title: Spontaneous cytokine production in children according to biological characteristics and environmental exposures.
abstract: BACKGROUND
  Environmental factors are likely to have profound effects on the development of host immune responses, with serious implications for infectious diseases and inflammatory disorders such as asthma.
  
  
  OBJECTIVE
  This study was designed to investigate the effects of environmental exposures on the cytokine profile of children.
  
  
  METHODS
  The study involved measurement of T helper (Th) 1 (interferon-gamma), 2 [interleukin (IL)-5 and IL-13], and the regulatory cytokine IL-10 in unstimulated peripheral blood leukocytes from 1,376 children 4-11 years of age living in a poor urban area of the tropics. We also assessed the impact of environmental exposures in addition to biological characteristics recorded at the time of blood collection and earlier in childhood (0-3 years before blood collection).
  
  
  RESULTS
  The proportion of children producing IL-10 was greater among those without access to drinking water [p < 0.05, chi-square test, odds ratio (OR) = 1.67]. The proportion of children producing IL-5 and IL-10 (OR = 10.76) was significantly greater in households that had never had a sewage system (p < 0.05, trend test).
  
  
  CONCLUSIONS
  These data provide evidence for the profound effects of environmental exposures in early life as well as immune homeostasis in later childhood. Decreased hygiene (lack of access to clean drinking water and sanitation) in the first 3 years of life is associated with higher spontaneous IL-10 production up to 8 years later in life.
authors.affiliation: Instituto de Ciências da Saúde, Universidade Federal de Bahia, Salvador, Brazil. cavfigueiredo@gmail.com
authors.forename: Camila Alexandrina
authors.initials: CA
authors.lastname: Figueiredo
authors.forename: Neuza Maria
authors.initials: NM
authors.lastname: Alcântara-Neves
authors.forename: Rafael
authors.initials: R
authors.lastname: Veiga
authors.forename: Leila D
authors.initials: LD
authors.lastname: Amorim
authors.forename: Vitor
authors.initials: V
authors.lastname: Dattoli
authors.forename: Lívia Ribeiro
authors.initials: LR
authors.lastname: Mendonça
authors.forename: Samuel
authors.initials: S
authors.lastname: Junqueira
authors.forename: Bernd
authors.initials: B
authors.lastname: Genser
authors.forename: Mariese
authors.initials: M
authors.lastname: Santos
authors.forename: Lain Carlos Pontes
authors.initials: LC
authors.lastname: de Carvalho
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Cooper
authors.forename: Laura
authors.initials: L
authors.lastname: Rodrigues
authors.forename: Maurício L
authors.initials: ML
authors.lastname: Barreto
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006801:Humans; D007107:Immune System / Q000187:drug effects*; D007371:Interferon-gamma / Q000097:blood*; D016753:Interleukin-10 / Q000097:blood*; D018793:Interleukin-13 / Q000097:blood*; D015848:Interleukin-5 / Q000097:blood*; D008297:Male; D012722:Sewage / Q000009:adverse effects; D014881:Water Supply / Q000032:analysis
chemical_list: D004785:Environmental Pollutants; D018793:Interleukin-13; D015848:Interleukin-5; D012722:Sewage; D016753:Interleukin-10; D007371:Interferon-gamma