Inhibitory effects of theophylline and procaterol on eosinophil function

Eosinophils play a crucial role in bronchial asthma. As theophylline and procaterol (beta 2-agonist) are used for the treatment of bronchial asthma, the specific functions of eosinophils in the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF) or platelet activating factor (PAF) were examined using theophylline and procaterol alone and in combination. Eosinophil degranulation induced by PAF or GM-CSF was inhibited by theophylline (10(-6) M-10(-3) M and 10(-6) M to 10(-3) M, respectively) and procaterol (10(-7) M-10(-5) M and 10(-7) M-10(-5) M, respectively). The combination of 10(-4) M theophylline and various concentrations of procaterol provided higher inhibition than 10(-4) M theophylline or procaterol (10(-7) M-10(-5) M). CD11b, which is a triggering molecule for human eosinophil degranulation, showed a significantly inhibited expression of PAF stimulation with 10(-4) M theophylline. CD11b and another triggering molecule for eosinophil degranulation, CD18, showed a significantly inhibited expression of PAF stimulation using a combination of 10(-4) M theophylline and various concentrations of procaterol (10(-5) M-10(-7) M) compared with the inhibition of 10(-4) M theophylline or procaterol (10(-5) M-10(-7) M), but GM-CSF-stimulated eosinophils were not inhibited. Taken collectively, theophylline and/or procaterol have anti-inflammatory effects.