ELEMENTAL CONTENT OF AIRWAY SURFACE LIQUID FROM INFANTS WITH CYSTIC-FIBROSIS

We tested the hypothesis that airway surface liquid (ASL) electrolyte composition is altered in infants with cystic fibrosis (CF) and that t he presence of airway inflammation affects ASL composition. We measure d the tracheal ASL sodium and chloride concentration and examined bron choalveolar lavage (BAL) fluid cytology, interleukin-8 (IL-8) concentr ations, and quantitative bacterial culture in 19 infants and young chi ldren with CF. Seven infants undergoing bronchoscopy for the evaluatio n of strider served as non-CF controls. In addition, we measured nasal ASL sodium and chloride concentrations from 10 young adults with CF a nd from 10 control subjects. On the basis of the BAL findings, the inf ants with CF were divided into three groups: one with little evidence of pulmonary inflammation (CF-NI, n = 5); one with obvious pulmonary i nflammation (CF-I, n = 7); and an intermediate group (CF-MI, n = 7). W e found the ASL sodium was not different among any of the four groups (means mM +/- SE, 85 +/- 10 controls; 78 +/- 16 CF-NI; 83 +/- 9 CF-MI, 84 +/- 9 CF-I). In contrast the ASL chloride was lower in the CF-NI g roup when compared with control subjects (108 +/- 5 control subjects; 77 +/- 7 CF-NI, p < 0.01). In the CF-I and CF-MI groups, the ASL chlor ide concentrations were of intermediate values (CF-I 95 +/- 10 mM; CF- MI 96 +/- 9 mM) and not significantly different from controls. Results from the nasal ASL analysis showed no significant differences in sodi um and chloride concentrations in the CF group compared with control s ubjects. These results suggest that the primary abnormality of ASL com position is a reduction in chloride concentration. ASL composition app ears to be affected by the presence of airway inflammation.