Charles Richet: The Discoverer of Anaphylaxis and Founder of Allergy Science (1913)

Nobel Information Card

• Award Year: 1913
• Field: Physiology or Medicine
• Award Rationale: For his work on anaphylaxis.
• Birth: 25 August 1850, Paris, France
• Death: 4 December 1935, Paris, France
• Nationality: French
• Institution: University of Paris Faculty of Medicine

Life and Education

Charles Robert Richet was born in Paris on August 25, 1850. His father, Alfred Richet, was a respected surgeon at the University of Paris Faculty of Medicine, holding a chair in clinical surgery. His mother, Eugénie Renouard, came from a cultured bourgeois family. Growing up in an intellectual environment where medicine was a family tradition, Richet developed an interest in both science and literature from an early age. His father allowed him to get close to the hospital environment, which played a decisive role in his decision to pursue a career in medicine.

Richet completed his secondary education at the prestigious Lycée Bonaparte in Paris (now Lycée Condorcet). He enrolled at the University of Paris Faculty of Medicine in 1869. During his medical studies, the Franco-Prussian War (1870-1871) broke out, and young Richet volunteered for ambulance service during the Siege of Paris. This experience led him to witness firsthand the devastating effects of war and later influenced his advocacy for the peace movement.

Richet, who earned his medical degree from the University of Paris in 1877, began his career in physiology at the same university. He became a professor of physiology at the Paris Faculty of Medicine in 1887 and held this position for over forty years. Richet was an extraordinary polymath with interests spanning a wide range of fields. In addition to his physiological research, he actively pursued literature, aviation, pacifism, and even parapsychology.

The personal life of Richet was rich and multifaceted. He married Amélie Aubry in 1877 and had five children from this marriage. Richet was an active member of Paris's intellectual circles. He wrote plays and novels, experienced aviation adventures, and played an active role in the peace movement. This versatility made him one of the most colorful scientists of his time.

Scientific Work

Charles Richet's scientific career is characterized by extensive work across a wide range of subfields of physiology. Prior to his discovery of anaphylaxis, he conducted significant research in thermoregulation, digestive physiology, serology, and neurophysiology. He studied the chemical composition of gastric secretions, investigated the therapeutic potential of animal sera, and conducted studies on muscle physiology.

Richet's journey to discover anaphylaxis began with research into the physiological effects of sea nettle and jellyfish venoms. In 1901, he accepted an invitation from Prince Albert II of Monaco to join a scientific expedition aboard the prince's yacht in the Mediterranean. During this voyage, Richet and physiologist Paul Portier studied the effects of the Physalia (Portuguese man-of-war) jellyfish venom on dogs. They injected various doses of the venom into the animals to determine its toxic dose.

When they returned to Paris, Richet and Portier continued their experiments using extracts from the venom of sea scorpions (the toxins). Their goal was to test whether low doses of toxin injections could induce an immune response in animals. They expected that the initial injection would either confer tolerance or immunity against the venom in animals, which was the fundamental principle behind serum therapy.

The results, however, were the opposite of expectations. When dogs that had received the initial injection without any issues were given a second low dose of the toxin several weeks later, they developed severe reactions. Blood pressure plummeted dramatically, breathing became labored, vomiting and diarrhea began, and some animals died within minutes. Although the first dose appeared harmless, the second dose triggered a fatal hypersensitivity reaction.

Discovery Leading to the Nobel Prize

Richet quickly grasped this unexpected finding and recognized its scientific significance. The phenomenon he observed was the opposite of immunity (prophylaxis): instead of becoming more resistant to toxins after initial exposure, the organism became more sensitive. Richet named this phenomenon anaphylaxis, deriving it from the Greek words "ana" (against, opposite) and "phylaxis" (protection), giving it the meaning of the opposite of protection.

In 1902, Richet and Portier published their first scientific paper on anaphylaxis. This article is considered one of the most important publications in the history of immunology. Richet identified the fundamental characteristics of anaphylaxis: the need for an incubation period between the first exposure and second exposure, that even low doses of the second exposure can be fatal, and that the reaction develops very quickly.

To elucidate the mechanism of anaphylaxis, Richet conducted extensive experiments. He showed that the initial injection caused a change in the organism and that this change led to hypersensitivity to the second injection after a certain period. He demonstrated that the anaphylactic reaction was specific: the animal became sensitized only to the toxin it had been previously exposed to, continuing to respond normally to different toxins. This specificity suggested that the reaction was based on an immunological mechanism.

