The paradoxical relationship between animal dander, exposure, sensitization and asthma: is there a hierarchy of inhalant allergens?


Thomas A. E. Platts-Mills, University of Virginia, P.O. Box 801355, Charlottesville, VA, 22908, USA.


Although sensitization to allergens is undoubtedly dependent on exposure, there is now extensive evidence that high exposure to cat allergens does not consistently increase the prevalence of sensitization. Investigating this paradoxical effect of high exposure provides an opportunity to understand the mechanisms of control of allergic disease. The evidence suggests that the T cell response to specific peptides in Fel d 1 is important to the development of tolerance. In addition, it is possible that the “tolerant” response to cat allergens is sufficient to explain why the prevalence and severity of allergic disease (particularly asthma) is lower in those countries where (because of the absence of dust mites) cats are the dominant source of indoor allergens.