New Treatment May Scratch Out Cat Allergies

Experimental Approach May Eventually Treat Cat and Food Allergies

From the WebMD Archives

March 28, 2005 - A new therapy may one day allow humans to lick their cat allergies and perhaps even take a bite out of food allergies, a new study suggests.

Researchers tested a novel protein in mice bred to be allergic to cats and in human cells made to react to cat allergens. They found the therapy successfully prevented allergic reactions after exposure to cat dander.

The injectable treatment consists of a feline allergen protein and a human antibody that are bound together to block the release of histamine, which causes allergic symptoms like sneezing and itchy, watery eyes.

"This novel approach to treating cat allergies is encouraging news for millions of cat-allergic Americans. Moreover, these results provide proof-of-concept for using this approach to develop therapies to prevent deadly food allergy reactions as well," says Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, which funded the study, in a news release.

The results of the study appear in the current issue of Nature Medicine.

New Way to Treat Cat Allergies

In the study, researchers evaluated the effects of the specially engineered protein in blood samples of people with cat allergies and in mice bred to be allergic to cats.

At one end of the novel protein, called gamma Feline domesticus (GFD), is a protein found in cat dander and saliva that triggers the release of histamine in people allergic to cats. At the other end is a human antibody, which blocks the allergic reaction that releases histamine.

In the first test, researchers looked at how the human cells treated with GFD reacted after exposure to a cat protein.

"We measured more than 90 percent less histamine in the cultures with GFD," says researcher Andrew Saxon, MD, of UCLA, in a news release. "Those results suggested that GFD successfully prevented the immune cells from reacting to cat allergen. The next step was to test GFD in mice that we had made allergic to the allergenic protein found in cat saliva and dander."

The mice tests showed that the experimental therapy blocked the allergic reaction involving histamine, and the allergic mice had similar responses to cat dander as non-allergic mice.

Researchers say these results show that this therapy has the potential to prevent allergic reactions long after the injections stop, but further study is needed before it can be used in people with cat allergies.

Show Sources

SOURCES: Zhu, D. Nature Medicine, March 27, 2005, advance online publication. News release, National Institute of Allergy and Infectious Diseases.
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