title: Serum concentrations of antibodies against vaccine toxoids in children exposed perinatally to immunotoxicants.
abstract: BACKGROUND
  Polychlorinated biphenyls (PCBs) may cause immunotoxic effects, but the detailed dose-response relationship and possible vulnerable time windows of exposure are uncertain. In this study we applied serum concentrations of specific antibodies against childhood vaccines as sentinels of immunotoxicity.
  
  
  OBJECTIVE
  The main objective was to assess the possible dependence of antibody concentrations against diphtheria and tetanus toxoids in children with regard to prenatal and postnatal PCB exposures.
  
  
  METHODS
  From a cohort of 656 singleton births formed in the Faroe Islands during 1999-2001, children were invited for examination with assessment of serum antibody concentrations at 5 years (before and after a booster vaccination) and at 7 years of age. Total PCB concentrations were determined in serum from ages 5 and 7 years, and data were also available on PCB concentrations in maternal pregnancy serum, maternal milk, and, for a subgroup, the child's serum at 18 months of age.
  
  
  RESULTS
  A total of 587 children participated in the examinations at ages 5 and/or 7 years. At age 5 years, before the booster vaccination, the antidiphtheria antibody concentration was inversely associated with PCB concentrations in milk and 18-month serum. Results obtained 2 years later showed an inverse association of concentrations of antibodies against both toxoids with PCB concentrations at 18 months of age. The strongest associations suggested a decrease in the antibody concentration by about 20% for each doubling in PCB exposure. At age 5 years, the odds of an antidiphtheria antibody concentration below a clinically protective level of 0.1 IU/L increased by about 30% for a doubling in PCB in milk and 18-month serum.
  
  
  CONCLUSIONS
  Developmental PCB exposure is associated with immunotoxic effects on serum concentrations of specific antibodies against diphtheria and tetanus vaccinations. The immune system development during the first years of life appears to be particularly vulnerable to this exposure.
authors.affiliation: Paediatric Clinic II, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Carsten
authors.initials: C
authors.lastname: Heilmann
authors.forename: Esben
authors.initials: E
authors.lastname: Budtz-Jørgensen
authors.forename: Flemming
authors.initials: F
authors.lastname: Nielsen
authors.forename: Birger
authors.initials: B
authors.lastname: Heinzow
authors.forename: Pál
authors.initials: P
authors.lastname: Weihe
authors.forename: Philippe
authors.initials: P
authors.lastname: Grandjean
mesh_terms: D000328:Adult; D000906:Antibodies / Q000097:blood*; D002648:Child; D015331:Cohort Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007107:Immune System / Q000187:drug effects*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D014612:Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000906:Antibodies; D014612:Vaccines; D011078:Polychlorinated Biphenyls