111 years of allergen-immunotherapy: A long and successful history of the only available disease-modifier in allergic diseases

The great milestones in medicine almost always have their precursors, which help the great event to break through. So it was with allergen-specific immunotherapy (AIT) and the great work of Noon and Freeman and their world-renowned publication in 1911. In this article, we want to outline AIT's long journey, from early attempts to achieve tolerance to allergens in the environment. Many very different methods were used; from homeopathy to the use of recombinant allergens. Initially, the allergen extracts were given only subcutaneously, but then also through other routes, such as nasal, rectal, intradermal, epicutaneous, in lymph nodes, or oral. It was the great merit of Bill Franklin, whom many of us still experienced as active participants in congresses, to point out that the effect of AIT must be documented not only by clinical observation but in a controlled form including placebo injections. AIT was thus transferred to evidence-based medicine, which we successfully apply today. We would like to express our gratitude to Bill Franklin himself and all others involved in the development of AIT with this summary of 111 years of immunotherapy.