Tomato allergy in children and young adults: cross-reactivity with latex and potato.

BACKGROUND: Several studies have shown that allergy to natural rubber latex is associated with cross-reactivity to certain foods such as tomato and potato. The objective was to investigate the clinical and immunologic differences between a group of patients with clinical allergy to tomato and latex and another which had only clinical allergy to tomato. We also aimed to assess, in vitro, the relationship of tomato and latex allergens, which could explain the cross-reactivity. METHODS: Forty patients with histories of adverse reactions to tomato and IgE-mediated hypersensitivity were enrolled in the study. Tomato, latex, and potato components were analyzed by SDS-PAGE immunoblotting. CAP and immunoblot inhibition were used to study allergen cross-reactivity. RESULTS: Patients from group A had a mean age of 13.2 years, and in group B the mean age was 21.7 years. In group B, 9/10 patients belonged to the latex-fruits syndrome. All patients of both groups tolerated potato. Immunoblotting patterns obtained with patients' sera from pool A showed IgE-binding bands to tomato ranging from 44 to 46 kDa and a triple band at 67 kDa. For latex, there was a strong binding at 44 kDa, and potato showed a strong band of 44 kDa and a 67-kDa triple band. In pool B, the binding to the band of 44 kDa in latex and tomato was more intense than in pool A. In pool A, immunoblot inhibition with potato allergen showed an intense inhibition of the three allergens (potato, latex, and tomato); with latex, inhibition was partial and with tomato, a complete inhibition of tomato and latex was observed, and a partial inhibition of potato. In pool B, the inhibition pattern followed a similar tendency to pool A. The CAP inhibition confirmed the high rate of cross-reactivity between tomato, potato, and latex. CONCLUSIONS: In our study, tomato, potato, and latex showed a common band of 44-46 kDa probably corresponding to patatin. This protein could be implicated in the high cross-reactivity between tomato, latex, and potato observed in the immunoblot and CAP inhibition.

Allergy to lentils in Mediterranean pediatric patients.

BACKGROUND: Peanuts and soybeans are the major legumes involved in human food allergy; however, scarce data exist on adverse reactions to other temperate legumes, such as lentils. OBJECTIVE: The purpose of this study was to identify patients who are allergic to lentils, to assess clinical features and other associated food allergies, and to characterize allergens in lentil extract. METHODS: Twenty-two children each with a history of adverse reactions to lentils were enrolled in the study. The diagnosis of lentil allergy was based on food challenges or a convincing history of anaphylaxis, with positive skin tests and/or specific serum IgE to lentils. Lentil components were characterized by SDS-PAGE immunoblotting. RESULTS: Twenty of 22 subjects had symptomatic allergy to lentils at the diagnostic time. The most frequent symptoms were oropharyngeal symptoms (40%) and acute urticaria (30%); 3 patients also reported symptoms when they were exposed to steam from cooked lentils. In 18 patients, symptoms after lentil ingestion started under 4 years of age (median, 2.7 years). Nine patients had allergic reactions to other legumes: chick peas (6 patients), peas (2 patients), and green beans (1 patient). Immunoblotting patterns obtained with patients' sera showed IgE-binding bands ranging from 14 to 84 kd. Five sera recognized 9 or more IgE-binding bands, and more than 50% of patients who were tested have specific IgE antibodies to 7 components in lentil extract. CONCLUSION: Allergic reactions to lentils started early in life, usually below 4 years of age; oropharyngeal symptoms and acute urticaria were the most common symptoms through ingestion, and symptomatic reactivity to chick peas is frequently associated.

Atopy and bronchial hyperresponsiveness in pure extrinsic childhood asthma.

Nonspecific bronchial hyperresponsiveness and atopy are considered risk factors in the development of asthma. Bronchial responsiveness to allergens could be the most important factor in extrinsic asthma. The trial was designed to investigate the role of specific and nonspecific bronchial responsiveness and atopy in a pure model of extrinsic asthma in children. One hundred and thirty-seven patients with pollen allergy were evaluated. Twenty children with allergy to grass pollen (Lolium perenne) alone, with symptoms only in the grass pollen season, were selected. Their score of symptoms, airway responsiveness to methacholine in and out of season, airway responsiveness to Lolium perenne out of season, and total and specific IgE were assessed. Twelve were male and eight female. Mild asthma was observed in 14, and moderate asthma in six. Age of onset of symptoms ranged from three to 13 years of age. Significant seasonal increase in airway responsiveness to methacholine was found (p = 0.002). Specific bronchial challenge test was positive in all patients. Lolium pernne PD20 ranged from 2.3 to 155.5 inhalation units. An inverse association between age of onset of symptoms and severity of asthma was shown (p = 0.001). Increase in nonspecific bronchial responsiveness was related to the appearance of symptoms during the spring, but it showed no relationship to the severity of symptoms. Severity of asthma during the spring correlated with the intensity of allergen airway responsiveness (p = 0.02). Levels of total and specific IgE were not related to the degree of specific or nonspecific airway responsiveness. Severity of extrinsic childhood asthma is determined by bronchial response to allergens. Bronchial hyperresponsiveness to methacholine during the spring can be the consequence of environmental exposure to allergens. The intensity of airway responsiveness to methacholine has no predictive value in the severity of pure extrinsic childhood asthma.