Effects of theophylline compared with prednisolone on late phase airway leukocyte infiltration in guinea pigs.

The effects of prednisolone, theophylline or salbutamol treatment were studied on leukocyte numbers in bronchoalveolar lavage (BAL) fluid taken 72 h after ovalbumin challenge in sensitized guinea pigs. Ovalbumin challenge resulted in an approximate 3-fold increase in the number of eosinophils in BAL fluid. This increase was significantly reduced by oral administration of prednisolone (59% inhibition with 10 mg/kg x 2) theophylline (56% with 50 mg/kg x 2) but not by salbutamol (10 mg/kg x 2). A comparison with the bronchodilator potency of the above drugs indicated that in guinea pigs salbutamol appears relatively selective as a bronchodilator, prednisolone is selective as an inhibitor of eosinophilia whilst theophylline displays a balance of both activities.