CHICAGO — Antigliadin antibodies may be a useful biomarker for predicting which patients with irritable bowel syndrome will improve on a gluten-free diet, according to research presented at Digestive Disease Week.
“There is growing interest in the role of food as a trigger of symptoms in functional bowel disorders, including IBS. More than 60% of patients with IBS [experience] bloating and abdominal pain after ingestion of certain foods, and within these foods, wheat and gluten may cause symptoms in a subset — not all — IBS patients in whom celiac disease and wheat allergy have been excluded,” María Inés Pinto Sanchez, MD, of the department of medicine at McMaster University and the Farncombe Institute in Ontario, Canada, said during her presentation. Further, studies have suggested that antibodies to native gliadin may be a potential diagnostic marker of response to a gluten-free diet, but this has not been tested in a prospective study in IBS patients.
María Inés Pinto Sanchez
To investigate these potential predictors of response to a gluten-free diet in IBS patients, Sanchez and colleagues evaluated GI transit, GI symptoms, anxiety, depression, somatization and dietary habits in 44 patients with IBS and 23 healthy volunteers before and after 1 month of adhering to a gluten-free diet. All participants were tested for antigliadin antibodies and stratified based on the results. Patients with celiac disease were excluded from the study.
The investigators found that 53% of the IBS patients and 25% of the healthy volunteers tested positive for antigliadin antibodies — either IgA or IgC — and HLA DQ2/DQ8 genetic predisposition was comparable across groups.
After adhering to a gluten-free diet, GI symptoms improved overall in IBS patients who tested positive for antigliadin antibodies, especially constipation (P = 0.01), diarrhea (P = 0.001) and abdominal pain (P < 0.001) while IBS patients who tested negative only experienced improvements in abdominal pain (P = 0.01).
In addition, GI transit was more likely to normalize in IBS patients who tested positive compared with patients who tested negative (OR = 1.75 95% CI, 1.06 - 3.06).
Patients with IBS, regardless of antibody status, experienced comparable improvements in anxiety, somatization and wellbeing, but only patients who were antigliadin positive had reduced depression scores, Sanchez said.
Testing positive for antigliadin antibodies was associated with symptomatic improvement on a gluten-free diet (OR = 8.54; 95% CI, 1.41-48.21), while other factors like changes in motility, dietary adherence or genetic risk were not.
“Antigliadin antibodies may be used as a potential marker to identify ... IBS patients that are more likely to ... improve symptomatically and functionally after gluten-free diet, and strict compliance with the gluten-free diet did not predict improvement, which may suggest that gluten restriction rather that strict gluten avoidance may be sufficient for symptom management in this subgroup of IBS patients,” Sanchez concluded.
Sanchez MIP, et al. Abstract #162. Presented at: Digestive Disease Week; May 6-9, 2017; Chicago.
Disclosures: Sanchez reports no relevant financial disclosures.