Acute changes in sputum IL-10 following underground exposure to diesel exhaust

Introduction. Although exposure to diesel exhaust has been linked with adverse health effects, little is known about the acute effects of exposure in the underground workplace. Methods. Cross-shift spirometry and sputum induction were completed on twelve subjects associated with comminuted rock removal (mucking) operations in all underground copper mine using diesel powered and pneumatic equipment on separate days, and sputum collected on a baseline non-exposure day as well. Results. For diesel operations, elemental carbon exposure averaged 538 +/- 512 mu g/m(3) during the 1-2 hour operations. Sputum interleukin-10 decreased with diesel exhaust using one ELISA assay (3.69 v. 2.32 pg/ml, p = 0.015), but increased when measured with a different ELISA kit (0.18 v. 0.59 pg/ml, p = 0.019), consistent with an overall decline in IL-10 protein concentration but an increase in the biologically active form. Sputum interleukin-6 decreased with exposure to diesel exhaust, although this change lost statistical significance when restricted to non-smokers. There were no significant changes in spirometry, interleukins 1 beta, 4, and 8, tumor necrosis factor alpha or 8-hydroxy-2'-deoxyguanosine. Conclusion. High levels of diesel exhaust can result in rapid changes in Sputum IL-10, suggesting possible protein modification.