CROSS-SHIFT CHANGES IN BLOOD INFLAMMATORY MARKERS OCCUR IN THE ABSENCE OF AIRWAY-OBSTRUCTION IN WORKERS EXPOSED TO GRAIN DUST

Grain dust is well known to cause both acute and chronic respiratory d isorders, and endotoxins are considered key components in this. Since endotoxins are known to elicit proinflammatory mediators, we investiga ted cytokine (tumor necrosis factor [TNF], interleukin-6, interleukin- 8) release and a number of proinflammatory and anti-inflammatory prote ins (soluble TNF receptors, lipopolysaccharide (LPS) binding protein, bactericidal permeability increasing protein (BPI), C-reactive protein ) in plasma of workers exposed to grain dust. In two surveys during 1 week, lung function was measured daily before and after the shift, usi ng flow-volume curves and/or forced oscillation measurements. On Monda y and Friday, blood samples (30 mL) were drawn and cytokine release wa s determined by enzyme-linked immunosorbent assay in supernatant of is olated monocytes or whole blood culture, either unstimulated or on the ex vivo stimulation with 3 ng/mL or 1,000 ng/mL endotoxin. Individual exposures were determined from stationary dust measurements at every workplace combined with personal task analysis during all shifts. In b oth surveys, no cross-week change in lung function parameters was obse rved. In the first survey (average exposure: 20.2 mg/m(3)), monocyte s pontaneous TNF release was increased sevenfold cross week (p<0.001) an d was significantly related both to individual dust exposure (r=0.62) of that week and the increase in soluble TNF receptor 75 kD (r=0.85). In the second survey, where average exposure was much lower (3.67 mg/m (3)), impedance parameters indicated a significant improvement of airw ay function, and cross-week changes in inflammatory markers were minim al. Therefore, we conclude that inflammatory events can be used to mon itor adverse respiratory effects of moderate grain dust exposure.