Differential Allergenicity and Heavy Metal Content in <scp> <i>Dactylis glomerata</i> </scp> and <scp> <i>Lolium perenne</i> </scp> 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.