title: Children's white blood cell counts in relation to developmental exposures to methylmercury and persistent organic pollutants.
abstract: To explore possible markers of developmental immunotoxicity, we prospectively examined 56 children to determine associations between exposures to methylmercury and persistent organic pollutants since birth and the comprehensive differential counts of white blood cells (WBC) at age 5 years.
  
  
  
  Extended differential count included: neutrophils, eosinophils, basophils, lymphocytes (includingT cells, NK cells, and B cells), and monocytes. Organochlorine compounds (OCs) including polychlorinated biphenyls (PCBs) and pesticides, five perfluoroalkyl substances (PFASs), and total mercury (Hg) were measured in maternal (n=56) and children's blood at 18 months (n=42) and 5 years (n=54). We constructed latent functions for exposures at three different ages using factor analyses and applied structural equation models adjusted for covariates.
  
  
  
  Prenatal mercury exposure was associated with depleted total WBC, especially for lymphocytes, where a one standard deviation (SD) increase in the exposure was associated with a decrease by 23% SD (95% CI: -43, -4) in the cell count. Prenatal exposure to OCs was marginally associated with decreases in neutrophil counts. In contrast, the 5-year PFASs concentrations were associated with higher basophil counts (B=46% SD, 95% CI: 13, 79). Significantly reduced subpopulations of lymphocytes such as B cells, CD4-positive T helper cells and CD4 positive recent thymic emigrants may suggest cellular immunity effects and dysregulation of T-cell mediated immunity.
  
  
  
  Developmental exposure to environmental immunotoxicants appears to have different impacts on WBC counts in childhood.
authors: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors: Y
authors: Y
authors: Oulhote
authors: Institute for Inflammation Research, Department of Rheumatology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark; Department of Pediatrics and Adolescent Medicine, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors: Z
authors: Z
authors: Shamim
authors: Institute for Inflammation Research, Department of Rheumatology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark; Department of Pediatrics and Adolescent Medicine, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors: K
authors: K
authors: Kielsen
authors: Department of Occupational Medicine and Public Health, Faroese Hospital System, Tórshavn, Faroe Islands.
authors: P
authors: P
authors: Weihe
authors: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Environmental Medicine, University of Southern Denmark, Odense, Denmark. Electronic address: pgrand@sdu.dk.
authors: P
authors: P
authors: Grandjean
authors: Department of Clinical Immunology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors: L P
authors: LP
authors: Ryder
authors: Department of Pediatrics and Adolescent Medicine, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors: C
authors: C
authors: Heilmann
mesh_terms: D002675:Child, Preschool; D003718:Denmark; D004785:Environmental Pollutants / Q000032:analysis / Q000097:blood*; D005260:Female; D006197:Hair / Q000737:chemistry; D006801:Humans; D007223:Infant; D007958:Leukocyte Count; D007962:Leukocytes / Q000166:cytology*; D018811:Maternal Exposure / Q000009:adverse effects*; D008767:Methylmercury Compounds / Q000032:analysis / Q000097:blood*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood*; D011446:Prospective Studies
chemical_list: D004785:Environmental Pollutants; D008767:Methylmercury Compounds
keywords: Developmental exposure delayed effects; Immunotoxicity; Mercury; Perfluoroalkyl substances; Polychlorinated biphenyls; White blood cell count