The in vitro and in vivo effect of corticosteroides on basophil releasability in patients with mild and severe bronchial asthma

Summary Background While inhalation of corticosteroids (CST) is considered very effective in most asthmatic patients, some require a high dose of orul prcdnisonc to control the disease. Basophils, which participate in inflammation, are responsive to cortiseosteroids by suppressing histamine 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 from basophils to anti-IgE and anti-IgE + IL3 was evaluated following live days of prednisone given 20 mg twice daily in eight subjects with mild disease and 2 h following their daily prednisone ingestion in eight subjects with severe disease, as well as after in vitro DEX was added to the cells. Results Histamine release from basophils was seen following 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 suppressed histamine release to both stimuli and DEX added to the suppression in the mild asthmatics. In the severe ones. DEX showed no inhibitory effect on histamine release. Conclusion Oral and in-vitro CST suppressed histamine release from basophils of mild but not severe CST-dependent asthmatics. Suppression of basophil releasability can be a reflection of asthma severity.