Clemens von Pirquet
Munchen Med Wehnscher 1906
In the course of the last few years a number of facts have been collected which belong to the domain of Immunology but fit poorly into its framework. They are the findings of supersensitivity in the immunized organism. These two terms clash with each other. Do we not regard an organism as immune if it is protected against the disease, is not attacked by it a second time? How can this organism at the same time be supersensitive to the same disease?….these two terms contradict each other; their union is a forced one. In fact, the concept of immunity has been carried on since a time when supersensitivity was unknown… What we need is a new generalized term, which prejudices nothing but expresses the change in condition, which an animal experiences after contact with any organic poison, be it animate or inanimate. The vaccinated person behaves towards vaccine lymph, the syphilitic towards the virus of syphilis, the tuberculous patient towards tuberculin, the person injected with serum towards this serum, in a different manner from him who has not previously been in contact with such an agent. Yet he is not sensitive to it. We can only say of him that his power to react has undergone a change. For this general concept of a changed reactivity I propose the term Allergy. “Allos” implies deviation from the original state, from the behavior of the normal individual, as it is used in the words Allorhythmia, Allotropism. The vaccinated, the tuberculous, the individual injected with serum becomes allergic towards the corresponding foreign substance. A foreign substance, which by one or more application stimulates the organism to a change in reaction is an Allergen.
From Landmark Papers in Allergy: Seminal Papers in Allergy with Expert Commentaries Stephen Holgate, Aziz Sheikh, Tom Platt-Mills, and Allison Worth. Oxford University Press, Oxford 2013