Effects of occupational trichloroethylene exposure on cytokine levels in workers

Objective: We sought to investigate trichloroethylene-induced alterations of the immune system in humans. Methods: The levels of interleukin-2, interleukin-4, and interferon-gamma in sera obtained from workers exposed to trichloroethylene were determined and compared with those of internal and external control subjects. Results: In workers with a mean urinary trichloroacetic acid concentration of 13.3 +/- 5.9 mg/g creatinine, exposed to a mean environmental trichloroethylene level of 35 +/- 14 mg/m(3), we observed a significant increase in sera interleukin-2 and interferon-gamma levels and a reduction in interleukin-4 concentrations compared with those of workers from the internal and external control groups. Conclusions: This study provides the first report on quantitative immune changes induced by occupational exposure to low levels of trichloroethylene and strongly suggests that exposure to this substance alters immunohomeostasis in humans with possible effects on health.