title: Elevated eosinophil protein X in urine from healthy neonates precedes development of atopy in the first 6 years of life.
abstract: BACKGROUND
  Biomarkers predicting development of atopic disease are needed for targeted preventive measures and to study if disease pathology may be active before onset of symptoms.
  
  
  OBJECTIVE
  To investigate whether eosinophil protein X, leukotriene-C4/D4/E4, and 11β-prostaglandin (PG) F2α (PGD2 metabolite) assessed in urine from healthy at-risk neonates precede development of atopic disease during the first 6 years of life.
  
  
  METHODS
  We measured eosinophil protein X (n = 369), leukotriene-C4/D4/E4 (n = 367), and 11β-PGF2α (n = 366) in urine from 1-month-old children participating in the Copenhagen Prospective Studies on Asthma in Childhood birth cohort. Clinical data on development of allergic sensitization, allergic rhinitis, nasal eosinophilia, blood eosinophilia, eczema, troublesome lung symptoms (significant cough or wheeze or dyspnea), and asthma were collected prospectively until age 6 years. Associations between urinary biomarkers and development of atopic traits were investigated using general estimating equations, logistic regression, and Cox regression.
  
  
  RESULTS
  Eosinophil protein X in the urine of the asymptomatic 1-month-old neonates was significantly associated with development of allergic sensitization (odds ratio, 1.49; 95% confidence interval [CI], 1.08–1.89), nasal eosinophilia (odds ratio, 3.2; 95% CI, 1.2–8.8), and eczema (hazard ratio, 1.4; 95% CI, 1.0–2.0), but not with allergic rhinitis, asthma, or blood eosinophilia. Neither leukotriene-C4/D4/E4 nor 11β-PGF2α was associated with any of the atopic phenotypes.
  
  
  CONCLUSIONS
  Eosinophil protein X in urine from asymptomatic neonates is a biomarker significantly associated with later development of allergic sensitization, nasal eosinophilia, and eczema during the first 6 years of life. These findings suggest activation of eosinophil granulocytes early in life before development of atopy-related symptoms.
authors.affiliation: Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Copenhagen, Denmark
authors.forename: Bo Lund Krogsgaard
authors.initials: BL
authors.lastname: Chawes
authors.forename: Klaus
authors.initials: K
authors.lastname: Bønnelykke
authors.forename: Hans
authors.initials: H
authors.lastname: Bisgaard
mesh_terms: D015415:Biomarkers / Q000652:urine; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D047208:Eosinophil-Derived Neurotoxin / Q000652:urine*; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000652:urine*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016017:Odds Ratio; D011453:Prostaglandins / Q000652:urine; D013189:SRS-A / Q000652:urine
chemical_list: D015415:Biomarkers; D011453:Prostaglandins; D013189:SRS-A; D047208:Eosinophil-Derived Neurotoxin; C479221:RNASE2 protein, human