Inhibition of immediate hypersensitivity reactions by disodium cromoglycate. Requirements for activity in two laboratory models

The ability of disodium cromoglycate to inhibit IgE-mediated cutaneous anaphylaxis in the rat in vivo and release of histamine from peritoneal mast cells in vitro has been studied. Only when drug and antigen were presented to the sensitized cells simultaneously was a dose-dependent inhibition demonstrable. After the drug had been given alone, in the absence of antigen, either in vivo or in vitro it had little or no action when given again at antigen challenge. In vivo, this refractory state was reversible. It is suggested that disodium cromoglycate may act by releasing some factor capable of inhibiting the release of mediators from the mast cell.