Common inflammatory markers predict risk of ABPA development in children with cystic fibrosis

Allergic bronchopulmonary aspergillosis (ABPA) contributes to progressive lung damage in people with cystic fibrosis (pwCF), particularly when diagnosis is delayed. Early diagnosis remains challenging due to insidious onset and non-specific symptoms. We aimed to assess the utility of routinely collected biomarkers in predicting ABPA in children with CF.

A retrospective analysis of pwCF aged 0-18 years in Western Australia from 2000 to 2020. Longitudinal levels of total IgE, eosinophils (Eo), and Aspergillus-specific IgE (Asp-sp IgE) preceding ABPA diagnosis were compared with age- and sex-matched controls.

Among 346 children with CF, 19 (5.4%) were diagnosed with ABPA. Distinct elevations in Asp-sp IgE, total IgE, and Eo were observed up to five years before clinical diagnosis. Total IgE almost doubled and Asp-sp IgE nearly tripled in the three years preceding diagnosis. Persistent normal values across all three markers were strongly associated with low risk of ABPA. Children with total IgE levels <500 IU/mL, Asp-sp IgE <0.35 IU/mL, and Eo <0.5 × 10⁹ cells/L, had a negligible risk (<1.0%) of ABPA over the next five years and very low risk (4.5%) over twelve years.

Biomarker elevations in children who develop ABPA are not sudden but emerge early and persist over time. Conversely, children with low levels in at least two of total IgE, Eo, and Asp-sp IgE are at negligible risk of ABPA for at least five years and therefore may only require screening every five years. In contrast, children with elevated levels should be monitored more closely.