[Bronchial hyperreactivity in 1994, a cheerful quinquagenarian. Conclusions]

A review is made of the principal themes that are discussed in this supplement of the Revue des Maladies Respiratoires. Three important questions on bronchial hyperresponsiveness, a key feature of asthma, are raised: 1) the clinical usefulness of its assessment, mostly in the atypical forms of asthma and in occupational asthma and, less so, to estimate the severity of asthma; data derived from the Bayesian analysis lead to the conclusion that it is a test which is better for excluding rather than for confirming asthma; in an epidemiological setting, the assessment of bronchial responsiveness should be carried out to assess both host factors and the effect of environmental exposure; 2) the method of assessment which should take into account the stimulus, be it pharmacological or not, the physiological index used to assess the response and the mode of expression of results; 3) finally, the mechanisms of bronchial responsiveness are probably multiple as examined in different chapters of this supplement.