Microbial cell wall agents as an occupational hazard.

Organic dusts cause inflammatory reactions in the tissues exposed. The lung and the cells lining the surface of the respiratory tract are a primary target. Many receptors have been shown to react specifically on the presence of microorganisms that are ubiquitous elements in organic dusts. There is a great variability in the individual response to organic dusts. Almost 50% of Caucasians are hyporesponders to LPS exposure, and people with alpha-1-antitrypsin deficiency are hyperresponsive to organic dust exposure. The diseases resulting from organic dust exposures include asthma, allergy, hypersensitivity pneumonitis and toxic pneumonitis (organic dust toxic syndrome). This paper deals with inflammation and the subsequent mechanism of disease as it is encountered in industries with these exposures. Toxicological studies including human experimental exposures and ex vivo studies of cells are described. Cellular reactions are mediated through the attachment of, e.g. LPS and beta (1,3)-D-glucan to lipopolysaccharide binding protein, CD14 and Toll-like receptors. The relation between protein release and the gene activation is described. Furthermore, studies of the individual susceptibility will be reviewed.