Identifying critical windows of susceptibility to perinatal lead exposure on child serum vaccine antibody levels

Abstract

Background: Mounting evidence suggests that early-life lead exposure alters immune system functions, including T-cell dependent antibody responses to childhood immunizations. However, no studies have identified critical windows of susceptibility to lead exposure.

Aim: To identify perinatal critical windows of lead exposure that are associated with antibody responses to anti-MMR (anti-measles, -mumps, and -rubella virus) and anti-DTP (anti-diphtheria, -tetanus, and -pertussis toxoids) vaccinations in Hispanic school-aged (mean± standard deviation: 4.8±0.6 years) children.

Methods: Weekly lead exposure-from 16 weeks before to 14 weeks after birth-was measured in deciduous teeth from 271 children enrolled in the PROGRESS study. Serum levels of anti-MMR and anti-DTP antibodies were measured by a Luminex-multiplexed-microbead-array immunoassay. Time-varying associations between log2-transformed dentine lead concentrations and log2-transformed antibody levels were estimated by fitting distributed lag non-linear models.

Results: A two-fold higher dentine lead concentration in the first three weeks postpartum was associated with an average -4.29% lower anti-tetanus level (95%confidence interval(CI):-8.22,-0.20). A perinatal (one week before to one week after birth) critical window of lead exposure demonstrated an average -3.44% (95%CI:-7.05;0.30) lower anti-diphtheria antibody level.

Conclusions: Our study suggests that early-life lead exposure may contribute to immune dysfunction by reducing children's antibody responses to scheduled vaccinations.

Keywords: T cell; adaptive immune system; dentine; distributive lag models; immune system; immunotoxicology; pediatrics.