Circulating neutrophil CD14 expression and the inverse association of ambient particulate matter on lung function in asthmatic children.
BACKGROUND
Identifying baseline inflammatory biomarkers that predict susceptibility to size-specific particulate matter (PM) independent of gaseous pollutants could help us better identify asthmatic subpopulations at increased risk for the adverse health effects of PM.


OBJECTIVE
To evaluate whether the association between lung function and exposure to ambient levels of PM less than 2.5 microm in diameter (PM2.5) (fine) and 10 to 2.5 microm in diameter (PM(10-2.5)) (coarse) in children with persistent asthma differed across baseline measures of inflammation and innate immune activation.


METHODS
We performed a panel study on a local population of 16 children with persistent asthma and evaluated daily pulmonary function (percentage of predicted peak expiratory flow and forced expiratory volume in 1 second) while concurrently measuring daily PM2.5 and PM(10-2.5) exposure from a central site in Chapel Hill, North Carolina. The children underwent a baseline medical evaluation that included assessment of several immunoinflammatory biomarkers in peripheral blood.


RESULTS
Children without measurable CD14 expression on circulating neutrophils had significantly reduced pulmonary function (forced expiratory volume in 1 second and peak expiratory flow) with each interquartile range (IQR) increase in PM2.5 (IQR = 8.5 microg/m3) and PM(10-2.5) (IQR = 4.1 microg/m3) concentration, unlike children with measurable CD14 expression (P < .001 for interaction).


CONCLUSIONS
Asthmatic children with muted surface expression of CD14 on circulating neutrophils may have a decreased capacity to respond to bacterial components of PM.
Svendsen
Erik R
ER
Office of Research and Development, EPA, Research Triangle Park, North Carolina 29208, USA. svendsee@gwm.sc.edu
Yeatts
Karin B
KB
Peden
David
D
Orton
Susan
S
Alexis
Neil E
NE
Creason
John
J
Williams
Ronald
R
Neas
Lucas
L
D000293:Adolescent; D015703:Antigens, CD / Q000032:analysis / Q000097:blood; D001249:Asthma / Q000276:immunology* / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D001772:Blood Cell Count; D001944:Breath Tests; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000032:analysis* / Q000097:blood; D008168:Lung / Q000276:immunology* / Q000503:physiopathology; D008297:Male; D017817:Nasal Lavage Fluid / Q000166:cytology; D009504:Neutrophils / Q000737:chemistry / Q000166:cytology / Q000276:immunology*; D009657:North Carolina; D052638:Particulate Matter / Q000009:adverse effects / Q000032:analysis / Q000276:immunology*; D010366:Peak Expiratory Flow Rate; D012129:Respiratory Function Tests; D013147:Spirometry; D013696:Temperature
D015703:Antigens, CD; D015415:Biomarkers; D018950:Lipopolysaccharide Receptors; D052638:Particulate Matter