The Preventive Effect of Anti-Allergic Drugs and the Change in Migrated Cells in Nasal Lavage Fluid in Japanese Cedar Pollinosis.

The patients with Japanese Cedar Pollinosis registered in 1993 were divided to either the preventive dosing group or the therapeutic dosing group. Various migrated cells in nasal lavage fluid collected during the season were measured, and the clinical symptoms and onset dates were compared between the two groups. The preventive dosing group started to take Oxatomide more than 4 weeks before the beginning of pollen scattering, whereas the therapeutic dosing group started to take this drug in a similar manner after pollen began to scatter and after symptoms developed. The preventive dosing group showed a significant inhibition of total subjective symptoms early in the season as compared with the therapeutic dosing group. At the same time, the preventive treatment significantly delayed the onset of clinical symptoms. There were no remarkable changes in eosinophils and CD68 positive cells in nasal lavage early in the season in the preventive dosing group, whereas neutrophils and eosinophil cationic protein (ECP) showed a significant decrease. From these result, we conclude that starting to take anti-allergic drugs more than 4 weeks before the beginning of pollen scattering can inhibit clinical symptoms early in the season and also delay the onset of symptoms in a year predicted to have a great quantity of cedar pollen scattering.