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.

Effect of O3 and NO2 atmospheric pollutants on Platanus x acerifolia pollen: Immunochemical and spectroscopic analysis.

In the present study, the effects of two important oxidizing atmospheric pollutants (O3 and NO2) on the allergenic properties and chemical composition of Platanus x acerifolia pollen were studied. Pollen samples were subjected to O3 and/or NO2 under in vitro conditions for 6h at atmospheric concentration levels (O3: 0.061ppm; NO2: 0.025ppm and the mixture of O3 and NO2: 0.060 and 0.031ppm respectively). Immunoblotting (using Pla a 1 and Pla a 2 antibodies), infrared and X-ray photoelectron spectroscopy techniques were used. Immunochemical analysis showed that pollen allergenicity changes were different according to the pollutant tested (gas or mixture of gasses) and that the same pollutant gas may interact in a different manner with each specific allergen. The spectroscopy results showed modifications in the FTIR spectral features of bands assigned to proteins, lipids, and polysaccharides of the pollen exposed to the pollutants, as well as in the XPS spectra high-resolution components C 1s, N 1s, and O 1s. This indicates that while airborne, the pollen wall suffers further modifications of its components induced by air pollution, which can compromise the pollen function.