High attenuation mucus in bronchi with allergic bronchopulmonary mycosis.

BACKGROUND: High-attenuation mucus (HAM) is a specific manifestation of allergic bronchopulmonary mycosis (ABPM) on chest computed tomography (CT). OBJECTIVES: To compare the diagnostic accuracy of the two definitions of HAM and to clarify the clinical and radiographic characteristics of HAM-positive and HAM-negative ABPM. METHODS: CT images at the diagnosis of ABPM using Asano's criteria were retrospectively analysed. In Study #1, radiographic data obtained using the same CT apparatus in a single institute were analysed to determine the agreement between the two definitions of HAM: a mucus plug that is visually denser than the paraspinal muscles or that with a radiodensity ≥70 Hounsfield units. In Study #2, HAM was diagnosed by comparison with the paraspinal muscles in patients with ABPM reporting to 14 medical institutes in Japan. RESULTS: In Study #1, 93 mucus plugs from 26 patients were analysed. A substantial agreement for HAM diagnosis was observed between the two methods, with a κ coefficient of 0.72. In Study #2, 60 cases of ABPM were analysed; mucus plugs were present in all cases and HAM was diagnosed in 45 (75%) cases. The median A. fumigatus-specific IgE titre was significantly lower in HAM-positive patients than in HAM-negative patients (2.5 vs. 24.3 UA /mL, p = .004). Nodular shadows were observed more frequently in the airways distal to HAM than in those distal to non-HAM mucus plugs (59% vs. 32%, p < .001). CONCLUSION: In conclusion, agreement between the two methods to diagnose HAM was substantial. HAM was associated with some immunological and radiographic characteristics, including lower levels of sensitization to A. fumigatus and the presence of distal airway lesions.

Clinical characteristics of allergic bronchopulmonary mycosis caused by Schizophyllum commune.

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.

Activation of ILC2s through constitutive IFNγ signaling reduction leads to spontaneous pulmonary fibrosis.

Pulmonary fibrosis (PF), a condition characterized by inflammation and collagen deposition in the alveolar interstitium, causes dyspnea and fatal outcomes. Although the bleomycin-induced PF mouse model has improved our understanding of exogenous factor-induced fibrosis, the mechanism governing endogenous factor-induced fibrosis remains unknown. Here, we find that Ifngr1-/-Rag2-/- mice, which lack the critical suppression factor for group 2 innate lymphoid cells (ILC2), develop PF spontaneously. The onset phase of fibrosis includes ILC2 subpopulations with a high Il1rl1 (IL-33 receptor) expression, and fibrosis does not develop in ILC-deficient or IL-33-deficient mice. Although ILC2s are normally localized near bronchioles and blood vessels, ILC2s are increased in fibrotic areas along with IL-33 positive fibroblasts during fibrosis. Co-culture analysis shows that activated-ILC2s directly induce collagen production from fibroblasts. Furthermore, increased IL1RL1 and decreased IFNGR1 expressions are confirmed in ILC2s from individuals with idiopathic PF, highlighting the applicability of Ifngr1-/-Rag2-/- mice as a mouse model for fibrosis research.