Cat allergen exposure increases asthmatic responses in non cat-allergic people

A new study has found that exposure to cat allergen might increase bronchial responsiveness (BR) in people with certain common allergies, even if they are not specifically allergic to cats.

Washington, July 2 : A new study has found that exposure to cat allergen might increase bronchial responsiveness (BR) in people with certain common allergies, even if they are not specifically allergic to cats.

The study was conducted by a team of researchers led by Susan Chinn at the Imperial College in London.

As part of the study, researchers examined cross-sectional data from 1,884 participants in 20 centres in the European Community Respiratory Health Survey (ECRHS) follow-up, which involved measurements of house dust mite and cat allergen in mattress dust samples, and data on IgE sensitisation to four major allergens-cat, house dust mite, Cladosporidium (a common mould) and timothy grass.

Researchers found that the difference in BR between those who had low versus high exposure to cat allergen was almost as great a difference as that between non-asthmatic and asthmatic individuals in the United Kingdom centres of the ECRHS.

"We presupposed that we would find increased responsiveness only in those individuals who were exposed to cat allergen and whose blood tests showed that they were allergic to cats. But our study suggests that all allergic individuals have signs of asthmatic responses if exposed to cat allergen, even if blood tests show that they are not allergic to cats," Dr. Chinn said.

The study noted that more than one in four of the individuals included in the ECRHS were sensitised to at least one of the allergens tested, indicating that avoidance of cat exposure would be beneficial to a much wider population than previously expected.

Furthermore, cat allergen levels were ubiquitous in cat-owning communities, and their results showed effects of cat allergen exposure at lower levels than generally regarded necessary to produce a measurable result.

The study supported and clarified previous research that found that asthma is strongly related to indoor allergens and that patients with specific sensitisation exhibit greater BR in response to exposure to the allergens to which they are sensitised.

"Based on the current research, it appears that many individuals could benefit from reduced cat ownership and exposure. However, because the findings were unexpected, it is important that results are replicated in other studies before firm recommendations are made," Dr. Chinn added.

The findings of the study were published in the July issue of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.

ANI