Study of some immunological parameters in workers occupationally exposed to benzene

Objective: The aim of the study was to investigate the immunotoxicity of be nzene exposure, to establish the correlation between the exposure biomarker s and some immunological parameters, and to assess the possible influence o f confounding factors on the results of immunological assay applicable in r outine medical surveillance of benzene-exposed workers. Methods: Forty-nine female workers in the shoemaking industry who were exposed to solvent mixt ures and 27 nonexposed controls were examined. Workers were exposed to benz ene concentrations of up to 15 ppm, and to toluene of up to 50 ppm. Results : Significant differences in the levels of benzene and toluene in blood and phenols in post-shift urine between the exposed and the control group conf irmed solvent exposure. The number of B-lymphocytes (P = 0.01) was lower in the shoe workers than in the controls. Significant correlation was found b etween the level of immunoglobulin G and benzene in the work atmosphere, wh ile confounding factors had no impact on immunological values. Conclusion: According to these results, exposure to benzene concentration lower than 15 ppm can induce depression of the circulating B-lymphocyte level and theref ore this fact could be used to develop a promising method for health survei llance of benzene-exposed workers. However, considerably more effort in the research on benzene immunotoxicity, especially in the search for suitable health surveillance methods. is still required.