Clinical characteristics of allergic bronchopulmonary mycosis caused by Schizophyllum commune

Abstract

Background: Allergic bronchopulmonary mycosis (ABPM) is an allergic disease caused by type I and type III hypersensitivity to environmental fungi. Schizophyllum commune, a basidiomycete fungus, is one of the most common fungi that causes non-Aspergillus ABPM.

Objective: Herein, we attempted to clarify the clinical characteristics of ABPM caused by S. commune (ABPM-Sc) compared with those of allergic bronchopulmonary aspergillosis (ABPA).

Methods: Patients with ABPM-Sc or ABPA were recruited from a nationwide survey in Japan, a multicenter cohort, and a fungal database at the Medical Mycology Research Center of Chiba University. The definition of culture-positive ABPM-Sc/ABPA is as follows: (1) fulfills five or more of the 10 diagnostic criteria for ABPM proposed by Asano et al., and (2) positive culture of S. commune/Aspergillus spp. in sputum, bronchial lavage fluid, or mucus plugs in the bronchi.

Results: Thirty patients with ABPM-Sc and 46 with ABPA were recruited. Patients with ABPM-Sc exhibited less severe asthma and presented with better pulmonary function than those with ABPA (p = 0.008-0.03). Central bronchiectasis was more common in ABPM-Sc than that in ABPA, whereas peripheral lung lesions, including infiltrates/ground-glass opacities or fibrotic/cystic changes, were less frequent in ABPM-Sc. Aspergillus fumigatus-specific immunoglobulin (Ig)E was negative in 10 patients (34%) with ABPM-Sc, who demonstrated a lower prevalence of asthma and levels of total serum IgE than those with ABPM-Sc positive for A. fumigatus-specific IgE or ABPA.

Conclusions: Clinical characteristics of ABPM-Sc, especially those negative for A. fumigatus-specific IgE, differed from those of ABPA.

Keywords: Aspergillus; Schizophyllum commune; allergic bronchopulmonary aspergillosis; allergic bronchopulmonary mycosis; asthma.

FIGURE 1

Peripheral eosinophil counts (A) and total serum IgE levels (B) among the cases of ABPM‐Sc negative or positive for A. fumigatus‐specific IgE (n = 10 and 19, respectively) and ABPA (n = 46). The number of cases with less than 1000 IU/mL in total IgE concentration was 8 (80%), 3 (16%), and 17 (37%) in ABPM‐Sc negative or positive for A. fumigatus‐specific IgE and ABPA, respectively. ABPM‐Sc, ABPM culture positive for S. commune; ABPA, allergic bronchopulmonary aspergillosis; Ig, immunoglobulin.