serve as a trigger to celiac,” explains Dr. Terence Dermody, who chairs the Department of Pediatrics at the University of Pittsburgh, and is an author of the new study published in Science.

He and a team of collaborators, led by Bana Jabri of the University of Chicago, decided to test this in experimental mice. They had been studying reovirus – a common virus that infects most Americans beginning in childhood, yet isn’t considered dangerous. The researchers genetically engineered the mice to be more susceptible to celiac disease. Then they exposed mice to reovirus. At the same time they also fed gluten to the mice.

It turns out their hunch had been right. The mice developed “an immunological response against gluten that mimics the features of humans with celiac disease,” Dermody says. The symptoms of celiac disease include diarrhea and other signs of gastrointestinal distress.

The upside of understanding this possible connection is significant, explains Dr. Bana Jabri, of the University of Chicago, who is a co-author of the new study.

If it’s true that the virus can trigger celiac disease, then young children who carry the risk genes for celiac could be vaccinated against Reovirus. “It may be useful to start thinking about vaccinating people who are at a high risk of celiac disease against [these] types of viruses,” she says.

Links between viral infection and the development of auto-immune disorders such as celiac disease have been proposed before, “but this is the first tractable experimental model to tackle this question,” says Julie Pfeiffer, an Associate Professor of Microbiology at University of Texas Southwestern, who has followed the research, but is not involved in the new study. Given the interest and the findings, “more studies in humans are warranted,” she says.