An anti-inflammatory steroid inhibits tissue sensitization by IgE in vivo.

An anti-inflammatory corticosteroid, dexamethasone, was found to be a potent suppressor of cell sensitization induced by IgE antibody in a model of type I allergic inflammation in vivo. Low doses (approximately less than 10(-10) mol) of dexamethasone, administered intradermally to rabbits 90 min before injection of IgE into the same sites, suppressed local oedema induced by a local challenge with antigen 72 h later. The effect was not due to anti-inflammatory activity persisting in the skin site for the 3 day period. This novel potent activity of the corticosteroid may be an important component of its anti-allergic effect in diseases such as asthma.