Increase in airway responsiveness and effect of deep inhalation on airway caliber in allergen-induced asthma. Relationship to the late-phase response

Am Rev Respir Dis. 1992 Jul;146(1):127-31. doi: 10.1164/ajrccm/146.1.127.


The airway responsiveness to methacholine (MCh) and the effect of deep inhalation (DI) on airway caliber were determined in 18 asthmatic patients at baseline and 3 and 24 h after an allergen inhalation challenge. The dose of MCh causing a 20% fall of FEV1 (PD20) was used as an index of airway responsiveness; the ratio of forced expiratory flow at 40% of FVC from maximal and partial flow/volume curves (MEF40M/P) was used to assess the effect of DI on airway caliber. Thirteen patients showed a dual asthmatic response (DAR) to allergen, 5 patients an isolated early-phase asthmatic response (EAR). In the DAR patients, 3 h after allergen challenge, when the early-phase response had resolved and the late-phase response had yet to develop, MChPD20 (geometric mean) was reduced from 202 to 71 micrograms (P less than 0.001) whereas MEF40M/P at the MCh end point was unchanged (p greater than 0.4). Twenty-four hours after allergen challenge, when late-phase response had developed, MChPD20 was further reduced to 51 micrograms (p less than 0.02), and this reduction was accompanied by a decrease of MEF40M/P at the MCh end point (p less than 0.01). In the EAR patients, neither MChPD20 nor MEF40M/P was significantly changed at any time during the study. We conclude that most of the increase in airway responsiveness that follows acute exposure to allergen precedes the late-phase response and is not determined by the same mechanisms that impair the ability of the lung to dilate airways with a DI.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Allergens / administration & dosage*
  • Asthma / physiopathology*
  • Bronchi / physiopathology*
  • Bronchial Provocation Tests
  • Forced Expiratory Flow Rates
  • Forced Expiratory Volume
  • Humans
  • Methacholine Chloride
  • Middle Aged
  • Time Factors


  • Allergens
  • Methacholine Chloride