Immunological abnormalities 17 years after accidental exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin

Eighteen workers were reviewed 17 years after accidental exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). Clinical assessment showed that they were in good health. A study of several biochemical and immunological parameters in these subjects and in 15 carefully matched controls showed no difference in serum concentrations of hepatic enzymes between exposed workers and controls. Although mean serum concentrations of cholesterol and triglyceride were higher in exposed subjects than in controls, the results did not reach statistical significance. Antinuclear antibodies and immune complexes were detected significantly more frequently in the peripheral blood of workers exposed to dioxin. There was no significant difference between exposed workers and controls in the number of T lymphocytes, B lymphocytes, and helper and suppressor T cell counts in peripheral blood, but the number of natural killer cells identified by the monoclonal antibody Leu-7 was significantly higher in workers exposed to dioxin.