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• Associations between cadmium exposure and cellular immune responses were examined. • Prenatal cadmium exposure was associated with reduced T lymphocyte subsets and increased Th2 cytokines. • The effects of prenatal cadmium exposure on cellular immune responses primarily occurred in females. • No clear associations between children's concurrent cadmium exposure and cellular immune responses were observed. Experimental studies have demonstrated that cadmium exposure induces alterations on immune function, but epidemiological evidence is lacking. To examine the associations between prenatal and postnatal cadmium exposure and cellular immune responses among pre-school children. Pre-school aged children (n = 407) were followed from a prospective birth cohort study in Wuhan, China. Maternal urinary and children's plasma cadmium concentrations were measured as biomarkers of prenatal and postnatal cadmium exposure, respectively. Children's cellular immune responses were assessed by peripheral blood T lymphocyte subsets and plasma cytokines. Multivariable adjusted models were applied to estimate the associations of prenatal and postnatal cadmium exposure with T lymphocyte subsets and cytokines, and the effect modification by child gender were also examined. Maternal urinary cadmium was associated with reduced absolute counts of CD3+CD4+ cells (−12.45%; 95% CI: −23.74%, 0.40% for the highest vs. lowest quartile; p for trend = 0.045). Inverse associations of maternal urinary cadmium with %CD3+CD4+ cells and CD4+/CD8+ ratio were only observed among females (both p-interaction < 0.050); whereas an inverse association with absolute counts of CD3+CD8+ cells was only observed among males (p-interaction = 0.057). Positive associations of maternal urinary cadmium with %CD3+CD4+ cells, interleukin-4 (IL-4), and IL-6 were only observed among females, although there were no significant interactions. We observed no clear associations of children's plasma cadmium with T lymphocyte subsets and cytokines. Prenatal but not postnatal cadmium exposure was associated with sex-specific alterations on children's cellular immune responses. [ABSTRACT FROM AUTHOR]

Exposure to air pollution has been linked with altered immune function in adults, but little is known about its effects on early life. This study aimed to investigate the effects of exposure to air pollution during prenatal and postnatal windows on cell-mediated immune function in preschoolers. Pre-school aged children (2.9 ± 0.5 y old, n = 391) were recruited from a mother-child cohort study in Wuhan, China. We used a spatial-temporal land use regression (LUR) model to estimate exposures of particulate matter with aerodynamic diameters ≤2.5 μm (PM 2.5) and ≤10 μm (PM 10), and nitrogen dioxide (NO 2) during the specific trimesters of pregnancy and the first two postnatal years. We measured peripheral blood T lymphocyte subsets and plasma cytokines as indicators of cellular immune function. We used multiple informant models to examine the associations of prenatal and postnatal exposures to air pollution with cell-mediated immune function. Prenatal exposures to PM 2.5 , PM 10 , and NO 2 during early pregnancy were negatively associated with %CD3+ and %CD3+CD8+ cells, and during late pregnancy were positively associated with %CD3+ cells. Postnatal exposures to these air pollutants during 1-y or 2-y childhood were positively associated with IL-4, IL-5, IL-6, and TNF-α. We also observed that the associations of prenatal or postnatal air pollution exposures with cellular immune responses varied by child's sex. Our results suggest that exposure to air pollution during different critical windows of early life may differentially alter cellular immune responses, and these effects appear to be sex-specific. [Display omitted] • Effects of air pollution exposure on cell-mediated immune responses were estimated. • Late pregnancy air pollution exposures were positively related to %CD3+ cells. • Early pregnancy air pollution exposures were related to reduced %CD3+ and %CD3+CD8+ cells. • Postnatal air pollution exposures were positively associated with certain cytokines. • There were sex-specific associations between air pollution exposures and immune responses. [ABSTRACT FROM AUTHOR]