- The term anaphylaxis is from the Greek ana, which means “away from” and phylaxis meaning “protection.”
- The term was coined by by Portier and Richet who were studying the effects of a toxin from a Mediterranean Sea anemone on dogs.
- They gave an initial dose of the toxin to the dogs, then weeks later a second dose was given to see if the dogs had developed immunity to the toxin.
- Some of the dogs did not show increased resistance but died within minutes of the second dose.
- They exhibited breathing difficulties, paralysis, excessive salivation and defecation.
- These dogs suffered from massive histamine release – anaphylactic shock.
- What happened was that after the first exposure to the sea anemone toxin, the dogs made IgE antibodies that attached to a special type of white blood cell called basophils.
- The IgE antibodies also attached to mast cells, another type of cell containing histamine, heparin and other substances in granules.
- When the toxin was detected by the immune system a second time, it immediately bound to the IgE and this antigen/antibody complex caused the basophils and mast cells to break open and release the histamine, heparin and other substances into the body.
- Histamine causes vasodilation, bronchospasm, contraction of the GI tract, capillaries to become leaky, rhinorrhea, watery eyes, urticaria, itching and subsequent vascular collapse.
- These dogs did not stand a chance. [10]
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