Studies of human volunteers who were exposed to swine dust have revealed a range of effects on respiratory mucosa after exposure. This experimental study measured the in vitro cytokine release in blood of healthy farmers after incubation with aqueous extracts of LPS, b-1,3-D-glucan and Aspergillus fumigatus in a whole blood assay (WBA).

From an ongoing study of young farmers we recruited 46 healthy farmers. From each farmer 10 ml of EDTA blood was collected and exposed to aqueous extracts of LPS from E. coli, b-1,3-D-Glucan (Curdlan) and Aspergillus fumigatus. No release of cytokines was seen in the WBA after exposure to Aspergillus fumigatus suspensions. Smoking strongly attenuated in vitro cytokine release from blood cells in a WBA. The cytokine release in the present study was from 1.5 times higher for IL-6 after LPS II exposure to 4.6 times higher for TNF after exposure to b-1,3-D-glucan. The release of cytokines was almost the same for 0.5 µg/ml LPS as for 250 µg/ml b-1,3-D-glucan. In conclusion this study shows that smoking is a confounder in studies of the release of proinflammatory cytokines in a WBA. Furthermore LPS is a 500 times more potent inducer of the proinflammatory cytokine release compared to b-1,3-D-glucan in WBA on a weight basis.