Fractional analysis of bronchoalveolar lavage fluid cytology in cystic fibrosis patients with normal lung function

Cystic fibrosis (CF) is associated with a neutrophil dominated airway infla mmation. So far bronchoalveolar lavage (BAL) studies in CF have used pooled BAL samples which may be more representative of the alveolar compartment r ather than the airways. To assess whether the first sample of a BAL is more sensitive in the evalua tion of airway inflammation, the authors have studied 105 stable CP patient s aged 5-37 yrs,vith a mean forced expiratory volume in one second (FEV1) o f 96+/-15% (mean+/-SD). BAL cytology of the first and pooled samples were c ompared to reference values obtained in children without respiratory diseas e. Absolute cell counts and the percentage of neutrophils were significantly i ncreased in CF patients, If the 95% confidence interval was used as a cut-o ff point, 17/105 CF patients had a normal percentage of neutrophils in pool ed BAL samples, but only three also had a normal percentage of neutrophils in the first BAL aliquot. Therefore, neutrophil dominated airway inflammation is more pronounced in t he first, mainly bronchial, bronchoalveolar lavage sample suggesting that s equential analysis of bronchoalveolar lavage fluid may have a higher sensit ivity to detect early inflammatory changes in CF patients.