Phenotype of MPs present in sputa of acute and stable CF and PCD patients. In acute and stable CF patients, the number of MPs staining positive for FITC-conjugated antibodies directed against CD11a are significantly higher than in PCD patients (A). Stable CF vs. PCD: *p = 0.0464. Acute CF vs. PCD: *p = 0.0431. MPs positive to CD66b, both in acute and in stable phase of CF, are significantly elevated in respect to PCD (B). Stable CF vs. PCD: *p = 0.0373. Acute CF vs. PCD: **p = 0.0046. Positivity of MPs to CD11b is not significantly different in the three groups of patients (C).