Inhibition of basophil histamine release by anti-inflammatory steroids

Abstract

The release of histamine from human leukocytes is a useful in vitro model for studying allergic disease¹. Many of the drugs used in the treatment of allergy and asthma (for example, isoprenaline and theophylline) are effective inhibitors of in vitro histamine release². However, the anti-inflammatory steroids have not been found to inhibit the in vitro release of histamine from mast cells or basophils activated by immunological stimuli^3–6. In view of the fact that the in vivo anti-allergic effects of steroids occur only 12‐24 h after administration⁷, we have re-examined the effects of these drugs on IgE-mediated histamine release from human basophils after prolonged incubations. We report here a time-dependent inhibition of histamine release from human basophils by glucocortico-steroids. The relative activity of a series of steroids as inhibitors of histamine release correlates well with the relative in vivo anti-inflammatory activity of the same compounds. These results suggest that the basophil may be an in vivo target of the anti-inflammatory steroids and that inhibition of this cell type may account for some of the activity of steroids in preventing inflammation.