Mode of action of disodium cromoglycate, studies on immediate type hypersensitivity reactions using 'double sensitization' with two antigenically distinct rat reagins.

Abstract

The mode of action of disodium cromoglycate has been investigated to determine at what stage in immediate type hypersensitivity reactions the compound is effective. In vitro studies using rat subcutaneous connective tissue sensitized with rat reagin revealed that the compound inhibited the allergic release of histamine if present during antigen challenge. The presence of the compound during sensitization had no effect on antigen-induced release of histamine provided the compound was removed prior to antigen challenge. Tissues which had undergone a primary antigen challenge in the presence of disodium cromoglycate did not release histamine when the compound was removed and the tissues rechallenged. These findings indicated that antigen/antibody interaction occurred in the presence of the compound resulting in desensitization to a subsequent antigen challenge. To corroborate the evidence of the in vitro studies in vivo passive cutaneous anaphylactic reactions (PCA) were undertaken using tissue sites sensitized with two reaginic antibodies which permitted a sequence of antigen challenges. Results from these in vivo reactions demonstrated that it was possible to desensitize tissue, without the release of the mediators of anaphylaxis, by an antigen challenge and disodium cromoglycate treatment. In these sites sensitized with two antibodies the immunological reactivity was maintained following a primary antigen challenge and disodium cromoglycate treatment, as a subsequent challenge with the dissimilar antigen produced a good PCA reaction. It would appear that disodium cromoglycate acts either directly or indirectly at a stage following antigen/antibody reaction but prior to the release of the mediators of anaphylaxis.