Chemotactic activity of human polymorphonuclear leukocytes and industrial xenobiotics: a brief review

This review deals with some of our contributions to the use of chemotaxis, as a tool in evaluating effects of industrial xenobiotics on PMN, either in vitro or ex vivo. In vitro experiments have shown that lead, arsenic, styrene and 2,5-hexanedione, a major neurotoxicant metabolite of n-hexane, reduce chemotaxis. The most important results of ex vivo experiments have confirmed those obtained in vitro with styrene and 2,5-hexanedione: a significant reduction of chemotaxis was indeed observed in PMN harvested from workers exposed to low levels of n-hexane or styrene who did not show any sign of biochemical or clinical alteration. After 3 weeks under non-exposed conditions, the chemotactic indexes were markedly increased in most of the workers which were exposed to styrene and in all the workers exposed to n-hexane, all of whom have shown a reduced chemotaxis at the first blood sampling. Moreover chemotaxis was found to be significantly reduced at relative low levels of lead: results of the in vitro and ex vivo experiments show a comparable ranking of midpoint inhibition concentrations. We are only at the dawn of the understanding of the relation between occupational xenobiotics and PMN chemotaxis. This research area is still promising for the future, since PMN chemotaxis seems to be adequate and it must therefore enter in well-defined study protocols for investigating the potential immunotoxicity of occupational chemicals to which humans are exposed at low levels.