title: Maximal airway response in adolescents with long-term asthma remission and persisting airway hypersensitivity: its profile and the effect of inhaled corticosteroids.
abstract: BACKGROUND
  Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in some of these subjects. BHR in asthma is characterized by an increase in sensitivity and in maximal airway response to bronchoconstrictor stimuli.
  
  
  OBJECTIVE
  The aims of this study were to compare the profiles of maximal airway response between adolescents with asthma remission and adolescents with symptomatic asthma to a similar degree of airway hypersensitivity, and to determine whether maximal airway response in adolescents with asthma remission is reduced by prolonged treatment with inhaled corticosteroids.
  
  
  METHODS
  A high-dose methacholine inhalation test was performed in 46 adolescents with long-term asthma remission (remission group) and 44 adolescents with symptomatic asthma (symptomatic group). Subjects exhibiting a maximal response plateau in the remission group were administered inhaled budesonide (400 microg bid, budesonide/remission group, n = 15) or identical placebo (placebo/remission group, n = 15) for 6 months, and the subjects in the symptomatic group were administered the same regimen of budesonide (budesonide/symptomatic group, n = 17). The plateau level was measured after 3 months and 6 months of treatment.
  
  
  RESULTS
  Thirty-four subjects (73.9%) in the remission group featured a maximal response plateau on the dose-response curve to methacholine, whereas 19 subjects (43.2%) in the symptomatic group had a plateau (p = 0.003). In neither the placebo/remission group nor the budesonide/remission group did the plateau level change significantly over the 6-month period, whereas budesonide markedly decreased the level in the budesonide/symptomatic group.
  
  
  CONCLUSIONS
  The difference in frequency of detection of a plateau between the remission group and the symptomatic group, as well as the difference in its response to treatment with budesonide between the two groups, suggests that inflammatory changes impact the maximal airway response in symptomatic asthmatic adolescents but not in adolescents with asthma remission.
authors.affiliation: Department of Pediatrics, Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea. kohyy@plaza.snu.ac.kr
authors.forename: Young Yull
authors.initials: YY
authors.lastname: Koh
authors.forename: Yang
authors.initials: Y
authors.lastname: Park
authors.forename: Chang Keun
authors.initials: CK
authors.lastname: Kim
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000402:Airway Obstruction / Q000175:diagnosis / Q000188:drug therapy; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000188:drug therapy*; D001985:Bronchial Provocation Tests; D019819:Budesonide / Q000008:administration & dosage*; D016022:Case-Control Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D011336:Probability; D011379:Prognosis; D012016:Reference Values; D012075:Remission, Spontaneous; D012129:Respiratory Function Tests; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
chemical_list: D000305:Adrenal Cortex Hormones; D016210:Methacholine Chloride; D019819:Budesonide