Roles of Mycological and Pathological Examinations of Bronchoscopic Specimens in the Diagnosis of Allergic Bronchopulmonary Aspergillosis/Mycosis.

BACKGROUND

Colonization by filamentous fungi in the bronchi is an essential pathogenic component of allergic bronchopulmonary aspergillosis/mycosis (ABPA/ABPM). Mycological or pathological examination of mucus plugs and bronchial lavage fluid directly recovered from the lower airways using bronchoscopy may improve the diagnosis of ABPA/ABPM.

OBJECTIVE

This study investigated the usefulness of mycological and pathological examinations of bronchoscopic specimens in the diagnosis of ABPA/ABPM.

METHODS

We retrospectively analyzed cases of ABPA/ABPM identified in a Japanese nationwide survey conducted in 2020. The diagnosis of ABPA/ABPM was made based on the criteria of Asano et al.

RESULTS

Bronchoscopy was performed in 307 of 423 patients with ABPA/ABPM (73%). Among the cases in which sputum and mucus plugs or bronchial lavage fluid were examined microbiologically (n = 216), the positive culture rate for fungi was significantly higher in the mucus plugs and bronchial lavage fluid than in the sputum (46% vs 35%; P = .001). Aspergillus spp, followed by Schizophyllum commune and Penicillium spp, were the most common fungi identified in mucus plugs and bronchial lavage fluid or in sputum. Pathological examination of mucus plugs was performed in 227 cases, and fungal hyphae were identified in approximately half of the cases (n = 113). After bronchoscopic examination, the diagnostic score of the criteria of Asano et al increased from 6.4 ± 1.2 to 7.0 ± 1.3 (P < .001), resulting in a higher rate of definite ABPA/ABPM diagnosis fulfilling six or more components of those criteria (77% vs 87%; P < .001).

CONCLUSION

Diagnostic bronchoscopy with detailed mycological and pathological evaluations can contribute to a more accurate diagnosis in some cases of ABPA/ABPM.