title: Leukotriene D4 and methacholine bronchial provocation tests for identifying leukotriene-responsiveness subtypes.
abstract: BACKGROUND
  Both leukotriene D(4) (LTD(4)) and methacholine bronchial provocation tests are measurements of airway responsiveness; however, their correlation and distinction remain unexplored.
  
  
  OBJECTIVE
  We sought to compare the 2 tests and classify leukotriene-responsiveness subtypes in asthmatic patients.
  
  
  METHODS
  In this randomized cross-over study we enrolled healthy subjects and asthmatic patients with different control statuses. All subjects underwent both tests with a 2- to 14-day interval. Distribution and correlation of cumulative doses inducing a 20% decrease in FEV(1), LTD(4)/methacholine potency ratio, diagnostic value, and adverse events were recorded and analyzed. Asthmatic patients with a lower cumulative dose for LTD(4) and a higher leukotriene/methacholine potency ratio than geometric means were regarded as leukotriene responsive.
  
  
  RESULTS
  Twenty patients with uncontrolled, 22 with partly controlled, and 20 with controlled asthma and 21 healthy subjects were enrolled. Geometric means of cumulative doses for LTD(4) and methacholine (0.272 nmol vs 0.945 μmol) were lowest in patients with uncontrolled asthma, followed by those with partly controlled (0.387 nmol vs 1.933 μmol) and controlled (1.484 nmol vs 3.946 μmol) asthma. The average potency ratio was highest in those with partly controlled asthma (5000.2), followed by those with uncontrolled (3477.7) and controlled (2702.6) asthma. Eighteen leukotriene-responsive asthmatic patients (29.03%) with a cumulative dose of LTD(4) of 0.533 nmol or less and a potency ratio of 3647 or greater were identified. Adverse events, including tachypnea and chest tightness, were similar and mild. No serious adverse event was reported.
  
  
  CONCLUSIONS
  Diagnostic value and safety were ideal in both tests. The combination of cumulative dose for LTD(4) and potency ratio might be useful to identify leukotriene-responsive asthmatic patients.
authors.affiliation: State Key Laboratory of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical College, Guangzhou, China.
authors.forename: Weijie
authors.initials: W
authors.lastname: Guan
authors.forename: Jinping
authors.initials: J
authors.lastname: Zheng
authors.forename: Yi
authors.initials: Y
authors.lastname: Gao
authors.forename: Caiyu
authors.initials: C
authors.lastname: Jiang
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Xie
authors.forename: Jiaying
authors.initials: J
authors.lastname: An
authors.forename: Xinxin
authors.initials: X
authors.lastname: Yu
authors.forename: Wenting
authors.initials: W
authors.lastname: Liu
authors.forename: Nanshan
authors.initials: N
authors.lastname: Zhong
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D001249:Asthma / Q000175:diagnosis*; D001980:Bronchi / Q000187:drug effects*; D001985:Bronchial Provocation Tests / Q000379:methods*; D016022:Case-Control Studies; D018592:Cross-Over Studies; D006801:Humans; D017998:Leukotriene D4 / Q000008:administration & dosage / Q000009:adverse effects; D016210:Methacholine Chloride / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D016210:Methacholine Chloride; D017998:Leukotriene D4