Monitoring protein expression by proteomics: Human plasma exposed to benzene

Low levels and long term exposure to benzene is associated with hematotoxicity including aplastic anemia, acute myelogenous leukemia, and lymphoma. Current biomonitoring methods such as urinary phenol, S ‐phenylmercapturic acid, and trans‐trans muconic acid were found to be unreliable as analytical methods to detect benzene exposure. Therefore, to search for a specific protein for biomonitoring benzene exposure, we investigated plasma proteins from workers ( n = 50) at a printing company who were exposed to benzene, by two‐dimensional gel electrophoresis. The protein profiles are significantly different ( p 〈 0.05) between benzene exposed and unexposed groups, as identified by matrix‐assisted laser desorption ionization/time of flight mass spectrometry and confirmed by Western blot analyses. T cell receptor β chain (TCR β), FK506‐binding protein, and matrix metalloproteinase‐13 were expressed only in benzene exposed workers. In addition, interleukin‐4 receptor α chain and T cell surface glycoprotein CD1b precursor were found to be up‐regulated in the plasma of benzene exposed workers. When we treated Jurkat cells with benzene (10 μ M –10 m M ), TCR β expression was increased in the membrane more than 6–9‐fold compared to untreated cells. In addition, the amount of TCR β released into the culture media, at benzene concentrations greater than 50 μ M , increased up to 10 m M . Therefore, TCR β levels in plasma could be used as a biomarker and a possible therapeutic target for benzene exposure.