title: Production of interleukin-5, -10 and interferon-γ in cord blood is strongly associated with the season of birth.
abstract: BACKGROUND
  The effect of labour and different labour-related factors on the cord blood (CB) cell cytokine production is still relatively unknown.
  
  
  OBJECTIVE
  To study the relationships between the production of IL-5, IL-10 and IFN-γ in CB samples and maternal, early neonatal and birth-related factors.
  
  
  METHODS
  Whole-blood samples were collected after birth (n=423) and they were stimulated for 24 and 48 h with a combination of phorbol ester and ionomycin. Production of IL-5, IL-10 and IFN-γ was determined using ELISA. Maternal, early neonatal and birth-related variables were recorded prospectively during pregnancy, and during and after delivery.
  
  
  RESULTS
  After multivariable adjustment for confounders, the strongest predictor of IL-5, IL-10 and IFN-γ production in CB cell samples was the season of birth. Children born in the spring had significantly lower cytokine responses compared with those born in the fall. IL-5 production was inversely associated with female gender of the child and maternal smoking. If corrections for white blood cell (WBC) counts were not performed, IL-5 production was also significantly associated with the mode of delivery. Respectively, the production of IL-10 and IFN-γ was inversely associated with prostaglandin induction before birth.
  
  
  CONCLUSIONS
  Environmental exposure to pollen and ultraviolet irradiation during gestation may have an effect on the cytokine profile of the offspring in CB because children born in the spring or winter showed the lowest IL-5, IL-10 and IFN-γ responses. The production of IL-10 and IFN-γ was also inversely associated with prostaglandin labour induction before birth. Other labour-related factors were not significantly associated with production of IL-5, IL-10 and IFN-γ after WBC count correction.
authors.affiliation: Department of Environmental Health, National Institute for Health and Welfare, Kuopio, Finland. leea.keski-nisula@kuh.fi
authors.forename: L
authors.initials: L
authors.lastname: Keski-Nisula
authors.forename: M H J
authors.initials: MH
authors.lastname: Lappalainen
authors.forename: K
authors.initials: K
authors.lastname: Mustonen
authors.forename: M-R
authors.initials: MR
authors.lastname: Hirvonen
authors.forename: P I
authors.initials: PI
authors.lastname: Pfefferle
authors.forename: H
authors.initials: H
authors.lastname: Renz
authors.forename: J
authors.initials: J
authors.lastname: Pekkanen
authors.forename: M
authors.initials: M
authors.lastname: Roponen
mesh_terms: D001773:Blood Cells / Q000187:drug effects / Q000276:immunology* / Q000528:radiation effects; D016009:Chi-Square Distribution; D036861:Delivery, Obstetric / Q000379:methods; D004768:Enterotoxins / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology*; D005387:Finland; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D016753:Interleukin-10 / Q000097:blood*; D015848:Interleukin-5 / Q000097:blood*; D015759:Ionomycin / Q000494:pharmacology; D007958:Leukocyte Count; D007964:Leukocytosis / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D011058:Pollen / Q000276:immunology; D011247:Pregnancy; D011446:Prospective Studies; D011453:Prostaglandins / Q000627:therapeutic use; D018570:Risk Assessment; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D004768:Enterotoxins; C508609:IL10 protein, human; C508599:IL5 protein, human; D015848:Interleukin-5; D008070:Lipopolysaccharides; D011453:Prostaglandins; D016753:Interleukin-10; C031818:enterotoxin B, staphylococcal; D015759:Ionomycin; D007371:Interferon-gamma; D013755:Tetradecanoylphorbol Acetate