INCREASED DNA LEVELS IN BRONCHOALVEOLAR LAVAGE FLUID OBTAINED FROM INFANTS WITH CYSTIC-FIBROSIS

Airway inflammation in children younger than 5 yr of age is difficult to assess, particularly in patients with cystic fibrosis (CF). Further more, determining responses to therapies is often subjective in infant s, especially those with CF. To determine whether airway DNA levels co uld be used as an index of airway inflammation, we measured DNA levels in bronchoalveolar lavage fluid (BALF), using a Hoechst dye-binding a ssay. BALF DNA levels and neutrophils from 16 infants with CF were com pared with levels obtained from seven older CF patients and nine contr ol children who underwent bronchoalveolar lavage for evaluation of oth er pulmonary diseases. BALF DNA was increased in both infants (3.2 +/- 0.7 mu g/ml) and older patients with CF (5.4 +/- 0.9 mu g/ml) compare d with the controls (0.7 +/- 0.2 mu g/ml) (mean +/- SEM). BALF DNA lev els were not significantly different between infants and older patient s with CF. BALF neutrophil counts in CF patients were significantly hi gher than in controls, Furthermore, BALF DNA levels and total neutroph il counts in infants with CF correlated positively with one another. W e conclude that: (1) DNA levels were easily quantifiable in BALF of yo ung children; (2) DNA levels in BALF from CF patients were greater tha n in a group of children with other pulmonary diseases, and that in so me infants with CF, BALF DNA levels were equivalent to those of much o rder patients with CF; (3) DNA levels in BALF correlate with BALF neut rophil number, an index of inflammation; and (4) some infants with CF have increased levels of DNA in BALF, which may justify a clinical tri al of aerosolized rhDNase in this population.