Impact of prenatal pyrethroid pesticide exposure on neonatal lymphocyte subsets and apoptosis: a birth cohort study

Background: Prenatal pyrethroid pesticides (PYRs) exposure may elevate infection diseases susceptibility of children. However, it is unclear the relationship of PYRs exposure and neonatal immune function. We explored the association of PYRs exposure during three trimesters with neonatal immunity and the roles of lymphocyte apoptosis. Methods: Maternal urinary PYRs metabolites (3PBA, 4F3PBA, cis-DBCA) were measured in each trimester. Cord blood lymphocyte subsets and lymphocyte apoptosis rates were assessed by flow cytometry. Multivariate linear regression models were used to examine the associations of trimester-specific and repeated PYRs exposure during pregnancy with neonatal immune function. Results: T cell counts (β = -0.13; 95% CI = -0.22, -0.04), B cell counts (β = -0.10; 95% CI = -0.20, -0.01), and NK cell counts (β = -0.14; 95% CI = -0.25, -0.03). High-level 3PBA exposure in the first trimester (β = 0.11; 95% CI = 0.01, 0.22) and high-level cis-DBCA exposure in the second trimester (β = 0.16; 95% CI = 0.04, 0.28) were positively associated with cord blood lymphocyte apoptosis rates. Repeated high-level cis-DBCA exposure in two or more trimesters was associated with increased cord blood lymphocyte apoptosis rates (β = 0.19; 95% CI = 0.03, 0.35). Conclusions: High-level maternal PYRs exposure during pregnancy may reduce neonatal lymphocyte counts and increase lymphocyte apoptosis. These effects persist throughout gestation, with the third trimester may represent a sensitive window for adverse effects on immune development.