title: Circadian changes in granulocyte-macrophage colony-stimulating factor message in circulating eosinophils.
abstract: BACKGROUND
  Granulocyte-macrophage colony-stimulating factor (GM-CSF), which stimulates eosinophil recruitment, activation, and survival, is expressed by activated eosinophils. Although eosinophil recruitment and enhanced survival have been associated with nocturnal asthma (NA), the contribution of GM-CSF to NA is unknown.
  
  
  OBJECTIVE
  To determine whether circulating eosinophil GM-CSF expression correlates with the symptoms of NA.
  
  
  METHODS
  The GM-CSF messenger RNA (mRNA) expression at 4 PM and 4 AM was determined by reverse-transcriptase polymerase chain reaction with Southern blot analysis in subjects with and without NA and in controls.
  
  
  RESULTS
  A total of 142 asthma subjects were screened for nocturnal asthma with 1-week home peak expiratory flow rate (PEFR) monitoring. Eleven subjects had NA (>20% diurnal variation in PEFR on 4 of 7 days), and 6 met the criteria for non-NA (<10% diurnal variation in PEFR on 7 of 7 days); 8 controls were studied. In subjects with NA, GM-CSF mRNA expression in circulating eosinophils increased 3-fold at 4 AM compared with 4 PM. Diurnal changes in GM-CSF mRNA expression were not detected in the non-NA and control groups.
  
  
  CONCLUSIONS
  Day-night variation in eosinophil GM-CSF expression is associated with circadian variation in airway function in asthma, a key manifestation of asthma severity.
authors.affiliation: Waisman Center for Developmental Disabilities, Madison, Wisconsin, USA.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Esnault
authors.forename: Yulin
authors.initials: Y
authors.lastname: Fang
authors.forename: Elizabeth A B
authors.initials: EA
authors.lastname: Kelly
authors.forename: Julie B
authors.initials: JB
authors.lastname: Sedgwick
authors.forename: Jason
authors.initials: J
authors.lastname: Fine
authors.forename: James S
authors.initials: JS
authors.lastname: Malter
authors.forename: Nizar N
authors.initials: NN
authors.lastname: Jarjour
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000276:immunology*; D015139:Blotting, Southern; D002940:Circadian Rhythm / Q000276:immunology*; D004804:Eosinophils / Q000276:immunology / Q000378:metabolism*; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D012333:RNA, Messenger / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D016178:Granulocyte-Macrophage Colony-Stimulating Factor