LOWER AIRWAY INFLAMMATION IN INFANTS AND YOUNG-CHILDREN WITH CYSTIC-FIBROSIS

Airway inflammation is an important component of cystic fibrosis (CF) lung disease. To determine whether this begins early in the illness, b efore the onset of infection, we examined bronchoalveolar lavage (BAL) fluid from 46 newly diagnosed infants with CF under the age of 6 mo i dentified by a neonatal screening program. These infants were divided in-to three groups: 10 had not experienced respiratory symptoms or rec eived antibiotics and pathogens were absent in their BAL fluid; 18 had clear evidence of lower respiratory viral or bacterial (greater than or equal to 10(5) CFU/ml) infection; and the remaining 18 had either r espiratory symptoms, taken antibiotics, or had <10(5) CFU/ml of respir atory pathogens. Their BAL cytology, interleukin-8, and elastolytic ac tivity were compared with those from 13 control subjects. In a longitu dinal study to assess if inflammation develops or persists in the abse nce of infection, the results of 56 paired annual BAL specimens from 4 4 CF infants were grouped according to whether they showed absence, de velopment, clearance, or persistence of infection. In newly diagnosed infants with CF, those without infection had BAL profiles comparable w ith control subjects while those with a lower respiratory infection ha d evidence of airway inflammation. In older children, the development and persistence of infection was accompanied by increased inflammatory markers, whereas these were decreased in the absence, or with the cle arance, of infection. We conclude that airway inflammation follows res piratory infection and, in young children, improves when pathogens are eradicated from the airways.