Background: Exposure to pesticides may affect humoral and cell-mediated immunity. Material and methods: The study group was composed of 24 men employed in the production of dust pesticides and 23 females performing ancillary jobs under conditions of lower pesticide exposure. Chronic bronchitis was diagnosed in 10 males (41.7%) and 13 females (56.5%). The workers were exposed to: triazines, carbamates and dithiocarbamates, carbendazim, captan, dodine, dichlorophenoxy acetic acid (2,4-D), and cupric oxychloride. Silica, kaolin, chalk, and talc were used as carriers. The average workplace air concentrations of pesticides did not exceed the MAC. The serum concentrations of immunoglobulins G, A and M, complement component C3, and circulating immune complexes (CIC) were estimated. The peripheral blood leukocyte count and percentage of CD3, CD4, CD8, CD19 lymphocytes were evaluated.
Results: IgA and CIC concentrations in the female group were higher as compared to controls, whereas the percentage of CD3, CD4, CD8 cells was significantly lower, as opposed to an increased percentage of CD19 cells. The male group showed lower CIC concentrations, and the C3 complement component level was significantly higher. The decreased percentage of CD3 cells was accompanied by a higher CD19 cells ratio. The white blood cell count was higher in the males. No significant changes were found in other immunity parameters.
Conclusion: The results of the study showed changes in some components of humoral and cellular immunity, which may influence damage to the respiratory system.

Keywords: dust pesticides, humoral immunity, cellular immunity