988 ANAPHYLAXIS AND ANAPHYLACTOID REACTIONS 



RELATION OF ANAPHYLAXIS AND ANAPHYLACTOID REACTIONS 



Hanzlik supports the idea that the two phenomena have a common basis. The 

 resemblance in the symptoms and the chemical and physical changes in the blood are 

 offered as evidence. The fact that smooth-muscle stimulation is not common to the 

 anaphylactoid reactions is explained by the fact that most of the agents are of large 

 molecular constitution which leads "to a lack of suitable conditions enabhng them to 

 diffuse into and penetrate the cell surface and react with the muscle substance," 

 Hanzlik ascribes the differences in gross and microscopical morbid anatomy to differ- 

 ence in degree of the same phenomena. 



Against this hypothesis it may be pointed out that the symptoms, in some ways 

 identical, differ in important ways. In the guinea pig, for example, death in ana- 

 phylactic shock is practically invariably respiratory, while in anaphylactoid reactions 

 it is commonly circulatory. The physical and chemical changes in the blood in true 

 anaphylactic shock have not been so well studied as in anaphylactoid reactions, and 

 unfortunately those observed in the latter have been assumed to occur in the former. 

 Accepting Hanzlik's explanation of the failure of smooth-muscle reactions in response 

 to many of the anaphylactoid agents, it is presumably safe to say that the reaction 

 in anaphylaxis is within the cell and probably not a surface phenomenon. 



Anaphylactoid reactions are for the most part obviously in the circulating fluids, 

 operating secondarily upon various body mechanisms, whereas the reaction in ana- 

 phylaxis is independent of changes in the circulating fluids. Against this hypothesis 

 are some of the physical theories of anaphylaxis, which in accordance with our discus- 

 sion of the matter are not adequately supported. 



It is true that anaphylaxis and the various anaphylactoid reactions can be set 

 side by side and arranged in a series so that there might seem to be a gradation from 

 true anaphylaxis through closely similar anaphylactoid reactions to those that diverge 

 widely from true anaphylaxis. No such presentation can overcome the fact that 

 anaphylaxis is an antigen-antibody reaction and that anaphylactoid reactions are 

 not. 



