Jellyfishes and dogs: sleuthing allergies

It took many steps to arrive at the understanding of allergy we share today. As in every knowledge-driven process, experiments that failed were essential. They helped to uncover assumptions that were too general and needed further discrimination to be exact. With the principles of vaccination understood, the mechanism seemed to offer a remedy against a lot of threats to human health. However, as this video shows, researchers underestimated how complex the mechanisms were. In this sense dogs dying from vaccination that led to the discovery of anaphylaxis and hypersensitivity were further stepping stones to grasp allergy as a concept. For a comprehensive sketch of all the anaphylactic symptoms, please look at this graph.

The term ‘allergy’ was coined only some years later. Clemens von Pirquet, director of the Children’s Hospital in Vienna, used antisera (or ‘antitoxins’) produced in horses to treat diphtheria. For the first time, doctors could administer an effective therapy by passive immunisation and save the lives of many of their young patients. However, in some of them, 5 to 10 days after the first infusion, symptoms distinct of diphtheria occurred: fever, urticarial rashes, joint pain, and swellings. If infused again, the patients reacted again with the same symptoms, this time just after a few minutes or hours. In 1905, Clemens von Pirquet published his observations and called this new phenomenon ‘serum sickness’ – a clinical term that has survived until modern times. One year later, von Pirquet described the altered state of immunity in these patients in a short article. He coined the term ‘allergy’, composed of the ancient Greek words ‘allos’ (= altered) and ‘ergos’ (= activity). It is nowadays established as an umbrella term for all types of hypersensitivity reactions with an immunological background. In this article you can learn more about evolving concepts of allergy. Can you think of further substances causing a hypersensitivity reaction or even an anaphylactic shock? Please leave a comment below.