Circadian changes in granulocyte-macrophage colony-stimulating factor message in circulating eosinophils.
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.
Esnault
Stéphane
S
Waisman Center for Developmental Disabilities, Madison, Wisconsin, USA.
Fang
Yulin
Y
Kelly
Elizabeth A B
EA
Sedgwick
Julie B
JB
Fine
Jason
J
Malter
James S
JS
Jarjour
Nizar N
NN
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
D012333:RNA, Messenger; D016178:Granulocyte-Macrophage Colony-Stimulating Factor