Polycyclic aromatic hydrocarbons (PAHs), ubiquitous pollutants produced by incomplete combustion and electronic waste (e-waste) recycling, are increasingly recognized as contributors to immune dysfunction and chronic inflammation. To elucidate their biological impacts, we conducted a series of studies involving 239–248 preschool children from e-waste-exposed and reference areas. Urinary monohydroxylated PAHs (OH-PAHs) were measured as exposure biomarkers, along with multiple indicators of systemic, mucosal, and lipid-mediated inflammation. Children living in e-waste areas exhibited significantly higher urinary OH-PAH concentrations, especially 1-hydroxynaphthalene and 2-hydroxynaphthalene, associated with environmental and behavioral factors. PAH exposure was linked to reduced lymphocyte ratio, altered platelet morphology (lower mean platelet volume, platelet distribution width, and large-cell ratio), and increased pro-inflammatory cytokines including IL-1β, IL-6, IL-10, TNF-α, and IFN-γ. Expression of aryl hydrocarbon receptor (AhR) and NLRP3 inflammasome was elevated and mediated the associations between PAHs and cytokines implicated in cytokine storm–like responses. Intestinal immune alterations were also observed, with increased sialyl Lewis A, elevated secretory IgA, reduced CD4⁺ T-cell proportion, and higher diarrhea risk. Lipidomic profiling revealed disrupted oxylipin metabolism characterized by increased pro-inflammatory 9,10-DiHOME and decreased anti-inflammatory epoxides such as EETs and EpDPEs. Mediation analyses identified platelet indices, AhR, NLRP3, and oxylipins as critical intermediaries linking PAH exposure to systemic inflammation. These findings demonstrate that chronic low-level PAH exposure from e-waste environments induces multi-level immune dysregulation and persistent inflammation in children. Platelet parameters, AhR/NLRP3 pathways, intestinal immune markers, and oxylipin signatures represent potential biomarkers for early detection and mechanistic insight into PAH-induced chronic inflammation.

Polycyclic aromatic hydrocarbons,Chronic inflammation,Platelet indices,Oxylipins,Intestinal immunity