Fenga Concettina, Gangemi Silvia, Di Salvatore Valentina, Falzone Luca, Libra Massimo
Department of Biomedical, Odontoiatric, Morphological and Functional Images, Section of Occupational Medicine, 'Policlinico G. Martino' Hospital, University of Messina, I-98125 Messina, Italy.
Department of Biomedical and Biotechnological Sciences, Laboratory of Translational Oncology and Functional Genomics, Section of General and Clinical Pathology and Oncology, University of Catania, I-95124 Catania, Italy.
Mol Med Rep. 2017 May;15(5):3355-3360. doi: 10.3892/mmr.2017.6381. Epub 2017 Mar 24.
It is well-known that occupational and environmental exposure to several factors, including benzene, heavy metals, chemicals and mineral fibers, is associated with the risk of developing a great number of diseases. Numerous studies have been carried out in order to investigate the mechanisms of toxicity of these substances, with particular regard to the possible toxic effects on the immune system. However, little is known about the influence of heavy metals, such as lead, on the immune system in human populations. Lead is a heavy metal still used in many industrial activities. Human exposure to lead can induce various biological effects depending upon the level and duration of exposure, such as toxic effects on haematological, cardiovascular, nervous and reproductive systems. Several studies demonstrated that exposure to lead is associated to toxic effects also on the immune system, thus increasing the incidence of allergy, infectious disease, autoimmunity or cancer. However, the effects of lead exposure on the human immune system are not conclusive, mostly in occupationally exposed subjects; nevertheless some immunotoxic abnormalities induced by lead have been suggested. In particular, in vivo, in vitro and ex vivo lead is able to improve T helper 2 (Th2) cell development affecting Th1 cell proliferation. Further studies are required to better understand the mechanisms of lead immunotoxicity and the ability of lead to affect preferentially one type of immune response.
众所周知，职业性和环境性接触多种因素，包括苯、重金属、化学物质和矿物纤维，与罹患大量疾病的风险相关。为了研究这些物质的毒性机制，尤其是它们对免疫系统可能产生的毒性作用，已经开展了大量研究。然而，对于铅等重金属对人群免疫系统的影响却知之甚少。铅是一种仍在许多工业活动中使用的重金属。人体接触铅会根据接触水平和持续时间引发各种生物学效应，例如对血液、心血管、神经和生殖系统产生毒性作用。多项研究表明，接触铅还会对免疫系统产生毒性作用，从而增加过敏、传染病、自身免疫性疾病或癌症的发病率。然而，铅暴露对人体免疫系统的影响尚无定论，在职业暴露人群中尤其如此；不过，已经有人提出铅会诱发一些免疫毒性异常。特别是，在体内、体外和离体实验中，铅能够通过影响辅助性T细胞1（Th1）增殖来促进辅助性T细胞2（Th2）的发育。需要进一步开展研究，以更好地理解铅免疫毒性的机制以及铅优先影响某一类型免疫反应的能力。
