THE IN-VITRO AND IN-VIVO EFFECT OF CORTICOSTEROIDES ON BASOPHIL RELEASABILITY IN PATIENTS WITH MILD AND SEVERE BRONCHIAL-ASTHMA

Background While inhalation of corticosteroids (CST) is considered ver y effective in most asthmatic patients, some require a high dose of or al prednisone to control the disease. Basophils, which participate in inflammation, are responsive to cortiscosteroids by suppressing histam ine release. Objectives We investigated the in vivo (oral prednisone) and in vitro (dexamethasone, DEX) effect on basophil histamine release in mild and steroid-dependent asthmatics. Methods Histamine release f rom basophils to anti-IgE and anti-IgE + IL3 was evaluated following f ive days of prednisone given 20 mg twice daily in eight subjects with mild disease and 2 h following their daily prednisone ingestion in eig ht subjects with severe disease, as well as after in vitro DEX was add ed to the cells. Results Histamine release from basophils was seen fol lowing anti-IgE as well as anti-IgE + IL-3. The same amount of release was seen in the mild and severe asthmatics. In vivo prednisone suppre ssed histamine release to both stimuli and DEX added to the suppressio n in the mild asthmatics, In the severe ones, DEX showed no inhibitory effect on histamine release. Conclusion Oral and in-vitro CST suppres sed histamine release from basophils of mild but not severe CST-depend ent asthmatics. Suppression of basophil releasability can be a reflect ion of asthma severity.