Abstract
BACKGROUND/AIMS: Food interaction, including food hypersensitivity, plays a key role in the pathogenesis of irritable bowel syndrome with diarrhea (IBS-D). Since only a few studies have been reported about the relationship between food hypersensitivity and IBS-D, we elucidate the prevalence of serological food hypersensitivity in patients with IBS-D and the characteristics of gastrointestinal symptoms and serum cytokine profiles in patients with IBS-D and serological food hypersensitivity. METHODS: Immunoglobulin E (Ig E)-mediated serological food hypersensitivity and serum cytokine levels were evaluated using the multiple allergen simultaneous test evaluating food allergen-specific serum IgE and Luminex Milliplex Panel containing multiple fluorescence-labeled beads. Class 2 or above was considered as IgE-mediated food hypersensitivity positive. The gastrointestinal symptom rating scale was used to evaluate symptoms. RESULTS: We enrolled 92 subjects, including 60 with IBS-D and 32 healthy controls. The percentages of patients with IgE-mediated serological food hypersensitivity were not significantly different between the groups (controls = 28.1% and IBS-D = 33.3%). Serum IL-1β, IL-6, IL-8, macrophage inflammatory protein-1alpha, and TNF-α levels were higher in patients with IBS-D than in controls. Serum concentration of TNF-α (43.4 vs 21.8 pg/mL, P = 0.009) was higher in patients with IBS-D without IgE-mediated serological food hypersensitivity than those with food hypersensitivity. CONCLUSIONS: One-third of Japanese patients with IBS-D showed IgE-mediated serological food hypersensitivity. The serum cytokine profile differed and was characterized by lower inflammatory cytokine levels in IBS-D with IgE-mediated serological food hypersensitivity. Serological test regarding IgE-mediated food hypersensitivity can detect a certain cluster of IBS-D.