Intestinal B cell-activating factor: an indicator of non-IgE-mediated hypersensitivity reactions to food?

Background Medically confirmed hypersensitivity reactions to food are usually IgE-mediated. Non-IgE-mediated reactions are not only seldom recognized but also more difficult to diagnose. Aim To examine B cell-activating factor (BAFF) in serum and gut lavage fluid of patients with self-reported food hypersensitivity, and to study its relationship to atopic disease. Methods Gut lavage fluid was obtained from 60 and serum from another 17 patients with self-reported food hypersensitivity. Twenty healthy volunteers served as controls, gut lavage fluid was obtained in all, serum from 11 of 20. The patients were divided into atopic and non-atopic subgroups. BAFF was measured by ELISA in both serum and gut lavage fluid. Results B cell-activating factor levels in serum and gut lavage fluid were significantly higher in patients than in controls (P < 0.03 and P < 0.002 respectively). Non-atopic patients had significantly higher levels of BAFF in serum than both atopic patients (P < 0.05) and controls (P < 0.05). There was no significant correlation between serum levels of BAFF and IgE. Conclusions The results suggest that BAFF might be a new mediating mechanism in food hypersensitivity reactions. Significantly higher levels in non-atopic compared with atopic patients, and no correlation between BAFF and IgE, suggest that BAFF might be involved particularly in non-IgE-mediated reactions. Aliment Pharmacol Ther 2010; 32: 66-73