Charles Robert Richet

Charles Robert Richet (1850-1935), French physiologist and Nobel laureate who identified the immune-system response known as anaphylaxis, or anaphylactic shock. This rare allergic reaction (see Allergy) occurs in some individuals after two or three exposures to a foreign substance, or allergen, such as pollen, bee venom, medicines, or even foods such as shellfish. For his observations of anaphylaxis, summarized in a 1911 publication, Richet received the 1913 Nobel Prize in physiology or medicine.

Born in Paris, Richet studied medicine at the University of Paris, receiving his M.D. degree in 1877 and his Ph.D. degree in medicine the next year. Deciding to concentrate on medical research rather than on clinical practice, Richet was appointed professor at the Faculty of Medicine at the University of Paris in 1878. In his early research, he investigated many physiological processes (see Physiology), including digestion (see Digestive System) and muscle contraction.

Toward the end of the 1880s Richet turned his research toward the development of a serum that would stimulate the body's immune system to fight tuberculosis, a contagious bacterial disease that primarily affects the lungs. This work proved unsuccessful, but Richet's interest in immune response led him to study the poison contained in the tentacles of the Portuguese man-of-war and, later, in the sea anemone. Injecting these toxins into laboratory animals, Richet observed that some animals would survive a first injection containing high doses of toxin. However, when they received a second, smaller dose, these same animals would quickly suffer violent, fatal reactions. Richet noted that the immune systems in these animals, following the first exposure to the substance, seemed to become overly sensitive to any further exposure. Ordinarily, the introduction of a foreign substance into the bloodstream causes the immune system to create antibodies to neutralize the threat and protect against any subsequent invasion by the same intruder. In Richet's observations, however, the antibodies did not provide protection, but instead caused a state of hypersensitivity to the substance, so that the smallest subsequent exposure brought on a state of shock that was often fatal. Richet termed this condition anaphylaxis, using the opposite of the Greek word for protection. Anaphylactic shock produces symptoms that can include skin rashes, labored breathing, vomiting, and lowered blood pressure. Today, doctors can treat the condition with epinephrine and other drugs. Subsequently, Richet and others made further observations of anaphylaxis and the conditions under which it occurs. His research on immune-system response was very useful to later scientists, who developed many vaccines (see Immunization). Modern research and clinical practice in the diagnosis and treatment of allergic disorders also owe much to Richet's work.