SURFACTANT COMPOSITION IN INFANTS AND YOUNG-CHILDREN WITH CYSTIC-FIBROSIS

We tested the hypothesis that the composition of bronchial surfactant is normal in infants with cystic fibrosis (CF) in the absence of activ e lung disease but that it is altered by lower respiratory tract infec tion and inflammation. We examined the total phospholipid (PL), disatu rated phospholipid (DSP), surfactant protein-a (SP-A), surfactant prot ein B (SP-B), and surface activity in bronchoalveolar lavage fluid fro m 27 subjects with CF whose mean age was 22.7 (SD 14.5) mo. Six infant s with strider served as non-CF controls. Twelve of the subjects with CF (CF-I group) had evidence of active pulmonary infection or inflamma tion which was absent in the remaining 15 subjects (CF-NI group). We f ound no differences in the surfactant composition or activity between controls and the CF-NI group. In contrast, the DSP/PL ratio was lower in the CF-I subjects than in both the CF-NI subjects (p = 0.05) and co ntrols (p < 0.01) suggesting a disturbance of surfactant function. SP- A concentrations were higher in the CF-I group compared to the other t wo groups (p < 0.05). These results suggest that the bronchial surfact ant of infants with CF is altered following lower airway infection and inflammation and is not a primary abnormality associated with this di sorder.