Professional termite-control crews handle a large amount of organophosphorus insecticides such as chlorpyrifos and dichlofention (ECP), and inevitably are exposed to these insecticides throughout the spraying season. To assess the effects of exposure to organophosphates on the immune system of the insecticide applicators, subpopulation and functional subsets of lymphocytes in the blood were investigated.
Between the termite exterminators and the control group, significant differences were found in the mean levels of helper CD4+CD45RO+ cells, suppressor CD8⁺CD28^- cells and precytotoxic CD8⁺CD28⁺ cells. The termite exterminators showed lower percentages of bot CD4⁺CD45RO⁺ cells and CD8⁺CD28⁺ cells, and a higher percentage of CD8⁺CD28^- cells. In addition, a significant difference was observed in the percentages of CD20⁺ cells, which are regard as pan B cells, and both CD28⁺ cells and CD45RO⁺ cells associated with antigens of activated T cells. In the termite exterminators, the percentages of both CD28⁺ cells and CD45 RO⁺ cells decreased and the percentage of CD20⁺ cells increased.
These findings suggest that the alterations on subpopulation and functional subsets of lymphocytes in termite exterminators could be associated with the effects of chronic exposure to high doses of organophosphates on the immune system.