IMMUNOLOGICAL FINDINGS IN WORKERS FORMERLY EXPOSED TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN AND ITS CONGENERS

One hundred ninety-two workers in a German pesticide factory who were exposed to polychlorinated dibenzodioxins and -furans (PCDD/PCDF) were investigated for former and present diseases and laboratory changes o f the immune system. Moreover, in a subgroup of 29 highly exposed and 28 control persons, proliferation studies were performed. in addition to assays such as blood count, immunoglobulins, serum electrophoresis, monoclonal bands, surface markers, autoantibodies, and lymphocyte pro liferation, two new methods, the rise of tetanus antibody concentratio n after vaccination and the in vitro resistance of lymphocytes to chro mate, were used to diagnose the morphologic and functional stale of th e immune system. There was no stringent correlation of actual PCDD/PCD F concentrations with the occurrence of infections or with one of the immune parameters. In addition, outcomes of the tetanus vaccination an d the chromate resistance test were not correlated with PCDD/PCDF. How ever, the chromate resistance of lymphocytes stimulated by phytohemagg lutinin of highly exposed persons was significantly lower than that fo r the control group. These findings indicate that the function of lymp hocytes can be stressed and possibly impaired by high exposure to PCDD /PCDF.