Modulation of in vitro cytokine production by aromatic hydrocarbons: indication for participation of environmental pollutants in development of allergy

Environmental pollutants (EPs) seem to play a role in development of IgE-me diated allergies. The mechanisms are poorly understood. Therefore, a suitab le cell culture system was developed for measurement of immunomodulating ef fects of EPs on human peripheral blood mononuclear cells (PBMC), Immunomodu lating effects of EPs from incineration processes (anthracene, benzo[a]pyre ne, benzo[e]pyrene, dibenz[a,h]anthracen), of 7,12-dimethylbenzo[a]anthrace ne, p-benzoquinone and 2,4-dinitro-1-fluorbenzene were measured. The pollut ants increased cytokine production of stimulated PBMC in a dose-dependent m anner. They caused individual different cytokine-profiles (Th 1- or Th2-dom inated). According to this, an individual susceptibility of donors for poll utant-dependent domination of different cytokine-profiles (Th 1 versus Th2) in immune responses can be assumed. The cytokine-profiles are correlated w ith corresponding immunoglobulin production. Th2-domination was leading to increased IgE production. We discuss the mechanisms of pollutants at the ba ck ground of signal pathways leading to Th2-domination. The individual diff erent modulation of cytokine production through pollutants gives further in dication for a causal participation of environmental pollutants in inductio n of IgE synthesis and on development of allergies.