Tu1432 A Longitudinal Study of Clinical Parameters and Cytokine Profiles in IBS

Abstract

Background: In western populations where there is a high prevalence of celiac disease (CD), serological and tissue markers were found to be more common in patients with irritable bowel syndrome (IBS) phenotype. While CD is believed to be uncommon in Chinese, there is a report from China suggesting that this association may also exist. Aim: To study the prevalence of celiac disease markers in patients with IBS criteria and of Chinese ethnicity from Singapore, where there has been increasing wheat consumption. Method: We explored this association in a cohort of ethnic Chinese patients with IBS by Rome III criteria, who had all undergone IgA anti-gliadin antibody (AGA) and IgA anti-endomysial antibody (EMA) serology testing and duodenal biopsies as part of their clinical workup. In addition, we recalled patients with positive serology for further test of human leukocyte antigens HLADQ2 and HLA-DQ8, which are known to be associated with celiac disease. Result: In 106 patients of Chinese ethnicity who fulfilled Rome III IBS criteria 16 (15.1%) were tested positive for AGA, and 7 (6.6%) had intra-epithelial lymphocytosis reported in duodenal biopsies. None of the patients was positive for EMA. The prevalence of intra-epithelial lymphocytosis (IEL) was numerically higher in patients with positive AGA than negative AGA serology, with 3 (18.8%) and 4 (4.4%) respectively (p=0.105). Similarly, villous atrophy was numerically more common in AGA positive than AGA negative group with 8(50%) and 30(33.3%) respectively (p=0.20). None of these patients had more than mild villous atrophy. The prevalence of Helicobacter pylori infection in AGA positive and AGA negative groups were 18.8% and 28.9% respectively (p=0.40). Nine of the 16 patients in the AGA positive group agreed to undergo HLA-DQ2/8 genotyping, and only 2 patients were positive for HLA-DQ8. These two HLA-DQ positive patients are sisters whose parents had emigrated from the northern part of China where the traditional dietary staple was wheat. Neither of them had villous atrophy, but one had IEL. The other 7 patients who were HLA-DQ2/8 genotype negative were descended from tribes in the southern part of China; one of the patients had concurrent systemic lupus erythematosus (SLE). Five of the 7 patients had villous atrophy, while two of the 7 patients had IEL. Conclusion: Our observations suggest that celiac disease could be present in some ethnic Chinese patients with IBS criteria. However there is a subset of Chinese patients with positive anti-gliadin serology who do not have the full histologic features for celiac disease and were HLA haplotype negative, suggesting that these patients could IBS associated with an immune sensitization to gluten not amounting to celiac disease.