Sputum neurokinin A in Egyptian asthmatic children and adolescents: relation to exacerbation severity.
BACKGROUND
Neurogenic inflammation may participate in the development and progression of bronchial asthma. The molecular mechanisms underlying neurogenic inflammation are orchestrated by a large number of neuropeptides including tachykinins such as neurokinin A (NKA) and substance P. Tachykinins are secreted from sensory airway nerves and inflammatory cells after allergens exposure. In clinical practice, assessment of airway inflammation is difficult. Therefore, detection of biological markers of airway inflammation in sputum might offer help for proper monitoring of asthma severity.


OBJECTIVE
We aimed to measure sputum NKA in relation to acute asthma exacerbations of varying severity.


METHODS
Sputum NKA was measured by enzyme-linked immunosorbent assay in 24 children and adolescents during and after acute asthma exacerbation and 24 healthy matched controls.


RESULTS
Sputum NKA was significantly higher in asthmatic patients during acute exacerbation than controls [217.5 (284) vs 10 (7) ng/ml, P < 0.001]. When patients with acute asthma exacerbation were followed-up till remission, sputum NKA levels decreased significantly, but they remained significantly higher than controls. Sputum NKA levels were significantly higher in severe than moderate and in moderate than mild exacerbations, and was negatively correlated to peak expiratory flow rate (r = -0.9, P < 0.001). Sputum NKA had significant positive correlations to eosinophil counts in blood and sputum (r = 0.6, P < 0.001 and r = 0.7, P < 0.001 respectively).


CONCLUSIONS
Sputum NKA is up-regulated during acute asthma exacerbation and it positively correlates to its severity. Thus, NKA may aid in objective classification of the exacerbation severity. In addition, NKA may be a target for new asthma therapy.
Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
G A
GA
Mostafa
S M
SM
Reda
M M
MM
Abd El-Aziz
S A
SA
Ahmed
D000293:Adolescent; D001249:Asthma / Q000175:diagnosis* / Q000235:genetics; D015415:Biomarkers; D016022:Case-Control Studies; D002648:Child; D004534:Egypt; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D015288:Neurokinin A / Q000032:analysis* / Q000096:biosynthesis*; D012720:Severity of Illness Index; D013183:Sputum / Q000378:metabolism*; D015854:Up-Regulation
D015415:Biomarkers; D015288:Neurokinin A