Associations between prenatal and postnatal lead exposure and preschool children humoral and cellular immune responses.

Studies have shown that lead exposure affected the immune function, but few studies have examined the re-lationships between in utero lead exposure, a sensitive period that is important for immune development, and later immune responses. To investigate the effects of prenatal and childhood lead exposure on the preschool-aged children's immune responses, a prospective birth cohort study was established in Wuhan, China, in which lead concentrations were analyzed in maternal urine during the third trimester and in plasma samples from children aged about 3 years. We assessed immune responses by measuring immune cytokines in the children's plasma (n = 326) and peripheral blood T lymphocyte subsets (n = 394) at 3 years of age. Each unit increase in maternal urinary lead concentration (mu g/g creatinine) was associated with reduced IL-10 (beta =-5.93%, 95%CI:-11.82%,-0.03%) and reduced IL-4 levels (beta =-5.62%, 95%CI:-10.44%,-0.80%). Lead in children's plasma (mu g/L) was associated with significant increase in TNF-alpha (beta = 10.78%, 95%CI: 3.97%, 17.59%). No statistically significant relationship of childhood lead exposure with T lymphocyte subsets was observed. The study suggested prenatal and childhood lead exposure was associated with changes in preschool children's plasma cytokine levels.