[Aspergillus fumigatus and Candida albicans in cystic fibrosis: clinical significance and specific immune response involving serum immunoglobulins G, A, and M].

OBJECTIVE: The aim of this study was to analyze the clinical significance of Aspergillus fumigatus and Candida albicans in respiratory secretions from patients with cystic fibrosis and to assess the immune response to these fungi in serum. PATIENTS AND METHODS: The study included 66 patients with cystic fibrosis (34 men; mean age, 16.2 years). Sera from 15 healthy individuals were used as controls.
RESULTS: The serum concentrations of immunoglobulin (Ig) G, IgA, and IgM against A fumigatus and C albicans were higher in patients than in the control group. There was no correlation between the presence of A fumigatus in respiratory secretions and the immune response to the fungus measured in serum. In contrast, the presence of C albicans in respiratory secretions was correlated with the immune response to that fungus. The likelihood of obtaining A fumigatus cultures from respiratory secretions increased with age. The presence of these fungi in respiratory samples was not a risk factor for greater respiratory impairment.
CONCLUSIONS: In response to increased colonization of the lower respiratory tract by A fumigatus and C albicans, patients with cystic fibrosis have elevated serum levels of IgG, IgA, and IgM against those fungi. In patients with cystic fibrosis, culture of sputum and oropharyngeal secretions is adequate for the assessment of lower respiratory tract colonization by C albicans but not A fumigatus. Fungal colonization of the lower respiratory tract is not a risk factor for greater respiratory impairment in patients with cystic fibrosis.