Objective: The aim of the study was to investigate the immunotoxicity of benzene exposure, to establish the correlation between the exposure biomarkers and some immunological parameters, and to assess the possible influence of confounding factors on the results of immunological assay applicable in routine medical surveillance of benzene-exposed workers.
Methods: Forty-nine female workers in the shoemaking industry who were exposed to solvent mixtures and 27 nonexposed controls were examined. Workers were exposed to benzene 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 confirmed solvent exposure. The number of B-lymphocytes (P = 0.01) was lower in the shoe workers than in the controls. Significant correlation was found between the level of immunoglobulin G and benzene in the work atmosphere, while 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 therefore this fact could be used to develop a promising method for health surveillance 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.