Prenatal exposure to nickel and atopic dermatitis at age 3 years: a birth cohort study with cytokine profiles.

Nickel, the fifth most common element on Earth, is the leading inducer of contact allergies in humans, with potent immunological effects. Nickel-induced contact allergies predominantly affect females. Maternal exposure to nickel has been associated with several developmental abnormalities. However, how a maternal nickel exposure affects the development of atopic diathesis and immune abnormalities in children has never been addressed. We aimed to determine whether maternal Ni exposure affects the development of atopic dermatitis and immune abnormalities in their children. Using a birth cohort study, we analysed 140 mother-child pairs recruited in 2012-2015 from central Taiwan. Maternal exposure to nickel was estimated using urinary nickel levels measured by inductively coupled plasma mass spectrometry (ICP-MS). The serum levels of 65 analytes and IgE in 3-year-old children were profiled with a multiplex ELISA. The correlation between the maternal urinary nickel concentration and serum analyte levels was assessed using Spearmen's correlation. Multivariant regression analysis was performed to evaluate the association between maternal urinary nickel levels and serum analyte concentrations in their children. The geometric means of the maternal urinary nickel and the children's serum IgE levels were 2.27 μg/L and 69.71 IU/ml, respectively. The maternal nickel exposure was associated with increased serum levels of IL-1β, IL-2, TNF-α, and leukaemia inhibitory factor (LIF) but with decreased serum levels of matrix metalloproteinase-1 (MMP-1), IL-2R, and eotaxin-1 in the children. In addition, the development of childhood atopic dermatitis at 3 years old was significantly associated with the child's serum levels of IgE and IL-2R, but it was negatively associated with the maternal nickel exposure. This is the first study showing the potential immunological effects of maternal nickel exposure in their children at an early developmental stage.