Cat lovers may reap an unexpected health benefit from their feline companions. Being around a cat appears to promote an immune response that protects children from cat allergies and asthma.
Asthma is increasingly prevalent, especially among children, but its causes are mysterious. Household allergens may be partly to blame, because allergies increase the risk for asthma. But the story isn't simple. Children exposed to household allergens from cockroaches and dust mites, for example, are more susceptible to allergies and asthma. But recent studies suggest that children living in a house with a cat are actually less likely to develop cat allergies and asthma.
To find out why, a team of researchers led by Thomas Platts-Mills of the University of Virginia, Charlottesville, measured antibody levels in 226 school children and compared those numbers to the amount of allergens in the children's homes. Children with the highest exposure to cat allergen had lower levels of the antibody IgE (the antibody that apparently triggers allergic reactions and asthma) than did children with an intermediate level of cat exposure, the team reports in the 10 March issue of The Lancet. They suspect the cat allergens stimulate a protective immune response.
The research suggests there are probably other allergens that protect some people against allergic responses, says Bengt Bjorksten of Linkoping University in Sweden. In fact, a similar response has been seen in bee keepers who seem immune to bee venom.