title: Bronchodilator responses after methacholine and adenosine 5'-monophosphate (AMP) challenges in children with asthma: their relationships with eosinophil markers.
abstract: BACKGROUND
  Bronchodilator responsiveness (BDR) and eosinophilic inflammation are characteristic features of asthma. Objective. The aim of this study was to compare the relationships of BDR after methacholine challenge or adenosine 5'-monophosphate (AMP) challenge to blood eosinophil markers in children with asthma.
  
  
  METHODS
  Methacholine and AMP challenges were performed on 69 children with mild intermittent to moderate persistent asthma. BDR was calculated as the change in forced expiratory volume in 1 second, expressed as percentage change of the value immediately after the each challenge and the value after inhalation of salbutamol. Serum total IgE levels, blood eosinophil counts, and serum eosinophil cationic protein (ECP) levels were determined for each subject.
  
  
  RESULTS
  A positive relationship between serum total IgE levels and BDR was found only after the AMP challenge (R(2) = 0.345, p = .001) rather than after the methacholine challenge (R(2) = 0.007, p = .495). Peripheral blood eosinophil counts correlated more significantly with BDR after AMP challenge (R(2) = 0.212, p = .001) than BDR after methacholine challenge (R(2) = 0.002, p = .724). Both BDR after methacholine challenge (R(2) = 0.063, p = .038) and BDR after AMP challenge (R(2) = 0.192, p = .001) were significantly correlated with serum ECP levels.
  
  
  CONCLUSIONS
  BDR after AMP challenge may be more closely related to eosinophilic inflammation, compared with that after methacholine challenge.
authors: Department of Pediatrics, College of Medicine, Korea University, Seoul, Korea. yoolina@korea.ac.kr
authors: Young
authors: Y
authors: Yoo
authors: Sung Chul
authors: SC
authors: Seo
authors: Young Il
authors: YI
authors: Kim
authors: Bo Hyun
authors: BH
authors: Chung
authors: Dae Jin
authors: DJ
authors: Song
authors: Ji Tae
authors: JT
authors: Choung
mesh_terms: D000249:Adenosine Monophosphate; D000293:Adolescent; D001249:Asthma / Q000097:blood / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D002648:Child; D047150:Eosinophil Cationic Protein / Q000097:blood; D004804:Eosinophils / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D016210:Methacholine Chloride
chemical_list: D016210:Methacholine Chloride; D000249:Adenosine Monophosphate; D047150:Eosinophil Cationic Protein