By Saikosaponin-B2 Increased levels of elastase known to be increased in neutrophilic inflammation. Neutrophil elastase has a proteolytic effect on membrane bound CD14 by releasing the receptor into extracellular medium. As farmers have increased proportion of blood Th2 cells producing IL-4 and IL-13, this may contribute to the explanation as Th2 Pseudoginsenoside-F11 cytokines, e g IL-4, have the ability to reduce surface expression of CD14. We observed decreased sputum levels of sCD14 in the farmers. Farmers regularly inhale high amounts of LPS that binds to sCD14 which therefore may not be detectable with the ELISA method used. It might also be related to the decreased proportion of sputum macrophages in farmers as we observed a correlation between sCD14 and number of sputum macrophages indicating that macrophages may be an important producer of sCD14. Increased levels of sST2 are induced by pro-inflammatory stimuli such as LPS and TNF. Serum levels of sST2 are increased in several inflammatory disorders and intravenous injection of LPS increases serum levels of sST2 dramatically in healthy subjects. The attenuated response in serum sST2 release after exposure in a pig house and LPS challenge in the farmers might be due to tolerance. As systemic cytokine responses are attenuated in farmers this may, in part, explain the weaker sST2 increase in serum following exposure in pig barns in this group. We have, in a previous study, observed increased concentration of blood neutrophils in farmers compared to unexposed controls, a finding that was not confirmed in the present study. This might be due to differences in exposure between the participating farmers. There is heterogeneity in previous exposure within the group of pig farmers with great variation in the cumulative exposure depending on the duration of employment and length of the working days. Thus, the possible difference in pre-trial cumulative exposure and the small study groups may have influenced the possibilities to detect differences between the groups. However, despite this our study revealed some relevant and important new findings. In conclusion, farmers showed altered expression of adhesion proteins on blood neutrophils, altered expression and soluble levels of PRR in the airways and attenuated release of sST2 after exposure in a pig barn and after a bronchial LPS challenge. The altered response in the farmers is probably caused by chronic exposure in pig barn environment and may be of pathogenic importance in development of chronic airway diseases, such as chronic bronchitis and increased occurrence of colonization of bacteria in the airways, conditions that are frequently observed in this group. The direct conversion of low potential electrons into hydrogen by microbial organisms is a prospective biotechnological process for the renewable hydrogen production as an energy carrier.