Interleukin (IL)-18 is a pleiotropic cytokine, which may play a role in autoimmune and allergic disorders. Serum IL-18 levels were measured in 34 patients with chronic ordinary urticaria (COU) and 17 normal subjects. In vivo and in vitro assays for histamine-releasing factors, an autologous serum skin test (ASST) and a basophil histamine release assay were also performed for all patients with COU. Serum IL-18 concentration was not significantly different between patients with COU and normal subjects (mean+/-standard error of the mean 246.47+/-18.40 pg/mL vs. 213.88+/-22.24 pg/mL), and no significant difference was found between ASST-positive and ASST-negative patients. However, in ASST-positive patients, IL-18 levels paralleled clinical severity scores and showed a tendency to correlate with in vitro histamine release. The increased IL-18 levels in the ASST-positive patients with most active chronic urticaria may reflect stronger immune system activation and possibly an involvement of IL-18 as a direct histamine-releasing factor.

exercise. Only oral challenge with a wheatmeal roll followed by an additional exercise test on the bicycle ergometer produced immediate-type reactions. After 20 min, itching of the skin on the neck and back occurred, followed by generalized urticaria with swelling of the upper lip. The patient received intravenous injections of 4 mg of dimetindene maleate and 250 mg of methyl-prednisolone. This relieved the symptoms within minutes. In the literature, 163 cases of fooddependent, exercise-induced anaphylaxis are described; they have been reviewed by Steurich & Feyerabend (3). Although various foods (tomato, peanut, soybean, and seafood) have been associated with food-dependent, exercise-induced anaphylaxis, the most frequently reported cause of these reactions seems to be wheat (3). The activities required to precipitate symptoms were running, ball games, tennis, and walking. Our patient was atopic and suffered from face dermatitis and perennial rhinitis with allergy to house-dust mites. The positive skin test and the detection of speci®c IgE antibodies made it possible to demonstrate an immediate-type allergy to wheat¯our and gluten (gliadin). Recently, Palosuo et al. demonstrated by ELISA that the major allergen of wheat is gliadin (4). Only oral challenge with a wheatmeal roll followed by exercise produced immediate-type reactions such as generalized urticaria and swelling of the upper lip, and thus led to the diagnosis of food-dependent, exercise-induced anaphylaxis to wheat¯our (gliadin).

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in patients with CIU intolerance to NSAID does not depend on the mechanism of histamine release.