Immunological biomarkers in salt miners exposed to salt dust, diesel exhaust and nitrogen oxides.

OBJECTIVES: 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.

Soluble intercellular adhesion molecules in the serum of subjects exposed to dust at different workplaces--correlation to airway symptoms, lung function, tobacco and dust exposure.

Soluble intercellular adhesion molecule 1 (s-ICAM-1) was evaluated as biomarker indicating inflammatory processes in the airways of persons exposed to salt dust, ceramic dust and flour dust. ICAM values in the serum of these workers were related to airway symptoms, lung function (FEV1), inhalable dust dose and tobacco consumption. A weak relation was found to airway symptoms (cough and phlegm) and FEV1. Consistent elevated ICAM levels in smokers suggest, that ICAM indicates inflammatory processes following strong irritants such as tobacco smoke. In contrast to lung function analysis, serum ICAM does not support inflammatory changes by salt dust or ceramic dust.