The serum was written about in an editorial in the Journal of the American Mecial Association in October of 1904. The authors noted that there were a lot of theories as to the cause of hay fever: the heat theory, the light theory, the nervous theory, the pollen theory and the bacteria theory were just a few. Yet all that was known for sure about the disease was (1):
- You had to have a have a predisposition to suffer from it
- There had to be an exciting cause to trigger it.
He learned that when a pollen was inserted into the eyes of hay fever sufferers it caused inflammation and redness of the mucous layers around the eyes. He later discovered that it was not the pollen itself that caused this reaction, but a protein (toxalbumin) produced by pollen. When exposed to that protein, the symptoms of hay fever were present. (1)
His studies were interesting in that he discovered that "as little as 1/40,000 of a milligram of the rye-pollen toxin placed in the conjunctival sac (around the eyes) will call forth in certain individuals a paroxysm of hay fever lasting several hours." (1)
The serum only caused hay fever symptoms in those people with a susceptibility (or predisposition), and had no effect on any one else. His research basically confirmed the theories of Blackley, that pollen was a cause of hay fever. He, thus, proved the pollen theory of hay fever. (1)
Yet Dunbar didn't stop there. By further experiments:
The technique he used was called passive immunization. He "injected young thoroughgbred horses with pollen toxin in increasingly large doses, (and) produced what he believed to be an antitoxin in the horse's blood that neutralized the pollen's effects," writes historian Gregg Mittman in 2007. (2, page 56)"Dunbar found on mixing the toxalbumin with the serum of animals which had been previously treated with pollen or the extracted poison that the former was rendered innocuous. Unlike diphtheria antitoxin, the hay-fever serum is not to be used subcutaneously, for subcutaneous injections give rise to unpleasant symptoms—itching, swelling and erythema. Experiments have shown that the local application of the serum to the irritated mucous membrane is more effective than its introduction hypodermically.
In one study 222 hay fever sufferers were treated with the serum, and 127 found it to be effective. The medicine was believed to be most effective if given every morning during the hay fever season, and it lasted for several hours to an entire day, even when the patient spends the day "in the open air." (1)
Dunbar patented his serum in Germany, England and the United States as Pollantin. To treat hay fever patients the serum, a liquid or powder, must be administered frequently, such as every morning, to the mucus layers of the nasal passages and around the eyes.
It was soon realized that Pollantin wasn't what it was cracked up to be. Not only did it not really work, it caused aniphylactic shock in some patients exposed to it. (2, page 56) So the quest was on to find a better remedy. This research would ultimately lead to the discovery of desensitization and antihistamines.
- "The situation in regards the serum treatment of hay fever," The Journal of the American Medical Association, Editorial, Saturday, October 15, 1904, page
- Mittman, Gregg, "Breathing Space," 2007, New Haven and London, Yale University Press