CD3-Zeta Gene Expression in Workers Benzene-Exposed and Benzene- Poisoned Workers

Abstract

Benzene is an industrial chemical and component of cigarette smoke, gasoline, and automobile emissions. Benzene's toxic effects on the blood and bone marrow can induce aplastic anemia and leukemia. Benzene is known to be highly toxic to a variety of cell types including lymphocytes. Our previous study showed that skewed distribution and clonal expansion of TCR Vα subfamily T cells had been found in benzene-exposed workers, indicating that the disorder of T cell immune function might relate to benzene-exposed. The TCR expressed on the surface of T cells is associated with an invariant structure-CD3 and composed the TCR/CD3 complex. The CD3ζ chain plays an important role in the complex which involved in signal transduction. Little is known about the feature of CD3 ζ chain expression in benzene-exposed workers. To further identify the expression level of CD3 ζ gene in benzene-exposed workers, real-time PCR with SYBR Green±technique was used for detecting CD3 ζ gene expression level in peripheral blood mononuclear cells from 29 benzene-exposed workers, 42 benzene-poisoned workers and 20 normal individuals. β2- microglobulin gene (β2M) was used as an endogenous reference. Relative changes in CD3 ζ gene expression level was used by the 2−ΔCt×100% method (ΔCt=Ct(ζ) −Ct(β2M) ). CD3ζ gene could be detected in all of normal individuals, however, only 21 out of 29 benzeneexposed workers could be detected the CD3ζ gene with a mean expression level of 15.0 ±24.9, and in 33 of all 45 benzene-poisoned workers with mean value of 19.8 ±29.7. The detectable CD3 ζ gene expression level in both benzene-exposed and benzene-poisoned groups increased significantly compared with that in normal individuals (3.00±2.11, P< 0.05). This is, to our knowledge, the first description of the effect of benzene-exposed on the expression of the CD3 ζ gene. The abnormality expression of CD3 ζ gene might lead to immune dysfunction in benzene-exposed and benzene-poisoned workers. In addition, CD3ζ gene could not be detected in a part of samples, whether the absence of CD3ζ gene might related to dysfunction of T cells in workers with benzene-exposed and benzenepoisoned, it remains an open question.