560 IMMUNOLOGY 



forms of hypersensitiveness are designated by Coca as atopy. 

 Zinsser, Enders and Fothergill (1939) and Coca (1931) state that 

 two factors determine the development of atopic hypersensitive- 

 ness ; i.e., contact and the inherited capacity to become sensitized. 



Reagins Not Demonstrable in All Cases of Allerg:y. — While 

 specific antibodies, which Coca calls reagins, are present in the 

 blood of all asthma and hay fever patients who give positive skin 

 tests, speeific reagins have not been found in those suffering from 

 contact dermatitis, serum disease or drug allergy although there 

 is evidence which suggests that they, too, are mediated by an anti- 

 gen-antibody mechanism. Zinsser (1931) bases his belief that 

 all human idios^mcrasies and anaphylaxis are mediated by similar 

 if not identical mechanisms upon the following facts : The idio- 

 syncrasies are specific, are frequently accompanied by specific 

 skin reactions, are alike regardless of the kind of exciting agent 

 involved, and are often amenable to desensitization. One might 

 add also that in experimentally produced contact dermatitis, in 

 serum disease, and in many cases of drug allergy, the idiosyncrasy 

 develops after an incubation period. The assumption that anti- 

 bodies do not participate in these three types of allergy is based 

 upon negative results where passive transfer has been attempted. 

 We agree with Zinsser that such negative findings do not now 

 constitute adequate reasons for assuming a different mechanism 

 from that demonstrable for most of the atopies and for anaphy- 

 laxis. 



Loveless (1940) reports the existence of two antibodies in the 

 serum of hay-fever patients. One is the reagin and the other is 

 an antibody that binds and neutralizes the homologous antigen. 



Passive Transfer of Reagin and the P-K Reaction. — In 1919 

 Ramirez reported that a patient transfused with blood from a 

 donor sensitive to horse proteins became hjq^erscnsitive to the same 

 exciting agent. Doerr cites a number of examples of passive 

 sensitization following transfusion from allergic donors. It is 

 generally agreed, however, that such cases are extremely rare. 

 In 1921 Prausnitz and Kiistner discovered that the serum of many 

 hypersensitive individuals, when injected intradermally into a nor- 

 mal person, renders the local area injected hypersensitive to the 

 same exciting agent to which the donor is sensitive. Kiistner was 

 sensitive to fish. He demonstrated that his serum contained anti- 



