THEOPHYLLINE SUPPRESSES THE RELEASE OF INTERLEUKIN-4 BY PERIPHERAL-BLOOD MONONUCLEAR-CELLS

To elucidate the mechanism of the anti-inflammatory effect of theophyl line, peripheral blood mononuclear cells (PBMCs) collected from patien ts with bronchial asthma who had a RAST score for Dermatophagoides far inae (Df) > = 3 were stimulated with Df antigen, and the interleukin-4 , (IL-4) production by the stimulated PBMCs was determined in the pres ence and absence of theophylline. The stimulated IL-4 production in th e PBMCs was significantly suppressed by simultaneous treatment with th eophylline (8 mu g/ml). Furthermore, the intracellular 3',5'-adenosine monophosphate (cAMP) level following stimulation with Df was signific antly higher in PBMCs simultaneously treated with theophylline (8 mu g /ml than in nontreated controls. These results suggest that theophylli ne suppresses the IL-4 production in inflammatory cells by increasing the intracellular cAMP level; this effect may thus provide an addition al basis for the benefit of theophylline in antiasthmatic therapy.