BRONCHIAL REACTIVITIES IN ASTHMATIC SUBJECTS AFTER LONG TERM REMISSION

Abstract

It is not known if asthmatics represent a separate hyperreactive population from the normal distribution of airways reactivity (AR),or if they merely represent a hyperreactive extreme of a normal distribution.In a recent study about AR (Lancet ii,792, 1983) our findings suggested the first hypothesis:this may imply that “once asthmatic, always an asthmatic”. On these assumptions,we studied the bronchial reactivity to Carbacholine in 12 subjects with a remote hystory of wheezy bronchitis during childhood,and since then free of asthma or wheezing for,at least,10 years (x 21.2 years). Stepped doses of Carbachol Cloride (0.1%) aerosol (Bronchotest,Dr.J.Piglowsky,Paris)were given until a 50% drop in forced expiratory flow at 25-75% was observed, or until the subject had inhaled 80 times his own forced vital capacity equivalent of the aerosol.All 12 patients were found to have AR in the asthmatic range (data obteined in 50 asthmatics).The persistence of bronchial hyperreactivity during long term symptom free periods,implies that bronchial hyperreactivity may be a constitutional inherited character which may become clinically manifest if the subjects are exposed to exogenous factors such as environmental irritants (no one of our patients had an occupational risk),infectious agents,or allergens,even after subsidence of asthma symptoms for many years.The lowest values in the asthmatic range were observed in our patients with at least an allergy skin prick test positive (a weal 3 mm or more in diameter)or smokers.It is possible that if these risk factors had been present in those subjects with greatly increased non specific AR,they would have been asthmatic.