Micro- and nanoplastic exposure, immune cell activation, and lung function in young adults.

Rationale: Micro- and nanoplastics, an emerging public health concern, enter the human body through inhalation and ingestion. The potential for this exposure to induce a pro-inflammatory immune response or impair lung function remains unknown. Objectives: This study aimed to estimate exposure to micro- and nanoplastics in young adults and investigate associations with immune activation and lung function. Methods: We performed a cross-sectional study among 100 participants of the Dutch PIAMA (Prevention and Incidence of Asthma and Mite Allergy) cohort during the 25-year follow-up. Micro- and nanoplastic concentrations in blood were quantified with pyrolysis gas chromatography mass spectrometry. Innate immune cell activation was assessed with flow cytometry by measuring CD11b, CD62L, and CD10 expresssion on neutrophils as well as CD11b expression on monocytes and eosinophils. Lung function was measured by spirometry. Linear regression analysis was used to assess associations of micro- and nanoplastic exposure with selected immune markers and lung function parameters. Measurements and main results: Micro- and nanoplastics were detected in all samples with a median total concentration of 427.5 ng/mL. Higher total micro- and nanoplastic concentrations were associated with higher expression of neutrophil, eosinophil, and monocyte CD11b, and neutrophil CD10. Higher polyvinyl chloride concentrations were associated with higher expression of eosinophil CD11b. No associations were found between micro- and nanoplastic exposure and lung function. Conclusions: These findings suggest that micro- and nanoplastics may be associated with health perturbations in young adults. Further research is warranted to confirm these observations in larger, more diverse populations. Supplementary Information: The online version contains supplementary material available at 10.1186/s43591-026-00189-2.