Year-to-year variation of the elemental and allergenic contents of Ailanthus altissima pollen grains: an allergomic study.

The Ailanthus altissima pollen (AAP) has been reported as an emerging aeroallergen worldwide. This paper aims at examining the allergen pattern and the elemental composition of A. altissima pollen collected during two consecutive seasons (2014 and 2015). A gel-based allergomic study and SEM coupled to energy-dispersive X-ray (EDX) analysis have been carried out in order to evaluate the allergenic and elemental composition of AAP in two consecutive years. The IgE reactive patterns of 2014 and 2015 AAP PBS extracts were compared using the serum of a 31-year-old woman suffering from severe pollinosis symptoms to AAP. The EDX analysis revealed an important year-to-year variation in the ratios of some polluting elements such as nickel, sulfur, aluminum, lead, and copper. Gel alignments and comparative immunoproteomic analyses showed differential protein expression and IgE reactive patterns between AAPs collected in 2014 and 2015 pollinating seasons. From 20 distinct IgE-reactive spots detected in AAP extracts, 13 proteins showed higher expression in 2014 sample, while 7 allergen candidates exhibited an increased expression in AAP collected in 2015. Matrix-assisted laser desorption ionization-MS/MS analyses led to the identification of 13 IgE-binding proteins with confidence, all belonging to well-known allergenic protein families, i.e., enolase, calreticulin, and pectate lyase. Overall, the 2014 AAP showed higher concentrations of urban polluting elements as well as an increased expression of allergenic pectate lyase isoforms of about 52 kDa. This study demonstrates that the implementation of allergomic tools for the safety assessment of newly introduced and invasive plant species would help to the comprehensive monitoring of proteomic and transcriptomic alterations involving environmental allergens.