title: Correlation between nitrites in induced sputum and asthma symptoms in asthmatic schoolchildren.
abstract: OBJECTIVE
  To determine if nitrites (nitric oxide metabolites) measured in induced sputum decrease and correlate with improvement of clinical asthma symptoms after treatment, we performed a prospective longitudinal study in a tertiary care hospital in Arequipa, Peru.
  
  
  METHODS
  In 95 schoolchildren with mild and moderate persistent asthma we determined nitrites in induced sputum samples (measured using the Griess assay). Clinical parameters and exercise bronchial challenge (EBC) test were performed twice, at baseline and after 3 months of beclomethasone-dipropionate treatment (median doses: 300 mcg/day, IQR: 300-450).
  
  
  RESULTS
  Sixty out of 95 children completed the study (median age of 9-year [IQR: 7-13]). A significant change in sputum nitrites levels between admission and the end of the study was observed (34.4 nmol/ml [IQR:18.2-58.4] and 11.2 nmol/ml [6-20.1], respectively, P = < 0.0001). Also a significant correlation between decrease of sputum nitrites levels and improvement of clinical parameters (acute exacerbations [r = 0.361, P = 0.005]; use of salbutamol [r = 0.322, P = 0.013]; emergency visits [r = 0.275, P = 0.033]; and school absence [r = 0.41, P = 0.001]) from admission to the end of the study was found. However, sputum nitrites levels did not correlated with peripherical blood eosinophils or serum IgE levels or with EBC test at any point of the study. The decrease of sputum nitrites levels after the treatment was significant in each asthma group (mild and moderate), but not between groups.
  
  
  CONCLUSIONS
  This study showed that measured nitrite in induced sputum (a simple and cheap non-invasive method) is a good alternative for monitoring asthmatic treatment in schoolchildren.
authors.affiliation: Department of Pediatrics, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Castro-Rodriguez
authors.forename: Ronald O
authors.initials: RO
authors.lastname: Molina
authors.forename: Marco
authors.initials: M
authors.lastname: Cáceres
authors.forename: Arturo
authors.initials: A
authors.lastname: Recabarren
mesh_terms: D000293:Adolescent; D000420:Albuterol / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000627:therapeutic use; D002648:Child; D018450:Disease Progression; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D004802:Eosinophilia / Q000378:metabolism; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D009573:Nitrites / Q000378:metabolism*; D011379:Prognosis; D011446:Prospective Studies; D018582:Sick Leave / Q000706:statistics & numerical data; D013183:Sputum / Q000737:chemistry
chemical_list: D001993:Bronchodilator Agents; D009573:Nitrites; D007073:Immunoglobulin E; D000420:Albuterol
keywords: asthma; children; induced sputum; nitric oxide metabolites; nitrites