Sputum eosinophil apoptotic rate is positively correlated to exhaled nitric oxide in children.
OBJECTIVE
Exhaled nitric oxide (FE(NO)), a potential biomarker for asthma, is positively correlated with eosinophilic airway inflammation. Eosinophil apoptotic rate (AR) may be increased by NO but the relationship between eosinophil AR and NO has not been studied in vivo. This study tested the hypothesis that eosinophil AR will be positively related to FE(NO).


METHODS
Children with and without asthma were recruited and participated in an assessment that included FE(NO) measurement, skin prick reactivity, spirometry, and sputum induction. The absolute sputum eosinophil count and eosinophil AR were determined by morphology under light microscope after staining.


RESULTS
There were 31 children recruited, mean age 11 years, 21 were asthmatic and 19 were boys. The median FE(NO) (range) was 15.6 parts per billion (3.1-102.6), 17 were atopic and the mean (SD)% FEV(1) was 85 (10)%. Sputum eosinophil AR was determined in 19 children (16 asthmatics), mean (SD) value 0.49 (0.13). There were positive relationships between eosinophil AR and FE(NO) (Spearman rho = 0.46, P = 0.046), eosinophil AR and % eosinophil count (Spearman rho = 0.45, P = 0.050) and also FE(NO) and % eosinophil count (Spearman rho = 0.49, P = 0.024).


CONCLUSIONS
There is a positive relationship between FE(NO) and eosinophil AR. Nitric oxide may be involved in regulation of eosinophil AR in the airways.
Pontin
Jennifer
J
Department of Child Health, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.|School of Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
Blaylock
Morgan G
MG
School of Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
Walsh
Garry M
GM
School of Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
Turner
Stephen W
SW
Department of Child Health, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
D000293:Adolescent; D017209:Apoptosis / Q000276:immunology*; D001249:Asthma / Q000276:immunology*; D015415:Biomarkers; D001944:Breath Tests / Q000379:methods; D002648:Child; D004802:Eosinophilia / Q000276:immunology*; D004804:Eosinophils / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000032:analysis* / Q000276:immunology; D013183:Sputum / Q000276:immunology*
D015415:Biomarkers; D009569:Nitric Oxide