For the first time, a biological pathway leading to celiac disease has been described, raising potential for preventive measures including a vaccine.
A study published online Thursday in Science describes how an untimely infection of an otherwise innocuous virus can cause an immune response to gluten, leading to the autoimmune condition that affects 3.2 million Americans, or 1 percent of the U.S. population.
The study identified a reovirus strain that triggers an immune response, which, in turn, renders the person intolerant of gluten, a dietary protein in wheat, barley and rye. The only current treatment for celiac disease is avoidance of foods containing gluten.
With 30 percent of people being genetically predisposed to celiac disease, the fact that only 1 percent of the population develops the condition pointed to a potential trigger that has now been identified.
One leader of the study, Terence Dermody, chairman of the department of pediatrics at the University of Pittsburgh School of Medicine, said it would make sense that introduction of gluten-based food at a time when the infant or young child develops an asymptomatic infection of the reovirus could explain the problem.
In that scenario not addressed directly in the study, the immune system responding to a strain of reovirus also encounters the poorly digested gluten protein. Slow digestion of gluten can engage the immune system even in those without celiac disease. But for those with celiac disease, the inflammatory response can lead to destruction of the lining of the small intestine, potentially leading to death.
The study involved mice but results were coordinated with analysis of humans with celiac disease, who showed higher levels of antibodies to the reovirus, all of which helped confirm the findings.
"We are now in a position to precisely define the viral factors responsible for the induction of the autoimmune response," said Dermody, who also serves as scientific director at Children's Hospital of Pittsburgh of UPMC. "When a virus that's not terribly pathogenic attacks at the same time that a new food is introduced, the immune system is tricked. It is thinking that the food is a foreign invader and elicits an immune response to it. So it's all about timing."
Only 17 percent of those believed to have celiac disease have been diagnosed.
Celiac disease long has posed a mystery to medical researchers about how the body becomes allergic to the protein found in wheat, one of world's most abundantly consumed foods used to make bread, cereals, desserts and beer. Gluten's sticky, elastic nature makes it hard to digest but allows bread to be produced in loaves.
