RISE IN TOTAL IGE AS AN INDICATOR OF ALLERGIC BRONCHOPULMONARY ASPERGILLOSIS IN CYSTIC-FIBROSIS

Background - Allergic bronchopulmonary aspergillosis is a serious comp lication of cystic fibrosis and may be difficult to diagnose. The aim of this study was to define the usefulness of measuring total IgE comp ared with other major criteria in the diagnosis of allergic bronchopul monary aspergillosis in children with cystic fibrosis. Methods - A ret rospective analysis was carried out of the case records of 160 childre n attending a tertiary referral paediatric cystic fibrosis clinic. Res ults - Sixteen children had a total IgE level above 500 IU/ml. Eleven children had six or more other major criteria and were considered to h ave allergic bronchopulmonary aspergillosis. These 11 children had a f ourfold rise in IgE in association with clinical deterioration. A furt her child had a fourfold rise in IgE to 341 IU/l, and was also thought to have allergic bronchopulmonary aspergillosis. Eleven had a fall in IgE with successful treatment; one patient died with uncontrolled dis ease. Only one of these 12 children had negative precipitins to Asperg illus fumigatus. The five children with a raised IgE not thought to ha ve bronchopulmonary aspergillosis had four or fewer major criteria and were not treated; none had positive precipitins. Conclusions - A four fold rise in total IgE, particularly to above 500 IU/ml, is strongly s uggestive of the diagnosis of allergic bronchopulmonary aspergillosis in children with cystic fibrosis. The measurement of total IgE has the merit of being simple to perform and objective. Positive aspergillus precipitins provide useful confirmatory evidence. These two criteria, taken in conjunction with clinical deterioration and new radiological shadowing, allow simplification of the diagnosis of allergic bronchopu lmonary aspergillosis in cystic fibrosis.