Allergen Profile of London Plane Tree Pollen: Clinical and Molecular Pattern in Central Spain.

BACKGROUND AND OBJECTIVES: Platanus acerifolia (London plane tree) is a deciduous tree of the Platanaceae family. Sensitization to this plant varies with geography. Madrid, located in central Spain, has one of the highest London plane tree pollen concentration levels on the Iberian Peninsula. We evaluated both the clinical characteristics and the molecular sensitization pattern of patients with allergy to London plane tree pollen in the region of Madrid. METHODS: Thirty-eight patients allergic to London plane tree pollen were selected according to their clinical symptoms and positive results in skin prick testing and/or specific IgE determination. Serum was collected, and allergen components were evaluated using immunodetection techniques as well as ImmunoCAP. The IgE-binding proteins detected were identified and characterized using mass spectrometry. RESULTS: Analysis of serum samples from allergic patients revealed 9 IgE-binding bands in London plane tree pollen extract. Among these, the 45-kDa protein, which corresponded to Pla a 2, was detected in 76.3% of patients. However, the 18-kDa (Pla a 1) and 9-kDa (Pla a 3) bands were detected in 44.7% and 23.7% of sera, respectively. These results were confirmed using purified proteins. Characterization of the allergen revealed the 27-kDa protein to be glutathione-S-transferase. CONCLUSIONS: The molecular profile of patients sensitized to London plane tree pollen differs from that reported in studies from other locations. In the population we studied, the prevalence of Pla a 2 was higher than that of Pla a 1 and Pla a 3. In addition, the minor allergen previously referred to as Pla a 4 was characterized as glutathione-S-transferase.

Lettuce Allergy Is a Lipid Transfer Syndrome-Related Food Allergy With a High Risk of Severe Reactions.

BACKGROUND AND OBJECTIVE: Lipid transfer protein (LTP) sensitization is the most common cause of food allergy in the Mediterranean area, with peach allergy acting as the primary sensitizer in most cases. Lettuce has been described as a common offending food in patients with LTP syndrome. The aim of the study was to investigate the frequency and clinical expression of LTP syndrome in a sample of lettuceallergic patients. METHODS: We determined specific IgE to Pru p 3 and lettuce in a sample of 30 patients with a diagnosis of lettuce allergy. Symptoms elicited by other LTP-containing plant-derived foods and the presence of cofactors were assessed. RESULTS: The clinical symptoms of lettuce allergy were frequently severe, with 18 of the 30 patients experiencing anaphylaxis. All the patients had allergic reactions to other plant foods. Cofactors were involved in the clinical reactions of 13 of the 30 patients. Sensitization to pollens was found in 90% of patients. CONCLUSIONS: Lettuce allergy is found not as an isolated condition but in the context of LTP syndrome and it is characterized by severe reactions and frequent cofactor association.

Sensitive detection of major food allergens in breast milk: first gateway for allergenic contact during breastfeeding.

Food allergy is recognized as a major public health issue, especially in early childhood. It has been hypothesized that early sensitization to food allergens maybe due to their ingestion as components dissolved in the milk during the breastfeeding, explaining reaction to a food, which has never been taken before. Thus, the aim of this work has been to detect the presence of the food allergens in breast milk by microarray technology. We produced a homemade microarray with antibodies produced against major food allergens. The antibody microarray was incubated with breast milk from 14 women collected from Fundación Jiménez Díaz Hospital. In this way, we demonstrated the presence of major foods allergens in breast milk. The analysis of allergens presented in breast milk could be a useful tool in allergy prevention and could provide us a key data on the role of this feeding in tolerance induction or sensitization in children.

Molecular characterization of contact urticaria in patients with melon allergy.

BACKGROUND: The relevance of contact allergy to plant-related food has recently emerged. Oral allergy syndrome is one of the most characteristic symptoms of fruit allergy, although it also causes systemic reactions. Plant-food allergy is increasing at the same time as pollen allergy, and fruit-induced allergic contact urticaria could be rising as well. OBJECTIVES: The present study was carried out in order to investigate whether one particular primary melon-peel allergen is responsible for contact urticaria. METHODS: Fourteen patients presenting with contact urticaria after touching melon peel were evaluated. A melon-peel extract was prepared and analysed by immunoblotting using the patients' sera. Molecular characterization of IgE-binding bands was performed using mass spectrometry. Melon-peel lipid transfer protein (LTP) was purified. Inhibition studies and contact challenge with the protein were performed to confirm IgE reactivity to the purified allergen. RESULTS: An IgE-binding band of ~8-9 kDa was observed in an immunoblotting assay with all the patients' sera and was identified as an LTP. The melon-peel LTP was purified in two chromatography steps. Inhibition studies confirmed LTP as a major allergen in patients with melon-peel contact urticaria. Contact challenge with melon-peel LTP was performed in five patients, all of whom had positive results, exhibiting itchy erythema and hives in the area of contact. CONCLUSIONS: This study confirmed our previous findings that melon-peel LTP is a major allergen and is responsible for contact allergy. This knowledge may be used to improve both diagnosis and treatment of patients allergic to melon.