HIGH IGE LEVELS IN ABPA: A RISK FACTOR FOR SEVERE ASTHMA EXACERBATION AMONG YOUNG POPULATION

Abstract

OBJECTIVE: To determine whether young adults with acute Allergic Bronchopulmonary Aspergillosis (ABPA) and very high serum total IgE levels and Aspergillus fumigatus-specific IgE exhibit a distinct clinical phenotype with preserved lung functions, yet are at significant risk of recurrent severe asthma exacerbations.

MATERIALS AND METHODS: This multicenter prospective cohort study was conducted across tertiary care hospitals in Pakistan, from June 2024 to July 2025. Seventy-two patients aged 18–35 years with acute ABPA (diagnosed per ISHAM criteria) and no bronchiectasis on HRCT were enrolled. Total IgE and Aspergillus fumigatus-specific IgE (AF-IgE) were measured using ImmunoCAP at a central laboratory. All participants received standardized oral prednisolone (0.5 mg/kg/day for 2 weeks, tapered over 6–8 weeks). Clinical assessments, spirometry (FEV₁), ACQ-5 scores, and serial IgE levels were recorded at baseline, Week 8, Week 12, and Week 24. Exacerbation frequency was documented prospectively. Data were analyzed using SPSS v28.0; paired t-tests, logistic regression, and Pearson correlation were applied; p < 0.05 was considered statistically significant.

RESULTS: Despite mean baseline ACQ-5 scores of 1.6 ± 0.4 (indicating mild control), 89% (n=64) experienced ≥2 severe exacerbations in the prior year. Mean total IgE was 3200 ± 1580 IU/mL; Mean total AF-IgE was 35 ± 22.1 kUA/L. Post-steroid, total IgE declined by 38% at 8 weeks (p<0.001) and 82% at 12 weeks. FEV₁ improved from 82% to 94% predicted (p=0.002). Notably, patients with IgE > 3000 IU/mL had 3.2 times higher exacerbation risk (OR 3.2, 95% CI 1.8–5.7, p=0.001) despite similar symptom scores.

CONCLUSION: High IgE levels in young ABPA patients can be misleading, as they often have relatively normal lung function and mild symptoms. However, these patients are at risk of severe asthma attacks, frequent exacerbations lead to hospitalization, that is not respondent with standard treatments like inhaled corticosteroids. IgE decline with oral corticosteroids correlates with clinical improvement, supporting IgE as both a biomarker and therapeutic indicator.