ANAPHYLAXIS

Abstract

The evidence may be considered conclusive that a tissue liberation of histamine, of heparin, and possibly of choline occurs during the anaphylactic reaction in various animals. In the dog the liberation of heparin can completely account for the incoagulability of the blood and there is no reason to doubt that it may be found in other animals. There is no evidence that it is responsible for any of the other dominant symptoms as large amte. of heparin can be injd. into animals without harm. The liberation of histamine can account for practically all of the other effects and there is no well defined prominent symptom demanding an alternative explanation. Such changes as loss of complement, etc., are excluded from this statement and may be considered as being related to the antigen-antibody reaction per se. The observations of Went suggest that choline may participate in the reaction in the guinea pig and possibly of course in other animals, although further evidence is necessary to establish this. The leukopenia in all animals can be explained by the mechanisms described by Abell and Schenk in the rabbit, and it is probable that leukocytic emboli may contribute more or less to the vascular reactions produced by histamine. For animals other than the dog, guinea pig and rabbit decisive evidence is lacking, but the symptomatology is nowhere incompatible with the conclusion that similar reactions take place. The cardinal symptoms of anaphylaxis can thus be explained as being due, in the immediate instance, to an autointoxication by physiologically active substances normally resident in various tissue cells and liberated therefrom by some change in cellular permeability brought about by the antigen-antibody reaction. It is apparent that the tissues concerned may be either the fixed tissues as in the dog or guinea pig, or the circulating tissue as in the rabbit. It is also apparent that the ractions mediated by these anaphylatoxins may occur in the tissues from which they were liberated or in distant organs and tissues.