The goal of this study is to identify the immunological factors that influence a patient's response to the presence of the fungus Aspergillus fumigatus (A. fumigatus) in the lungs. In patients with cystic fibrosis (CF), this fungus is not known to cause damage to the lungs, but some patients respond with an allergic reaction that may cause wheeze, cough, or difficulty breathing. Approximately 230 patients will be enrolled with an additional 60 people who do not have CF and who do not have a history of asthma to serve as a comparison group.

In this cohort the investigators will study blood T-cell responses to Aspergillus antigens to determine if patients with ABPA have greater type 2 responses as measured by IL-13 compared to CF or non-CF controls.

Inclusion Criteria:

(CF)

• diagnosis of CF
• age 6 years or older
• presence of A. fumigatus in culture of airway flora, or the presence of one or more of the diagnostic criteria for ABPA (Control)
• age and sex matched to CF population

Exclusion Criteria:

(CF)

• uncontrolled CF-related diabetes mellitus
• use of oral steroids at a dose ≥ 0.5 mg/kg/day
• history of lung transplantation
• pulmonary exacerbation as defined by requirement for use of intravenous antibiotics or need for hospitalization within the preceding 14 days.
• patients who have a diagnosis of HIV and have a CD4+ Tcell count below 500 cells/ml will be excluded (control)
• asthma

Male and female subjects with CF who have A. fumigatus in cultures of airway flora and receive clinical care at the Antonio J. and Janet Palumbo Cystic Fibrosis Center at Children's Hospital of Pittsburgh. Age (± 1 year) and sex matched healthy, non CF controls will also be recruited.

This was an observational trial that involved no device or drug.