Prevalence of sensitization to Aspergillus flavus in patients with allergic bronchopulmonary aspergillosis

Abstract

Aspergillus fumigatus is the most common Aspergillus species worldwide; however, A. flavus has also been shown to be prevalent in North India. Herein, we investigate the prevalence of sensitization to A. flavus in subjects with allergic bronchopulmonary aspergillosis (ABPA). We also evaluate the occurrence of allergic bronchopulmonary mycosis (ABPM) due to A. flavus. Treatment-naive subjects with ABPA underwent sputum culture; and, skin testing, fungal-specific immunoglobulin E (IgE) and serum precipitation tests for A. fumigatus and A. flavus. Sensitization to A. flavus was diagnosed if any immunological test for A. flavus was positive in subjects with ABPA. ABPM was labelled as probable if sputum cultures grew A. flavus and A. flavus-specific IgE was greater than A. fumigatus-specific IgE; and, possible if only A. flavus-specific IgE was greater than A. fumigatus-specific IgE. Fifty-three subjects with a mean (SD) age of 34.2 (12.8) years were included. Sensitization to A. flavus was seen in 51 (96.2%) subjects, with overlap occurring in 49 (92.5%), 21 (39.6%), and 12 (22.6%) instances on fungal-specific IgE, skin prick test and precipitins, respectively. Sputum culture was positive in 18 (33.9%; A. flavus [n = 12], A. fumigatus [n = 6]) subjects. ABPM due to A. flavus was diagnosed in 16 (30.2%) subjects (10 probable, 6 possible). They were more likely to have high-attenuation mucus and a trend towards higher occurrence of sinusitis, compared to ABPA. We found a high occurrence of sensitization to A. flavus in subjects with ABPA. Subjects with A. flavus-related ABPM had a higher likelihood of high-attenuation mucus and probability of sinusitis. More studies are required to confirm this observation.

Keywords: Aspergillus; ABPA; ABPM; asthma; cystic fibrosis; fungal sensitization.