A Cross-Sectional Study on Immune-Inflammatory Responses: Exposure to Polycyclic Aromatic Hydrocarbons Alters Pteridine Metabolism and Activates the Kynurenine Pathway.

Authors

Terken Baydar, Saziye Sezin Palabiyik-Yucelik, Gözde Girgin, Hande Sipahi, Engin Tutkun, Omer Hinc Yilmaz

Published in

Chemical research in toxicology. Jul 06, 2026. Epub Jul 06, 2026.

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants generated from the incomplete combustion of organic materials and represent an important source of occupational and environmental exposure. Aside from their carcinogenic properties, PAHs are known to exert immunomodulatory and proinflammatory effects. Immune activation is closely associated with alterations in pteridine metabolism and activation of the kynurenine pathway; however, evidence linking PAH exposure to these immune-inflammatory pathways in humans remains limited. This study aimed to investigate the systemic biological effects of occupational exposure to PAHs from asphalt fumes in road construction workers, with a particular focus on alterations in pteridine metabolism and activation of the kynurenine pathway, using a combined panel of exposure and mechanistic biomarkers. Routine clinical parameters remained within normal ranges while urinary 1-hydroxypyrene, a well-established biomarker of internal PAH exposure, was significantly elevated, confirming substantial PAH exposure. Key findings revealed profound alterations in two critical metabolic pathways: (i) Pteridine metabolism was shifted, with increased neopterin and decreased biopterin levels, indicating activation of cell-mediated immunity and reduced cofactor availability; (ii) the kynurenine pathway was concurrently activated, as reflected by elevated kynurenine, reduced tryptophan, and increased estimated indoleamine 2,3-dioxygenase activity. These findings indicate that low-level but chronic PAH exposure induces sustained Th1-type immune activation and metabolic disturbances in the absence of overt clinical pathology, representing a state of subclinical biological adaptation.

PMID:
42406640
Bibliographic data and abstract were imported from PubMed on 07 Jul 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.