Dog allergy, a model for allergy genetics.

Experimental sensitization in dogs has revealed that the capacity to produce high levels of IgE against a variety of allergens (high IgE responders), an essential characteristic of the atopic state, is a genetic trait inherited in a dominant manner. In high IgE responder dogs spontaneous development of IgE to inhaled allergens, such as house dust mites, on the other hand, represents an apparent phenotype very similar to that observed in human atopic families. The full potential of the high IgE response gene appears to be fulfilled only under some conditions such as early and repeated exposition to allergens. It is therefore quite possible that the true phenotype of human atopy would also be inherited in a dominant fashion but not constantly expressed. This would explain why the increase in the prevalence of allergic diseases started long before the environmental factors currently accused could have been at play. This hypothesis, which can be verified experimentally, has important implications for the future of allergy.