Researchers look at cats – not humans – for future allergy remedies

Anyone who has watched an allergic friend react to a beloved pet knows the dark powers that lurk in that luxurious feline fur. Within minutes, an allergic human exposed to a cat can begin sneezing and wheezing, their eyes watering and itching.

Solutions for people with allergies who want to be around cats tend to be costly, labor-intensive, of questionable value and sometimes defy common sense.

One recommendation is to bathe the cat weekly. How many urgent care trips would ensue if most of us tried to give our cats baths frequently?

Other recommendations are to get rid of rugs, vacuum-clean frequently and get a HEPA air purifier. There also are allergy shots and medications.

But in a country that has more than 50 million cats in more than 20 million homes, some researchers are searching for better solutions. Instead of trying to change humans or their environment, they're trying to change cats.

Purina has introduced a cat food — Pro Plan LiveClear — that it says can reduce the protein that most allergic people react to by 47% after three weeks.

"This is really, in my mind as a veterinarian, a groundbreaking and revolutionary pet food," said Dr. Kurt Venator, Purina's chief veterinary officer. "We truly believe this is going to help cats and people get closer together."

Cat allergies affect 10% to 20% of adults. More than 90% of them react to Fel d 1. And researchers say allergies to furry animals are increasing.

Fel d 1 is produced in salivary, skin and anal glands of cats and is found in their tears. Cats spread it when they clean themselves and when they shed fur or dander. All cats make the protein, including hairless cats, although amounts vary by cat or even by day.

Dr. Bruce Kornreich, director of the Cornell Feline Health Center, said there is evidence that uncastrated male cats make more of it than females or neutered males. There is no such thing as a hypoallergenic cat.

There also is no way to totally escape Fel d 1. It rides on people's clothes to work and school.

"It's everywhere," said Dr. James Wedner, an allergist at Washington University in St. Louis.

Nicole Brackett, a postdoctoral researcher with Indoor Biotechnologies, sequenced the genes that make Fel d 1 in 50 domestic cats as well as some big and wild cats. She said the genes are not "well conserved" in the domestic cats, a sign that they likely are not essential.

Purina's approach to fighting allergies started about a decade ago when Ebenezer Satyaraj, a nutritional immunologist, learned his daughter was allergic to cats. He discovered that chickens produce an antibody to Fel d 1 that can be found in their eggs.

The company added the antibody to cat food. The resulting food neutralized up to about half of the Fel d 1 that some cats produced.

That means cats eating the food are still making Fel d 1, of course, so it does not automatically mean allergic people will feel better around them. However, Wedner said higher doses of an allergen generally cause more symptoms.

But Dr. Patrick Gleeson, an allergist at Penn Medicine, said that while Purina's new food is promising, doctors "don't really know how much allergen reduction is necessary in order to reduce symptoms."

Kornreich said one concern with this type of vaccine is an errant immune reaction.

"There's always a concern that the immune system can be stimulated to start neutralizing things that are not the target of interest," he said.

Dr. Elizabeth Knighton, a veterinarian with City Cat Vets in Philadelphia, said she'd be more comfortable with the special food, which neutralizes Fel d 1 after the cat makes it, than with making bigger biological changes to cats.