Richet also demonstrated that passive anaphylaxis was possible: by transferring the serum from a sensitized animal to a normal one, the recipient animal could exhibit anaphylactic reactions as well. This finding proved that anaphylaxis was due to a humoral factor (found in the blood serum). Today, this factor is known to be IgE antibodies.

The discovery of anaphylaxis revealed for the first time that the immune system is capable not only of protective but also of harmful responses. This finding led to the birth of the modern concepts of allergy and hypersensitivity. Anaphylaxis showed that the immune system, although a remarkable defense mechanism, could sometimes turn against the body itself.

The work of Richet expanded rapidly with contributions from other researchers. Clemens von Pirquet introduced the concept of allergy and linked serum sickness to anaphylaxis. Arthur Arthus identified local anaphylactic reactions (the Arthus phenomenon). These studies together formed the basis for classifying hypersensitivity reactions.

The Prize and Its Aftermath

In 1913, the Nobel Prize in Physiology or Medicine was awarded to Charles Richet for his work on anaphylaxis. Richet received the award in person at the ceremony in Stockholm. In his Nobel lecture, he described the discovery process of anaphylaxis and highlighted its profound significance for immunology. While explaining how an unexpected observation changed the fundamental understanding of medicine, he emphasized the importance of serendipity (fortunate discovery) in science.

After receiving the Nobel Prize, Richet devoted more time to his interests beyond physiology research, including advocating for the peace movement and drawing attention to the scientific and humanitarian costs of World War I. He further emphasized his pacifist views after the war.

Richet's non-scientific interests included parapsychology and spiritualism. His interest in these areas sparked severe criticism from the positivist scientific community. Richet argued that he applied scientific methods to this field, which he called meta-physical, but his efforts were generally not accepted. He also conducted experiments in aviation and believed in the future of airships (flying machines).

Charles Richet passed away at the age of eighty-five in Paris on December 4, 1935. After a long and productive life, he left his mark on history as a scientist who made one of the fundamental discoveries in modern immunology.

Legacy and Impact Today

The discovery by Charles Richet of anaphylaxis forms the foundation for modern allergy and immunology sciences. Anaphylaxis is currently considered one of the most serious conditions in emergency medicine. Food allergies, drug allergies, insect sting allergies, and latex allergy are among the most common causes of anaphylactic reactions. The epinephrine auto-injector (EpiPen) has become a lifesaving tool for millions of individuals with allergies.

The discovery by Charles Richet has created a paradigm shift in understanding allergic diseases. The elucidation of the mechanism behind IgE-mediated hypersensitivity reactions has led to significant advances in the treatment of conditions such as asthma, allergic rhinitis, atopic dermatitis, and food allergies. Anti-IgE treatments (such as omalizumab) and allergen immunotherapy are modern medical applications of Richet's discovery.

Classification of hypersensitivity reactions (Gell and Coombs classification) is a product of the scientific tradition that began with Richet's anaphylaxis studies. It defines Type I (anaphylactic), Type II (cytotoxic), Type III (immune complex) and Type IV (delayed type) hypersensitivity reactions, which form the basis of clinical immunology.

The concept that the immune system can produce harmful reactions has also laid the groundwork for understanding autoimmune diseases. Conditions such as rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and type 1 diabetes are all the result of the immune system attacking the body's own tissues.

Lesser-Known Facts

• Richet discovered anaphylaxis by accident during an experiment with sea-anemone venom. His aim was to immunize the animals against the toxin, but he obtained the very opposite. This is one of the most famous instances of serendipity in the history of science.
• The word anaphylaxis was coined by Richet to mean "against protection" or the opposite of protection. The name emphasized that the phenomenon was the antithesis of immunity (prophylaxis).
• Beyond being a scientist, Richet was also a man of letters, a playwright, and a novelist. He published many theatrical works and novels, some of which were staged in Paris.
• Richet carried out flight experiments in the early days of aviation. He designed a motor-powered flying machine, but never achieved a successful flight.
• His interest in parapsychology and spiritualism cast a shadow over his scientific career. Richet believed it was possible to study this field scientifically, but this view was not widely accepted.
• Richet was an ardent advocate of peace. He believed that war was the greatest calamity to befall humanity and played an active role in the international peace movement.
• Richet's discovery took place at the intersection of marine biology and medicine. The research, which began during a scientific expedition in the Mediterranean, led to the discovery of one of medicine's most fundamental concepts.