Lead poisoning influences TCR-related gene expression patterns in peripheral blood T-lymphocytes of exposed workers.

Previous studies have shown that occupational lead (Pb) exposure might influence human T-lymphocyte function, including such as changes in T-cell receptor (TCR) V beta and V gamma repertoire and in expression of the TCR zeta gene. Thus, the study here further investigated expression of TCR zeta-related factors and the F(c epsilon)Rl gamma gene (whose product has a functional role complementary to the TCR zeta chain) and the Elf-1 gene whose product is involved in regulation of TCR expression. Quantitative real-time RT-PCR was used to measure expression of TCR zeta, F(c epsilon)Rl gamma, and Elf-1 genes in peripheral blood mononuclear cells (PBMC) isolated from 17 Pb-exposed workers. Samples were collected before and after the workers had undergone chelation therapy regimens. Twenty-three healthy individuals served as controls. The results showed that TCR zeta, F(c epsilon)Rl gamma, and Elf-1 gene expression in Pb-exposed workers before chelation therapy was significantly lower than in PBMC from healthy individuals. After chelation therapy, expression of TCR zeta appeared to trend toward normal levels; in comparison, lower expressions of Fc epsilon RI gamma and Elf-1 persisted. In conclusion, the previously-documented impairment of T-lymphocyte functions and T-lymphocyte-mediated immune responses seen previously in response to occupational Pb exposure might be attributable, in part, to effects on TCR signaling pathways - including those related to TCR zeta and F(c epsilon)Rl gamma - and to any down-regulation of membrane TCR zeta expression/activity that might be associated with Pb-induced effects on Elf-1 expression.