Toxicology 135 (1999) 43 – 47 Investigation of some immunological functions in a group of asphalt workers exposed to polycyclic aromatic hydrocarbons A. Karakaya a, *, B. Yu ¨ cesoy a , A. Turhan b , O. Erdem c , S. Burgaz c , A.E. Karakaya c a Department of Toxicology, Faculty of Pharmacy, Ankara Uniersity, 06100, Tandoðan, Ankara, Turkey b Department of Immunology, Faculty of Medicine, Gazi Uniersity, 06500, Bes ¸eler,Ankara, Turkey c Department of Toxicology, Faculty of Pharmacy, Gazi Uniersity, 06330, Hipodrom, Ankara, Turkey Received 10 August 1998; accepted 21 March 1999 Abstract To investigate the effects of polycyclic aromatic hydrocarbons (PAHs) on the human immune system, analyses were performed on T-cell subsets (CD4 + , CD8 + ), B-cells (CD19 + ), serum immunoglobulin levels (IgG, IgM, IgA) and white blood cell percentages of 16 male workers who were employed in road paving operations and compared to 12 unexposed male controls. PAH exposure was assessed using urinary 1-hydroxy-pyrene (1-OHP) levels and was found to be significantly higher in workers than in the controls. While the CD4 + cell percentage and the CD4 + /CD8 + ratio were significantly higher in the PAH-exposed group, the percentages of CD8 + and CD19 + cells were unchanged. There was also a significant enhancement in serum IgG levels and the percentage of monocytes in the workers compared to the control group. These data suggest that chronic exposure to PAHs may affect some immune functions in humans. © 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: PAH; Immune system; Occupational exposure organic materials such as coke, coal tar and pitch, asphalt and oil. These agents are well known human carcinogens. Likewise, their effects on the immune system of animals and humans has be- come more understood. It was suggested that their immunotoxicity contributes to their carcino- genic potential (Luster et al., 1992; Luster and Rosenthal, 1993). They cause suppression of hu- 1. Introduction Polycyclic aromatic hydrocarbons (PAHs) are formed by pyrolysis or incomplete combustion of * Corresponding author. Tel.: +90-312-2126805; fax: +90- 312-2131081. E-mail address: karakaya@io.pharmacy.ankara.edu.tr (A. Karakaya) 0300-483X/99/$ - see front matter © 1999 Elsevier Science Ireland Ltd. All rights reserved. PII:S0300-483X(99)00048-7