Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
J Immunotoxicol. 2012 Apr-Jun;9(2):184-92. doi: 10.3109/1547691X.2011.650733. Epub 2012 Feb 28.
Welding fume inhalation affects the immune system of exposed workers. Manganese (Mn) in welding fume may induce immunosuppressive effects. The goal was to determine if Mn in welding fume alters immunity by reducing the number of circulating total leukocytes and specific leukocyte sub-populations. Sprague-Dawley rats were treated by intratracheal instillation (ITI) with either a single dose (2.00 mg/rat) or repeated doses (0.125 or 2.00 mg/rat for 7 weeks) with welding fumes that contained different levels of Mn. Additional rats were treated by ITI once a week for 7 weeks with the two doses of manganese chloride (MnCl₂). Bronchoalveolar lavage was performed to assess lung inflammation. Also, whole blood was recovered, and the number of circulating total leukocytes, as well as specific lymphocyte subsets, was determined by flow cytometry. The welding fume highest in Mn content significantly increased lung inflammation, injury, and production of inflammatory cytokines and chemokines compared to all other treatment groups. In addition, the same group expressed significant decreases in the number of circulating CD4⁺ and CD8⁺ T-lymphocytes after a single exposure, and significant reductions in the number of circulating total lymphocytes, primarily CD4⁺ and CD8⁺ T-lymphocytes, after repeated exposures (compared to control values). Repeated MnCl₂ exposure led to a trend of a reduction (but not statistically significant) in circulating total lymphocytes, attributable to the changes in the CD4⁺ T-lymphocyte population levels. The welding fume with the lower concentration of Mn had no significant effect on the numbers of blood lymphocytes and lymphocyte subsets compared to control values. Evidence from this study indicates that pulmonary exposure to certain welding fumes cause decrements in systemic immune cell populations, specifically circulating T-lymphocytes, and these alterations in immune cell number are not dependent exclusively on Mn, but likely a combination of other metals present in welding fume.
焊接烟尘吸入会影响暴露于其中的工人的免疫系统。焊接烟尘中的锰（Mn）可能会引起免疫抑制作用。本研究的目的是确定焊接烟尘中的 Mn 是否通过减少循环总白细胞和特定白细胞亚群的数量来改变免疫。通过气管内滴注（ITI）将含有不同水平 Mn 的焊接烟尘单次（2.00mg/大鼠）或重复（7 周内 0.125 或 2.00mg/大鼠）给予 Sprague-Dawley 大鼠。另外，一些大鼠每周通过 ITI 接受 7 周的两种剂量的氯化锰（MnCl₂）治疗。通过支气管肺泡灌洗（BAL）评估肺炎症。还回收全血，并通过流式细胞术确定循环总白细胞数量以及特定淋巴细胞亚群的数量。Mn 含量最高的焊接烟尘与所有其他治疗组相比，显著增加了肺炎症、损伤以及炎性细胞因子和趋化因子的产生。此外，同一组在单次暴露后循环 CD4⁺和 CD8⁺T 淋巴细胞数量显著减少，并且在重复暴露后（与对照组相比）循环总淋巴细胞数量显著减少，主要是 CD4⁺和 CD8⁺T 淋巴细胞数量减少。重复的 MnCl₂暴露导致循环总淋巴细胞数量减少的趋势（但无统计学意义），这归因于 CD4⁺T 淋巴细胞群体水平的变化。与对照组相比，Mn 浓度较低的焊接烟尘对血液淋巴细胞和淋巴细胞亚群的数量没有显著影响。本研究的证据表明，肺部暴露于某些焊接烟尘会导致全身免疫细胞群体，特别是循环 T 淋巴细胞的减少，而这些免疫细胞数量的改变不仅依赖于 Mn，还可能是焊接烟尘中存在的其他金属的组合。
