Cytokine patterns in greenhouse workers occupationally exposed to α-cypermethrin: An observational study

• Pyrethroid exposure did not induce clinical signs of immunosuppression.
• Pyrethroids significantly affected the levels of some cytokines in exposed subjects.
• Low IL-12p70, IL-2, IL-8, γ-IFN may inhibit NK cell and cytotoxic T-cell activation.
• Pyrethroid exposure may reduce host defenses against infection and cancer.

The immunotoxicity of the synthetic pyrethroid α-cypermethrin (αCYP) was assessed in 30 occupationally exposed greenhouse workers and 30 non-exposed controls by comparing plasma levels of IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, TNF-α, TNF-β and INF-γ. Urinary 3-phenoxybenzoic acid was used as an exposure biomarker.Exposed workers showed neither clinical signs of immunosuppression nor alterations in total leukocytes or leukocyte subpopulations, whereas significant differences (p < 0.05) were found for IL-12p70 and highly significant differences (p < 0.001) for INF-γ, IL-2 and IL-8, which are involved in antitumor immunity and response to infection.Proinflammatory cytokines IL-2, IL-8, IL-12p70 and IFN-γ play a significant role against infection and cancer.We report the first data on the ability of αCYP to reduce proinflammatory cytokine levels in an exposed healthy human population. Findings support the hypothesis that pyrethroid exposure may reduce host defenses against infection and cancer, particularly in subjects with impaired immune capacity.