Good news for allergic cat-owners

Abstract

A recent study in the Lancet shows that high levels of cat allergen in the home decrease the risk of asthma by altering the antibody response. It is known that exposure to high levels of house dust mites increases the production of IgE antibodies, but the same does not appear to be true of exposure to cat allergen. Thomas Platts-Mills and colleagues at the University of Virginia's Asthma and Allergic Diseases Center measured levels of cat allergen in the homes of 226 children, aged 12–14, 47 of whom had symptoms of asthma and bronchial hyper-reactivity. The levels of antibodies to dust mite and cat allergens, measured by isotype-specific (IgG and IgG4) radioimmunoprecipitation assays, were compared with sensitization to the allergen concentrations found in house dust. The researchers found an increased prevalence of sensitization and specific IgG antibody associated with increased exposure to dust mites. By contrast, they found that exposure to higher levels of cat allergen is associated with decreased sensitization but a higher prevalence of specific IgG. The authors conclude that, ‘…exposure to cat allergen can produce an IgG and IgG4 antibody response without sensitization or risk of asthma.’ Lancet (2001) 357, 752–756 HM