电子垃圾拆解区化学污染物暴露降低儿童疫苗接种后抗体水平的机制

Exposure to chemical pollutants can cause adverse effects to children whose immune system has not been well developed. In the previous study, we found that protective antibodies levels in children from electronic waste recycling area, Guiyu, who received standard vaccine injection according to the national immunization programs, were significantly lower than the values obtained from the control area. Also, the concentrations of blood lead, cadmium, chromium, mercury, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons, polychlorinated biphenyls were higher than that of the control group. Analysis of the data showed that some chemical pollutants were negatively correlated with the level of antibodies. We speculate that exposure to chemical pollutants could reduce the children's vaccine antibody levels. The possible mechanism may be interfered from the B cell activation, CD40/40L co-stimulatory pathways, T-helper cell differentiation of the immune response and the change in certain key gene methylation status of these processes. The change in the methylation status of these key genes may be the key factor causing this low level of antibodies in the children of e-waste recycling area. The present project seeks to determine the concentration of chemical pollutants, antibodies, related immune cells and cytokines, as well as the methylation status of key genes and correlation analysis between these factors. Cross-sectional and cohort studies will be done. We seek to reveal the mechanisms of how exposure to chemical pollutants affect children antibody formation after standard vaccine injection, and provide a scientific basis for guiding child vaccination and prevention of antibody-related diseases.

化学污染物暴露会对尚未发育完善的儿童免疫系统造成毒性损害。我们前期研究发现，电子垃圾拆解区儿童按国家免疫接种程序接种一类疫苗后，体内相应抗体水平明显低于对照组，而血中的铅、镉、铬、汞、多溴联苯醚、多环芳烃、多氯联苯、全氟辛酸含量均高于对照组，分析两者数据显示某些化学污染物与抗体水平呈负相关。我们认为：化学污染物暴露会降低儿童疫苗接种后抗体水平，其机制可能是干扰免疫应答过程中B细胞激活、CD40/40L共刺激途径、Th细胞分化过程，以及改变这些过程中某些关键基因甲基化状态。这些关键基因甲基化状态的改变可能是导致儿童抗体水平低下的关键因素。本项目将通过检测儿童血中多种化学污染物的含量、一类疫苗抗体的水平、相关免疫细胞和因子及其关键基因的甲基化状态，分析这些因素之间的相关性，通过横向比较和队列研究，揭示化学污染物暴露干扰儿童接种疫苗后抗体生成的机制，为指导儿童疫苗接种和预防相关疾病提供科学依据

通过开展该项目，我们发现贵屿电子垃圾拆解区儿童①体内重金属和有机污染物水平较高，重金属以铅暴露为主，有机污染物以PBDEs、PCBs为主；②炎性细胞和炎症因子水平相对较高，处于炎症前期；③炎症介质基因甲基化水平存在差异；④七种一类疫苗抗体浓度偏低；⑤红细胞形态、红细胞比容、红细胞体积、血红蛋白合成以及红细胞补体受体1表达受到影响。儿童免疫系统发育和功能受到干扰主要与铅暴露有关。共计发表论文28篇，其中SCI论文19篇，包括J of Hazardous Material、 Human Reproduction、Environmental Pollution、Science of the Total Environment、Chemosphere等杂志，获2016 年度广东省科技进步三等奖1项。