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Systemic immune cell response in rats after pulmonary exposure to manganese-containing particles collected from welding aerosols.

Antonini JM; Zeidler-Erdely PC; Young S-H; Roberts JR; Erdely A
J Immunotoxicol 2012 Apr-Jun; 9(2):184-192
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 (MnCl(2)). 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 MnCl(2) 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.
Welding; Welders; Welding-industry; Inhalants; Immune-system; Immune-system-disorders; Immune-reaction; Exposure-levels; Exposure-limits; Workers; Magnesium-compounds; Fumes; Laboratory-animals; Lung; Lung-disease; Lung-disorders; Lung-function; Lung-tissue; Particulates; Epidemiology; Statistical-analysis; Pulmonary-function; Pulmonary-disorders; Pulmonary-system; Author Keywords: Welding fume; immunotoxicity; manganese; blood analysis; particulate matter
James M. Antonini, PhD, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Road Mailstop 2015, Morgantown, WV 26505
7439-95-4; 7786-30-3
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Journal of Immunotoxicology
Page last reviewed: March 25, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division