Genetic biomarkers could help detect food allergy

Eosinophilic esophagitis is a painful and serious food allergy in which the esophagus becomes sore and inflamed, restricting food choices and causing weight loss, vomiting, heartburn and swallowing difficulties, often going undiagnosed in young children. Researchers at the Cincinnati Children's Hospital Medical Center have spotted a genetic signature that might help with its diagnosis and lead to potential treatments.

In a study published in the Journal of Allergy and Clinical Immunology, the team profiled the expression of miRNA (short strands of genetic material) in the cells of the esophagus and in a group of patients with eosinophilic esophagitis, including patients with active disease and those treated with glucocorticoids so that their disease was in remission. The results were compared with those from healthy people and people with esophagitis not caused by food allergy.

Compared with people without esophagitis, or with the non-food allergy type of disease, people with eosinophilic esophagitis showed altered levels of 32 different miRNAs in their esophageal cells, with miR-21 and miR-223 the most increased and miR-375 the most decreased. These three miRNAs were most strongly linked with levels of the immune cells known as eosinophils.

The researchers also looked at miRNAs in plasma in people with active disease and disease in remission, and in healthy people, and found changes in miRNA plasma levels in active disease, including miR-223, miR-146a and miR-146b, suggesting that a blood test could be possible.

"The identification of biomarkers specific to eosinophilic esophagitis is a significant advancement for both the diagnosis and treatment of the disease," said Marc E. Rothenberg, M.D., Ph.D., director of allergy and immunology and the Center for Eosinophilic Disorders. "The microRNA signature provides an opportunity for more precise analysis of esophageal biopsies."

Diagnosis of eosinophilic esophagitis is very invasive, including endoscopies under anesthesia, and being able to use miRNA profiles in blood samples would improve people's quality of life. Because treatment with steroids reversed the changes in miRNA levels, these biomarkers could be used to track progression of disease and the efficacy of treatment, which would be useful in the clinic and in drug development, too.

- read the press release
- see the abstract