Prevalence of Anti-deamidated Gliadin Peptide Antibodies in Asian Patients With Irritable Bowel Syndrome

BACKGROUND/AIMS: Non-celiac gluten sensitivity has been increasingly recognized as a predisposing factor for irritable bowel syndrome (IBS)-like symptoms in Western populations where celiac disease (CD) is relatively common. In Asia where CD is rare, we wish to determine the prevalence of gluten protein associated serology in IBS patients, which has not been formally studied, and its relation to histological and human leukocyte antigen (HLA) markers. METHODS: We reviewed a consecutive cohort of Asian patients with IBS, who had undergone serologic testing for IgA against deamidated gliadin peptide antibodies (IgA DGP) and IgA anti-endomysium antibodies, and who also had duodenal biopsies during clinical workup. In addition, a subset of Chinese patients with positive serology was further tested for HLA-DQ2 and HLA-DQ8. RESULTS: Of 186 patients, 34 (18%) were positive for IgA DGP; bloating, abdominal pain, belching and diarrhea were the most commonly reported symptoms but diarrhea as the most bothersome symptom was significantly more common in IgA DGP positive patients. Mildly increased intra-epithelial lymphocytes on duodenal biopsy was also more common (29% vs. 9%, P = 0.001). Nine of 21 Chinese patients tested as IgA DGP positive undertook HLA-DQ2/DQ8 testing, with only 2 being positive for HLA-DQ8. All patients with positive IgA DGP reported symptom improvement with gluten withdrawal. CONCLUSIONS: We have described a series of Asian, mainly Chinese, patients with IBS who were tested positive for IgA DGP, and improved on a gluten exclusion diet. We believe this is the first report of non-celiac gluten sensitivity in Asia, a region where CD is uncommon.