2.1 Human volunteers
Healthy donors were recruited among staff members of the Fondazione Mario Negri Sud. All signed an informed consent form. Individuals with CF (demographic characteristics are reported in Table 1) were recruited at the Cystic Fibrosis Center of the Atri Hospital (TE, Italy) on an outpatient basis. Patients and their parents were informed about the rationale and objectives of the study and asked to sign the relative form. The experimental protocol was communicated to the Ethic Committee of the Institution, according to the national guidelines (G.U. n. 76 del 31-03-2008). Inclusion criteria: no antibiotics or steroids for at the least two weeks before blood collection. Blood (15 ml) was collected in the occasion of a scheduled routine control. Pulmonary function was evaluated after a suspension of at least 12 hours of bronchodilator or leukotriene receptor antagonist administration.