Childhood asthma: clinical and immunological changes over a decade.

A group of 26 Australian asthmatic children with laboratory-proven bronchial hyper-reactivity to the allergens of rye grass pollen and/or the house dust mite has been studied over a 9-year period. Clinical symptoms and drug scores were used to evaluate the severity of the patients' asthma and, wherever possible, blood samples were obtained before, during and after the rye grass pollen seasons. The cumulative symptom and drug scores for the 20 patients with bronchial hyper-reactivity to rye grass pollen extract tended to increase during and fall after each pollen season but the peaks were of decreasing amplitude over the 9 years. Since a proportion of these patients underwent hyposensitization to rye grass during year 1, longitudinal comparisons were made between year 2 and year 9. Comparing the individuals at the same three seasonal time-points revealed significantly lower drug scores in year 9 compared with year 2, and in parallel with this, significantly lower total IgE, IgE anti-rye and IgG anti-rye antibodies at all three assessment points. In the 14 patients with bronchial hyper-reactivity to house dust mite the severity of the asthma and the median levels of IgE and IgG mite specific antibodies all decreased over the study period. Despite the progressive improvement in asthma and diminishing immune responses to both rye grass and house mite in the patients, no immunological feature could be identified that correlated significantly with clinical outcome.