Increased leukotriene production by food additives in patients with atopic dermatitis and proven food intolerance

Background Recently, we identified a subgroup of patients with atopic dermatitis (AD) with a clinical relevant food intolerance proven by double blind placebo controlled challenge. In search of possible pathomechanisms involved in this food intolerance, which leads to aggravation of the disease, the aim of the present study was to determine sulfidoleukotriene production in these patients using isolated leucocytes from the peripheral blood after stimulation with different food additives. Methods Leukotriene production of peripheral leucocytes was detected by incubation of isolated cells with the food additives at different concentrations ranging from 0.2 to 200 mug/mL after pre-stimulation with IL-3. Ten non-atopic donors (A), nine AD patients of the diet responder group with negative oral provocation test against food additives (B) and nine patients of the responder group with positive reactions after the oral provocation test (C) were investigated. Results In the non-atopic group (A), no increased sulfidoleukotriene (sLT) release was observed for all food additives tested. In group B, increased sLT production was determined using tartrazine in one patient (1/9) and using nitrite in two patients (2/9), whereas sLT production remained below the cut-off range in all patients of group B (9/9) using benzoate, metabisulfite and salicylate. By contrast, in group C increased sLT production was observed with food colour mix in 1/9, with tartrazine in 3/9, with benzoate in 4/9, with nitrite in 5/9, with salicylate in 2/9 and with metabisulfite in 1/9. However, no increased sLT concentration was determined in the presence of the tested food additives in two patients of group C. Conclusions Increased sLT production by peripheral leucocytes in the presence of single food additives was observed in the majority of patients with a proven food intolerance towards food additives proven by double-blind-placebo-controlled challenges. These food additives were particulary tartrazine, benzoate and nitrite. These findings indicate that single food additives as aggravating factors in AD patients may trigger the disease through increased sLT production as a pathophysiological mechanism.