Abstract
Background: Some foods can exacerbate the symptoms of irritable bowel syndrome (IBS), although the associations between the pathophysiology of IBS and IgG food antibodies levels are not well known. We examined IgG antibodies elicited in response to food and celiac disease in diarrhea-predominant IBS (IBS-D).
Methods: Twenty patients with IBS-D and 20 healthy controls (HC), were enrolled. Serum immunoglobulin (Ig) G antibodies to 88 dietary items were measured and scored in accordance with the rate of antibody positivity. Serum tissue transglutaminase-IgA (tTG-IgA) and IgA endomysial antibody (EMA) were measured as markers of celiac disease. Serum IgE antibodies were also measured.
Results: For the 88-item food-related IgG scores there was no significant difference in the number of dietary items with a ≥ 0.5 IgG score between the IBS and HC groups. Total IgG scores between groups were not significantly different. Scores for wheat, rye, and oats were not significantly different for the IBS versus the HC group. IgG scores for apples were significantly higher in the IBS versus the HC group. Serum tTG-IgA and EMA titers were negative in both groups and not significantly different between groups. Serum IgE was also not significantly different between groups. One patient with high titers for wheat, rye, and oats had duodenal mucosa histology classified as Marsh 1 and was negative for human leukocyte antigen DQ haplotypes HLA-DQ2/HLA-DQ8.
Conclusions: We investigated IgG antibodies to food, tTG-IgA, and EMA in patients with IBS-D in whom IgG levels are likely influenced by dietary habits.