慢性铅接触者胸腺输出近期功能的研究

目的分析铅接触者外周血T细胞受体删除DNA环(TRECs)的含量,了解其初始T细胞含量和胸腺近期输出功能,从而研究其免疫功能的情况。方法采用实时定量PCR方法检测10例铅接触者外周血TRECs含量,与11例非铅接触者进行比较;采用双变量相关分析法和偏相关分析法分析铅接触组TRECs水平与年龄、工龄、血铅、尿铅、血锌原卟啉(ZPP)和尿δ-氨基-γ-酮戊酸(δ-ALA)浓度的关系。结果10例铅接触者TRECs水平[(2.44±1.87)/1000]明显低于非铅接触者[(5.60±3.96) /1000];TRECs水平与尿δ-ALA浓度呈负相关,有统计学意义(r=-0.754,P<0.05),但控制血铅或尿铅因素后,TRECs水平与尿δ-ALA浓度则无相关性(P>0.05)。结论铅对胸腺输出功能可能造成一定程度的损伤,且TRECs与血铅和尿铅存在相关性,提示低水平的铅接触早已损伤人体的免疫功能。

Effects of lead exposure on thymic output naive T cells function

OBJECTIVE: To investigate the levels of T cell receptor rearrangement excision DNA circles (TRECs) within peripheral blood from workers exposed to lead, and thereby to evaluate the number of naive T cells and recent thymic output function. METHODS: Quantitative detection of TRECs in peripheral blood mononuclear cells (PBMNC) from 10 cases of workers exposed to lead was performed by real time PCR analysis. 11 workers without exposure to lead served as unexposed controls. In addition, the relationship between TRECs, age, length of service, blood lead, urea lead, blood ZPP and urea delta-ALA was investigated. RESULTS: The mean value of TRECs in workers exposed to lead was (2.44 +/- 1.87)/1000 PBMC, significantly under (5.60 +/- 3.96)/1000 PBMC in unexposed controls. A significant negative correlation was found between the TRECs and urea-ALA. But there was no significant correlation between them after controlling for blood lead, urea lead. CONCLUSION: Lead exposure may damage thymic output naive T cells function. Furthermore, low-level exposure to lead may damage immune system and earlier than expected.