Effect of slow-release theophylline on nasal antigen challenge in subjects with allergic rhinitis.

It has been recognized recently that theophylline possesses anti-inflammatory effects that could be of clinical interest in patients with airway inflammatory diseases such as asthma and allergic rhinitis (AR). The aim of the present study was to explore the effect of theophylline on the nasal eosinophilic inflammatory response following allergen challenge in patients with AR. Fourteen subjects suffering from seasonal rhinitis with an early reaction after nasal allergen provocation were challenged outside the pollen season after pretreatment for 3 weeks with placebo or slow-release theophylline (Euphylong in a randomized double-blind, cross-over study. Nasal blocking index (NBI), nasal airway resistance and symptoms were recorded before, and 1 and 5 h after challenge; additionally, nasal lavage fluid was collected before, as well as 1 and 5 h after challenge. Eosinophil cationic protein (ECP) was measured in the lavage as well as the number of eosinophils before, and 1 h and 5 h after allergen challenge. After 3 weeks of treatment, baseline concentrations of ECP in nasal lavage amounted to 826+/-329 ng x L(-1) (placebo) and 936+/-351 ng x L(-1) (theophylline). The ECP levels did not increase during the early phase response. Five hours after challenge, ECP in the placebo group increased markedly (p<0.01), whereas no significant increase was observed during theophylline treatment. In parallel, the number of eosinophils in the nasal lavage fluid was lower during theophylline treatment. Additionally, theophylline therapy also significantly reduced the nasal symptoms and had some protective effect against nasal obstruction following allergen challenge. These results confirm the anti-inflammatory effects of theophylline and suggest that these effects may be of clinical benefit in patients with allergic rhinitis.