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

Nuñez-Borque E1, Betancor D2, Fernández-Bravo S1, Gómez-Cardeñosa A2, Esteban V1,3, Garrido-Arandia M3,4, de las Heras M2, Pastor-Vargas C1,3,5*, Cuesta-Herranz J2,3*

1Department of Immunology, Instituto de Investigación Sanitaria Hospital Universitario Fundación Jiménez Díaz (IIS-FJD, UAM), Madrid, Spain
2Department of Allergy. Hospital Universitario Fundación Jiménez Díaz. Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD, UAM), Madrid, Spain
3RETIC ARADyAL, Instituto de Salud Carlos III, Spain
4Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Madrid, Spain
5Department of Biochemistry and Molecular Biology, Universidad Complutense de Madrid, Madrid, Spain
*Both authors contributed equally

J Investig Allergol Clin Immunol 2022; Vol. 32(5)
doi: 10.18176/jiaci.0702

Background: Platanus acerifolia is a deciduous tree of the Platanaceae family. Sensitisation to this plant varies with geography. Madrid, located in central Spain, has one of the highest pollen concentration levels of this tree of the Iberian Peninsula.
Objectives: We evaluated both the clinical characteristics and molecular sensitisation pattern of patients with allergy to the London Plane tree in the region of Madrid.
Patients and Methods: Thirty-eight patients allergic to London Plane tree pollen were selected according to clinical symptoms, positive skin prick test, and/or specific IgE. Serum was collected and allergen components were evaluated by immunodetection techniques as well as ImmunoCAP. IgE-binding proteins detected were identified and characterised by 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, corresponding 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. Allergen characterisation identified the 27-kDa protein to be glutathione-S-transferase.
Conclusions: The molecular profile of patients sensitised to London Plane tree pollen differs from that reported in studies from other locations. Our population showed a higher prevalence of Pla a 2 compared to Pla a 1 and Pla a 3. In addition, the minor allergen previously referred to as Pla a 4 was characterised as glutathione-S-transferase.

Key words: Plane tree, Platanus acerifolia, Pollen allergy, Allergen, Pla a 2