Growing out of asthma: Clinical and immunological changes over 5 years

Asthmatic children with bronchial reactivity to a seasonal allergen, rye-grass pollen, and/or a perennial allergen, Dermatophagoides pteronyssinus, were studied over 5 years. Changes in their clinical symptoms and drug usage were correlated with changes in levels of serum IgG and IgE antibodies to the rye and mite allergens. The overall clinical severity of the children's asthma declined significantly during the study period and was accompanied by a significant fall in IgG and IgE anti-mite antibodies. The asthma of those children with bronchial reactivity to rye-grass pollen continued to be exacerbated in the pollen season of year 5, and both IgG and IgE anti-rye antibodies continued to rise and fall in relation to the season. These observations suggest that long-term perennial allergen exposure favours the induction of clinical and immunological hyporesponsiveness, whereas intermittent seasonal allergen exposure is associated with persistent clinical and immunological hypersensitivity.