Differential Allergenicity and Heavy Metal Content in Dactylis glomerata and Lolium perenne Pollen Across Contrasting Environments

Air pollution and heavy metals can alter the composition and allergenicity of grass pollen, yet field-based evidence remains scarce. This study investigates Dactylis glomerata and Lolium perenne pollen, and how urban/industrial conditions influence sub-pollen particle (SPP) release, chemical composition, and IgE reactivity-extending prior work on Phleum pratense pollen. Pollen was collected near Kruševac (central Serbia) from two sites ~10 km apart: a rural area (D1/L1) and a location adjacent to a regional road and chemical plant (D2/L2). SPP release during osmolysis was quantified by light microscopy; protein profiles were assessed via 1D SDS-PAGE; elemental content analyzed by ICP-OES/MS; PAHs by GC-MS; and IgE binding measured by ELISA, using sera from a previous study (16 grass pollen-allergic patients). Urban samples released significantly more SPP (several-fold increase) and showed elevated protein expression with altered protein/allergen patterns. D2 pollen contained ~10× more As and ~5× more Cd than D1; L. perenne from L2 had elevated Ni (~15 μg/g) and 5× more indium than L1. Acenaphthylene was detected only in polluted samples, while anthracene was present only in D2 pollen. Notably, 56% of sera showed stronger IgE binding to contaminated D. glomerata, suggesting heightened allergic potential at equal pollen loads. These findings support a link between air pollution and increased respiratory allergy risk, highlighting pollen's potential as a bioindicator of environmental contamination.