The influence of schizophyllum commune on asthma severity

Background: The sensitization and exposure to fungal allergens have been reported to be associated with asthma. The aim of this study was to clarify the impact of sensitization to Schizophyllum commune (S. commune) on the severity and exacerbations of asthma. Methods: Ninety-two patients with asthma of various levels of severity [mild (n = 18), moderate (28), and severe (46)] and exacerbation severity [moderate (n = 43) and severe (6)] were retrospectively examined with regard to fungal sensitization such as specific IgE or intradermal skin reactions against S. commune and other common allergens. We also classified the patients into three groups: (1) three or more asthma attacks during the past year (F-BA) (n = 29),(2) one or two asthma attacks (NF-BA) (n = 20), and (3) no asthma attack (C-BA) (n = 43). Results: The positive rate of late cutaneous reactions to S. commune was higher in patients with severe asthma (41.2%) than with moderate (26.1%) or mild asthma (6.7%), and was significantly different among the three groups (P < 0.05). Although the ratio did not show a significant difference between the patients with severe (83.3%) or moderate (36.1%) exacerbation, it was higher in F-BA (60.9%) than in NF-BA (21.1%) and C-BA patients (10.0%), and it was significantly different among the three groups (P = 0.0002). Multivariate analysis identified positive results for late-phase skin reactions to S. commune and the age of the patients as an independent determinant of asthma severity, and the skin results and %FVC an independent determinant of exacerbation frequency. Conclusion: This study demonstrated that S. commune is an environmental fungus that appears to enhance both the severity of asthma and the exacerbation frequency.