The role of the adrenergic system in allergy and bronchial hyperreactivity

The adrenergic system may have an influence on the severity and activity of bronchial asthma. It has been suggested that there might be a relationship between the allergic process and the adrenergic system. Therefore this system was studied before and after an allergen challenge. Two parameters were measured: in vivo: propranolol threshold measurement to assess adrenergic involvement; in vitro: the beta-adrenergic response of peripheral lymphocytes as parameter for beta-receptor function. Seven allergic asthmatics who were not treated with beta-stimulants or corticosteroids and seven normals inhaled house dust mite extract. On the days before and after the challenge, propranolol threshold measurements were performed. Six patients had a dual reaction after a house dust mite inhalation; one patient had an early response. The propranolol threshold changed from 1.32% (SEM 0.16) on the day before challenge to 0.86% (SEM 0.19) on the day after (0.02 less than P less than 0.025). In the same patients the maximal cAMP response of lymphocytes in the presence of 10(-6) mM isoproterenol changed from 339% (SEM 18.9) above basal level before the allergen challenge to 194% (SEM 24.6) after the challenge (0.001 less than P less than 0.005). The pre-challenge beta-response of lymphocytes of the asthmatic patients was comparable with that of normal lymphocytes (298% SEM 59.8). The results suggest that an allergen-induced asthmatic attack may lead to an impaired beta-adrenergic function.