Magnitude and site of airway response to exercise in asthmatics in relation to arterial histamine levels

Abstract

In order to determine if there is a relationship among arterial histamine levels, state of disease activity, and the magnitude and site of obstruction in exercise-induced asthma, we recorded airway resistance, lung volumes, spirometry, and density dependence of maximum expiratory flow before and after an exercise challenge in 17 asymptomatic individuals. These observations were then related to the concentration of histamine in systemic arterial blood. This study demonstrates that those individuals whose disease process was the most active at the time of investigation had more depressed lung function and higher baseline histamine levels, and responded to the challenge with severe obstruction that involved the airways in the periphery of the lung. In contrast, those subjects whose underlying disease was more quiescent had lower histamine values and the response to provocation was less severe and predominated in the larger airways. In neither group did the postchallenge values for histamine increase. It is suggested that the factor that determines these patterns of response is the state of inflammation of the airways, for which histamine may serve as a marker.