Asthma and airway inflammation: potential anti-inflammatory activities of phosphodiesterase inhibitors.

Asthma is now recognized as an inflammatory disease associated with eosinophil infiltration into the pulmonary tissue. It has appeared in recent years that phosphodiesterase type IV inhibitors presented all the necessary characteristics to be used as new anti-asthmatic drugs. Indeed, in addition to their bronchodilator properties, they have inhibitory activities on inflammatory cell infiltration into the lung and on inflammatory mediator release. However, the mechanism of action of phosphodiesterase inhibitors, theoretically linked to the increase in intracellular cAMP, is now largely open for discussion.