Plasma 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) levels and immune response

For determination of whether plasma 1,1-dichloro-2,2-bis(p-chlorophenyl)eth yl (DDE) pesticide levels (less than or equal to1-32 ppb) are associated wi th immune suppression or DNA damage in lymphocytes, 302 individuals residin g in Moore County, North Carolina, in 1994-1996 provided a blood specimen, underwent a skin test, and answered a questionnaire concerning factors affe cting plasma organochlorine pesticide levels and the immune system. The blo od specimens were analyzed for levels of plasma DDE (a metabolite of 1,1,1- trichloro-2,2-bis(p- chlorophenyl)ethane), numbers and types of blood cells , immunoglobulin levels, mitogen-induced lymphoproliferative activity, and lymphocyte micronuclei. When DDE levels were categorized as 1 or less, more than 1 to 2, more than 2 to 4.3, more than 4.3 to 7.6, and more than 7.6 p pb, individuals with higher plasma DDE levels had lowered mitogen-induced l ymphoproliferative activity (concanavalin A, range: 74,218 dropping to 55,8 80 counts per minute, p = 0.03) and modestly increased total lymphocytes (r ange: 2.0-2.3 x 10(3)/mul, p = 0.05) and immunoglobulin A levels (range: 21 0-252 mg/dl, p = 0.04). There were no consistent differences in response to the skin tests by plasma DDE levels. Plasma DDE levels were not associated with a higher frequency of micronuclei. The authors conclude that relative ly low levels of plasma DDE are associated with statistically significant c hanges in immune markers, although the magnitude of the effects are of unce rtain clinical importance.