IBS risk higher with atopic disease, low mast cells

Low mast cell counts and atopic disease are associated with increased risk for irritable bowel syndrome, according to data presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting in San Antonio.

Researchers evaluated data from 100 patients who received endoscopies and biopsies with immunostaining for mast cell tryptase. Incidence of atopic disease and diarrhea-predominant irritable bowel syndrome (IBS-D) was recorded.

“Recent literature supports the association of intestinal mast cells and atopic disease in IBS-D,” the researchers wrote. “To date, however, the specific count of mast cells (per high power field [HPF]) at which these mast cells become clinically significant is unknown.”

Investigators noted an increased risk for IBS-D among patients with a history of atopic disease (OR=4.2), food allergy (OR=6.96) or allergic rhinitis (OR=12.0). Among patients with fewer than 19 mast cells/HPF, atopic patients were more likely to have IBS-D than nonatopic patients (OR=4.2).

After adjustment for atopic disease, patients with 15 to 19 mast cells/HPF were twice as likely to have IBS-D than those with less than 15 cells/HPF (OR=2.05). After adjustment for mast cell counts, patients with atopic disease were more likely than those without atopic disease to have IBS-D (OR=4.55).

“IBS-D has many potential etiologies,” the researchers wrote. “This study demonstrates the significance of both mast cell count and atopic disease status in the diagnosis of IBS-D. Prospective studies matching atopic disease status, mast cell number and response to treatment are currently under way to further define this subset of IBS.”

For more information:

Mittel RJ. #632: The Relationship Between Atopic Disease, Mast Cell Counts and Irritable Bowel Syndrome-Diarrhea Predominant (IBS-D). Presented at: The American Academy of Allergy, Asthma & Immunology Annual Meeting; Feb. 22-26, San Antonio.