Immunological biomarkers in salt miners exposed to salt dust, diesel exhaust and nitrogen oxides.
OBJECTIVE
Air pollutants can affect lung function and also the immune system. In a study about lung function of salt miners in relation to the complex exposure in a salt mine, we also analysed selected immunological parameters and inflammation markers in the blood of miners. Effect of salt dust, diesel exhaust, nitrogen oxides (NOx) and smoking on the biomarkers was analysed.


METHODS
Blood was drawn from 286 salt miners, and the soluble intercellular adhesion molecule-1 (s-ICAM), monocyte chemotactic protein (MCP-1) and clara cell protein (CC16) were analysed by an immunoassay, blood profile was done and lymphocyte subpopulations (CD3, CD3/CD4, CD3/CD8, CD19, NK-cells, CD3/HLA-DR) were determined by flow cytometry. Salt dust was measured by two-step gravimetry (personal sampling). Diesel exhaust was measured as elemental carbon concentration by coulometry. NOx were determined by an electrochemical cell method. Differences between non-smokers, former smokers and active smokers were analysed by analysis of variance. Linear regression analysis to describe exposure-response relationships was done with regard to confounding factors [smoking, inflammatory diseases, time of blood drawing, respiratory infection and body-mass index (BMI)].


RESULTS
Significant differences between non-smokers and active smokers were found for most of the leukocyte types (e.g. granulocytes P = 0.000, lymphocytes P = 0.002, T-cells P = 0.033) and for some soluble parameters (ICAM P = 0.000, IgM P = 0.007, IgE P = 0.035). Increasing numbers of total lymphocytes, T-cells and HLA-DR positive T-cells in relation to exposure were found by linear regression analysis (e.g. for inhalable dust:total lymphocytes P = 0.011, T-cells P = 0.061, HLA-DR positive T-cells P = 0.007). CONCLUSION. Comparison of immunological markers in non-smokers and active smokers confirms leukocytosis and inflammation following tobacco consumption. The combined exposure of salt dust, diesel exhaust and NOx seems to influence the immune system. Together, the results suggest that the analysis of leukocytes and their subsets can complete other investigations (lung function, questionnaire) to monitor exposure-response relationships in occupational studies investigating the effect of inhaled substances. Longitudinal studies will be necessary to determine the predictive value of the immunological changes.
Backé
Eva
E
Bundesanstalt für Arbeitsschutz und Arbeitsmedizin (BAuA), Nöldnerstrasse 40-42, Berlin, Germany. backe.eva-maria@baua.bund.de
Lotz
Gabriele
G
Tittelbach
Ulrike
U
Plitzko
Sabine
S
Gierke
Erhardt
E
Schneider
Wolfram Dietmar
WD
D000328:Adult; D000395:Air Pollutants, Occupational / Q000276:immunology / Q000633:toxicity*; D015415:Biomarkers / Q000097:blood; D004391:Dust / Q000276:immunology*; D006801:Humans; D008875:Middle Aged; D008906:Mining; D009589:Nitrogen Oxides / Q000276:immunology / Q000633:toxicity*; D016273:Occupational Exposure / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects / Q000276:immunology; D001335:Vehicle Emissions / Q000009:adverse effects*
D000395:Air Pollutants, Occupational; D015415:Biomarkers; D004391:Dust; D009589:Nitrogen Oxides; D001335:Vehicle Emissions